Colloidal Nanocrystals as a Platform for Rapid Screening of Charge Trap Passivating Molecules for Metal Halide Perovskite Thin Films

Article abstract of DOI:10.1021/acs.chemmater.8b00414

Charge recombination at surface trap sites is a significant impediment to metal halide perovskite (MHP) thin film-based optoelectronic devices. To passivate the surface charge traps, chemical treatments with molecules that bind to the MHP thin film surfaces can be employed. However, the current approaches to test the trap passivation efficacy of molecules on thin film surface suffer from limited through-put and low statistical significance. Here, we demonstrate the use of colloidal MHP nanocrystals (NCs) as an experimental platform for high-throughput screening of charge trap passivating molecules for MHP thin films. Using CsPbX₃ (X = Br, I) NCs, over 20 molecules were rapidly screened for their surface trap passivation efficacy. Our approach identified trin-butylphosphine (TBPh) as a superb charge trap passivating molecule on MHP surfaces. TBPh treatment brings the photoluminescence quantum yield of CsPbBr₃ NCs to near unity and also results in superior surface trap passivation of MHP thin films, even when compared to a previously reported treatment with pyridine. Our work highlights the benefits of utilizing the high surface area-to-volume ratio of NCs for the accelerated study of surface trap passivation using molecular treatment and then translating the findings to bulk semiconductors. This approach is broadly applicable to a wide range of semiconductors as long as they can be synthesized into NCs.

Full text of DOI:10.1021/acs.chemmater.8b00414

Subscriber access provided by CAL STATE UNIV SAN FRANCISCO
Article
Colloidal Nanocrystals as a Platform for Rapid Screening of Charge
Trap Passivating Molecules for Metal Halide Perovskite Thin Films
Matthew R. Alpert, J. Scott Niezgoda, Alexander Z. Chen, Benjamin
J Foley, Shelby Cuthriell, Lucy U. Yoon, and Joshua J. Choi
Chem. Mater., Just Accepted Manuscript • DOI: 10.1021/acs.chemmater.8b00414 • Publication Date (Web): 18 Jun 2018
Downloaded from http://pubs.acs.org on June 18, 2018
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 13
Chemistry of Materials
1
2
3
4
5
6
7
8
9
10
Matthew R. Alpert, J. Scott Niezgoda, Alexander Z. Chen, Benjamin J. Foley, Shelby Cuthriell, Lucy
U. Yoon and Joshua J. Choi*
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia, 22904, USA.
*Email: jjc6z@virginia.edu
ABSTRACT: Charge recombination at surface trap sites is a significant impediment to metal halide perovskite (MHP) thin
film-based optoelectronic devices. To passivate the surface charge traps, chemical treatments with molecules that bind to the
MHP thin film surfaces can be employed. However, the current approaches to test the trap passivation efficacy of molecules
on thin film surface suffer from limited through-put and low statistical significance. Here, we demonstrate the use of colloidal
MHP nanocrystals (NCs) as an experimental platform for high-throughput screening of charge trap passivating molecules for
MHP thin films. Using CsPbX3 (X = Br, I) NCs, over 20 molecules were rapidly screened for their surface trap passivation
efficacy. Our approach identified tri-n-butylphosphine (TBPh) as a superb charge trap passivating molecule on MHP surfaces.
TBPh treatment brings the photoluminescence quantum yield of CsPbBr3 NCs to near unity and also results in superior surface
trap passivation of MHP thin films, even when compared to a previously reported treatment with pyridine. Our work high-
lights the benefits of utilizing the high surface area-to-volume ratio of NCs for the accelerated study of surface trap passivation
using molecular treatment and then translating the findings to bulk semiconductors. This approach is broadly applicable to a
wide range of semiconductors as long as they can be synthesized into NCs.
Over the past decade, metal halide perovskites
(MHPs) have generated a tremendous amount of interest
due to their high performance in a wide array of optoelec-
tronic devices such as solar cells,1-8 light-emitting diodes
(LEDS),9-13 photodetectors,14-17 lasing,18-20 and sensors.21 In
particular, MHP solar cells have achieved power conversion
efficiencies (PCE) approaching 23%,22 which is on-par with
the silicon solar cells and the highest among all low-cost so-
lution processable materials. The high device performance
of MHPs stems from a combination of their favorable prop-
erties such as a high light absorption coefficient, long charge
carrier diffusion lengths,23-26 and long carrier lifetimes.27-32
trap passivation on MHP thin films while other molecules
containing amine/ammonium,44, 49, 52, 62-66 phosphonic ac-
ids,53, 67 and sulfur-containing head groups including thiols,
thiophene, and/or thiocyanate32, 41, 47, 50, 54, 68 have been em-
ployed as well. However, most of the previous reports have
been limited in the number of molecules per study. Chal-
lenges associated with overcoming low signals from surface
states versus bulk states, while also employing a large
enough sample size to build statistical significance, have
limited the number of molecules that can be used in system-
atic and controlled comparison experiments with thin films.
These obstacles have impeded the identification of optimal
trap passivating molecules and rendered a more complete
understanding of the relationship between surface chemis-
try and charge trap sites elusive.
However, despite the progress so far, there are still
major challenges to be overcome for MHP devices.13, 17, 33-35
A particularly important issue is understanding and con-
trolling the charge recombination in MHPs. Recently, Yang
et al.28 demonstrated that charge recombination on the top
and bottom surfaces of the polycrystalline thin films typi-
cally employed in devices is orders of magnitude higher
than the bulk recombination. Additionally, there have been
numerous studies examining the impact of the external en-
vironment (e.g. inert atmosphere, ambient conditions, high
oxygen conditions, under vacuum, etc.)7, 36-40 on charge re-
combination at the surface of these materials. These studies
highlight the importance of controlling charge trapping at
surface defects in order to achieve improved device perfor-
mance.28, 35, 41-44
Here we demonstrate colloidal nanocrystals (NCs)
as an experimental platform for high-throughput screening
of surface trap passivation molecules for semiconductor
thin films. Utilizing NCs as a model system for thin films
surfaces can help overcome the previously stated chal-
lenges in thin films studies. One advantage is that optical
properties of NCs are strongly influenced by surface states,
alleviating the surface versus bulk signal issues. For exam-
ple, a NC with a 5-nm diameter can have nearly half of its
To passivate the surface charge trap sites, various
approaches have been investigated such as treatment with
organic molecules,29, 41, 44-53 polymers,54-56 and inorganic ma-
57-59
terials such as Al2O3.
Pyridine30, 32, 60, 61 has been the
most commonly employed organic molecule for surface
ACS Paragon Plus Environment

Chemistry of Materials
atoms on the surface, amplifying the surface charge recom-
Page 2 of 13
1
bination effects versus the bulk. Moreover, colloidal NC so-
lutions are compatible with solution-based optical and
chemical characterization methods that produce data with
high signal-to-noise ratios.69, 70 Additionally, a single syn-
thesis batch of NCs can produce gram-scale quantities with
only a few milligrams required per test with colloidal solu-
tion. This allows for a single batch of NCs to provide dozens
of individual surface passivation tests on identical samples,
facilitating consistency in comparative studies with a large
variety of test molecules.71 In this study, we exploited these
attributes to perform a systematic and comparative study of
various candidate molecules for surface trap passivation on
MHP NCs and tested the validity of translating the NC
screening results to thin film samples. As a model system,
we employed CsPbX3 (X = Br, I) NCs to rapidly screen 23
molecules with various head groups. Our approach identi-
fied tri-n-butylphosphine (TBPh) as a trap passivating mol-
ecule that exhibited higher efficacy when compared to pre-
viously reported molecules, such as pyridine. TBPh was
found to increase the photoluminescence quantum yield
(PLQY) of NCs to near unity. Applying a TBPh treatment to
various MHP thin film compositions resulted in superior PL
intensity and lifetime improvements compared to un-
treated control and equimolar pyridine-treated films. Fi-
nally, the TBPh treatment was applied to MHP solar cell de-
vices and resulted in increased open-circuit voltage (VOC),
fill factor (FF), and PCE.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
CsPbBr3 and CsPbI3 NCs were synthesized via the
hot-injection method developed by Protesecu et al.72 (see
Methods section for details). The two halide compositions
were examined in order to probe any possible halide-de-
pendent responses to the surface treatments.73-76 The as-
synthesized NCs were characterized with absorbance spec-
troscopy, PL spectroscopy, and high-resolution transmis-
sion electron microscopy (HR-TEM) (Figure 1). For the pur-
poses of this work, the NCs with edge lengths averaging 10
nm were prepared such that they have minimal quantum
confinement effects and therefore an electronic structure
closer to their bulk crystal counterparts.72 As seen in Figure
1A and B, both CsPbBr3 and CsPbI3 NCs are cubic shaped
with relatively narrow size dispersions of 8% and 10%, re-
spectively.
Figure 1. Characterization of the as-synthesized CsPbX3 NC
using high-resolution transmission electron microscopy
(TEM) for (a) CsPbBr3 and (b) CsPbI3 NCs as well as (c) NC
absorption and photoluminescence spectra.
more common method of adding OLAM and OA during pu-
rification (see purification method 2 in Methods section),
which resulted in initial NC PLQY of 73%, consistent with
the previously reported PLQY values63, 67, 68, 72, 73, 77-81
.
The candidate molecules for surface trap pas-
sivation were added to solutions of the as-synthesized NCs
and the PLQY was subsequently measured. The ligand ex-
change is expected to occur quickly based on the law of
mass action and the dynamic equilibrium between free and
bound ligands on NC surfaces.82 Moreover, De Roo et al.77
revealed that the ligand-surface interactions in MHP NCs
are even more dynamic compared to metal chalcogenide NC
systems such as PbSe or CdSe. In order to better understand
the PLQY results, one must consider a multitude of factors
starting with the notion that the added ligand molecules can
either bind directly to the surface or undergo ligand ex-
change reactions with the natively bound ligands (OLAM
and OA in our model system72, 77). The binding motif of the
ligand molecules can be understood through the covalent
bond classification developed by M. L. H. Green.83, 84 In par-
ticular, the native oleylammonium (OLAM+) and oleate (OA-
) ligands are thought to bind to the surface of the NCs as a
pair of X-type ligands.77 Therefore, other ligand species that
can undergo proton exchange reactions to form charged
head groups, such as carboxylic acids, amines, or thiols, can
be involved in X-type ligand exchange reactions with the
The purification of the NCs was modified to avoid
the use of excess oleylamine (OLAM) and oleic acid (OA) and
provide the barest possible surface of the NCs (see purifica-
tion method 1 in Methods section for details). The relatively
more exposed surfaces increase the sensitivity to the ligand
treatment tests. This point will be further elaborated on
later. PLQY was employed to monitor the non-radiative
charge trapping in the NCs and was measured as a function
of concentration of the various test ligand molecules in so-
lution. The starting PLQYs for the as-synthesized CsPbBr3
and CsPbI3 NCs were 58% and 29% respectively. It should
be noted that these PLQY values are lower than previously
reported values63, 67, 68, 72, 73, 77-79 but should be expected due
to the intentional modification of the purification process in
which excess OLAM and OA were not added. To check for
any dependence of results on initial NC surface quality and
PLQY, we also prepared another set of CsPbBr3 NCs with a
ACS Paragon Plus Environment

Page 3 of 13
Chemistry of Materials
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
Figure 2. Photoluminescence quantum yield (PLQY) results of (a) CsPbBr3 and (b) CsPbI3 NCs, which have a mixture of oleic
acid (OA) and oleylamine (OLAM) as the native ligands, in response to ligand additions. The PLQY of the as-synthesized NCs are
indicated as the dotted lines. The (⋆) is placed next to samples that showed increased PLQY upon initial scans but did not show
NC stability lasting beyond 1 hour in solution. The overall error of the relative PLQY method is ±3%.
native ligands. Further, it is possible that L-type ligands
Z-type ligands, such as lead (II) oleate (Pb(oleate)2), can ex-
change with other native Z-type ligands. Lastly, L-type and
Z-type ligands can bind with each other through a Lewis
54
55
56
57
58
59
60
(Lewis bases such as phosphines, pyridine, thiophene, or
amines) may undergo a ligand exchange reaction with na-
tively bound L-type ligands.77, 82, 83 Electron pair accepting
ACS Paragon Plus Environment

Chemistry of Materials
Page 4 of 13
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 3. PL intensity and lifetime for (a-b) CsPbBrI2 and (c-d) CsPbI3 thin films comparing untreated films to TBPh-
and pyridine-treated films. The CsPbBrI2 films exhibited almost three orders of magnitude increase in PL intensity
with the TBPh treatments as well as an increase in lifetime, indicating increased surface passivation.
acid-base reaction, which can lead to the removal of both
species from the NC surface.82
groups versus trap passivation efficacy. These molecules
are expected to interact with surface Pb or Cs atoms as they
are electron-donating molecules. This study was focused on
studying organic ligand molecules even though there has
been some recent progress in encapsulating perovskite NCs
in inorganic materials.80, 81, 86 Also, it should be noted that
the results can be somewhat convoluted with the potential
removal of the native ligands through various exchange re-
actions with the test molecules. Nonetheless, it should be re-
iterated that we apply the purification modifications to de-
liberately reduce the number of native ligands on the NC
surface and diminish the potential complications with lig-
and exchange mechanisms.
In this work, all three binding motifs outlined
above were utilized to probe their relative efficacy of sur-
face passivation of MHP NCs. Carboxylic acid/amine com-
binations, which form carboxylate and ammonium ions,
were used as X-type ligands77, as they have been previously
demonstrated to act as such together, and chain length was
varied to elucidate potential trends in steric effects. It
would be expected that these X-type pairs would interact
with both the surface bound Pb or Cs atoms while the inter-
action with the Pb atoms is expected to play a more signifi-
cant role in the photoluminescent properties due to the con-
struction of the band edges85 and that shorter chains would
have the potential to allow for greater surface coverage.
Pb(oleate)2 was tested as a Z-type ligand, which is expected
to bind with surface halide sites. Furthermore, several
Lewis base L-type ligands were used in this work — includ-
ing amines, pyridine, thiols, thiophene, sulfoxides, and
phosphines — to investigate the effects of different head
Figure 2 summarizes the results of the various lig-
and additions and can generally be categorized into two
main outcomes – an increase or decrease in NC PLQY with
respect to the additions. A reduction in PLQY can occur if
the added test molecules go through ligand exchange reac-
tions with the native ligand molecules and (1) are less effec-
tive in surface trap passivation compared to the native
ACS Paragon Plus Environment

Page 5 of 13
Chemistry of Materials
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 4. PL intensity and lifetime scans for (a-b) CsPbBrI2 and (c-d) CsPbI3 thin films comparing the control films
to the sulfolane-treated surfaces. Both film compositions exhibit reduced PL intensity and lifetime upon treat-
ment with sulfolane. The lifetimes for the CsPbI3 scans were taken at the respective PL peak positions.
ligands, (2) are unable to stay strongly bound to the NC sur-
provide good surface passivation. Therefore, the rapid,
high-throughput and statistically significant screening of
molecules with NCs can easily identify promising test mole-
cules for thin film samples and devices.
face, and/or (3) too strongly ligate NC components to the
point of NC digestion. The latter is the likely outcome from
the addition of most of the sulfoxides, after which the NC so-
lution turned colorless. This is consistent with previous re-
ports that showed sulfoxides having strong interactions
with Pb2+ ions and typically being used to help solubilize
precursors.1, 4, 87, 88
Among the test molecules that resulted in in-
creased PLQY compared to the as-synthesized NCs, several
factors were considered when selecting the most promising
molecule for the thin films surface trap passivation. First,
the molecules that resulted in poor NC stability (marked by
star symbols in Figure 2) or lowered PLQY at higher concen-
trations were excluded. The reduction in PLQY at higher
concentrations occurs with most of the amine species, the
carboxylic acid/amine combinations, and sulfoxides. Some
of these results are due to dissolution of NCs at high enough
concentration of ligands that bind too strongly to either per-
ovskite components, the likely case with the sulfoxides,1, 4, 87,
88 and in agreement with previous reports of excess OA and
OLAM in the NC solutions causing the dissolution of the
NCs.72, 73, 77 These molecules that digest NCs are not ideal for
subsequent use on thin films in this study as they will likely
result in significant dissolution and/or morphological
changes in thin films. Dissolution of the thin films is
In contrast, addition of molecules such as TBPh
and OA resulted in increased PLQY of both CsPbBr3 and
CsPbI3 NCs, indicating improved trap passivation to the as-
synthesized NC surface. It should be noted that a positive
correlation between PLQY and the ligand addition conclu-
sively identifies the test molecules as effective trap pas-
sivation species for the following reason. A positive correla-
tion necessarily means that either the test molecules bind
to available open surface sites without significantly remov-
ing the native ligands, thus providing additional trap pas-
sivation, or they replace the native ligands and provide
more effective charge trap passivation than the native lig-
ands. In either case, with the observation of increase in
PLQY, one can unambiguously identify molecules that
ACS Paragon Plus Environment

Chemistry of Materials
Page 6 of 13
undoubtedly not desired for their characterization and de-
NCs either on its own or in combination with native OLAM+
and OA- ligands. It is most likely that TBPh is acting as an L-
type ligand and donating a lone pair to a metal ion. While
this is only one possible mechanism whereby TBPh could be
binding to the surface, it is not yet known if it is in a ligand
exchange reaction or a cooperative binding motif. The elu-
cidation of the complex nature of the TBPh binding there-
fore requires detailed spectroscopic investigations. This is
beyond the scope of this work and is being pursued in our
laboratory. Additionally, the TBPh treatment did not alter
the structural integrity of the NCs in the concentration
range used in this study to achieve the high PLQY result, as
can be seen in TEM images in Figure S2. For CsPbI3, the ad-
dition of TBPh resulted in one of the larger increases in
PLQY but only up to 40%. This suggests that, in contrast to
CsPbBr3 case, a combination of TBPh, OLAM+ and OA- lig-
ands are not able to passivate all of surface trap sites on
CsPbI3 NCs, or provide proper changes in the electronic
structure for complete trap removal. Despite the varying
degree with CsPbBr3 and CsPbI3, the increased PLQY for
both upon TBPh addition suggests that TBPh is a promising
candidate molecule for thin films studies.
1
2
3
4
5
6
7
8
vice fabrication, and significant morphological changes will
make it difficult to distinguish whether any response to the
exposure to the test molecules is due to trap passivation by
the molecules or structural changes of the grains. Second,
some molecules such as Pb(oleate)2 showed a peak at cer-
tain ligand concentrations (initial increase at low concen-
trations but reduction at higher concentrations) without
dissolution of NCs, which may be function of ligand-ex-
change reaction equilibria between the new ligands and na-
tive ligands at the NC surface. At lower concentrations, it
may be possible for the new ligands to bind to NC surface
without significantly removing the native ligands, thus re-
sulting in improved PLQY. At higher concentrations, the
new ligands may bind to a large fraction of the native lig-
ands, resulting in their removal from the NC surface. If the
new ligands do not provide as sufficient of trap passivation
as the native ligands, it will result in lowered PLQY. For the
purpose of this study, with the focus being the first demon-
stration of achieving improved surface passivation in thin
films with newly identified ligand molecules from the rapid
NC screening, these molecules were not pursued. Third,
some molecules exhibited significant differences in surface
passivation of CsPbBr3 and CsPbI3 NCs. For example, thio-
phene, pyridine, and dodecanethiol (DDT) appear to im-
prove the PLQY of the CsPbI3 NCs, which is agreement with
previous thin film reports,30, 32, 41, 50 but the same molecules
decrease the PLQY of the CsPbBr3 NCs. These results reveal
that the different halides result in significant differences in
surface chemistry and the nature of traps. This is not sur-
prising since the different halides would cause significant
differences in electronic structure of the band and surface
trap sites. Indeed, previous reports that showed the varying
degrees of complexation strength89 and overall stability
based on halide composition.90-92 The elucidation of the ex-
act binding motif and surface-ligand exchange mechanisms
with different molecules and NC compositions will be highly
valuable. However, that is beyond the scope of this study,
which is focused on the first demonstration of NCs as a
probe for rapid identification of molecules for surface trap
passivation in thin films. Therefore, in this study, we focus
on identifying the most promising molecule for a test study
to see if the NC results get successfully translated to thin
films. Further studies with a larger scope on the NC surface
chemistry are currently being pursued in our laboratory.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
After the NC testing identified TBPh as among the
most promising trap passivation molecules, three composi-
tions (CsPbBr3, CsPbI3, and CsPbBrI2) of MHP thin films
were treated with TBPh to test its trap passivation efficacy
on polycrystalline thin films. The CsPbBr3 and CsPbI3 com-
positions were chosen so as to mirror the NC testing. The
mixed halide CsPbBrI2 was selected due to its increased
phase stability over pure CsPbI3 and capability to form pin-
hole free thin films for device fabrication with promising so-
lar cell performance.93-96 The CsPbBr3 thin films were not
able to be made sufficiently pin-hole free for use in solar cell
devices (Figure S3). For a direct comparison of the charge
trap passivation efficacy of TBPh with previously reported
molecules, it was compared to an equimolar pyridine treat-
ment, which has been the most commonly used molecule in
the literature.30, 32, 60, 61 To treat the films, the TBPh or pyri-
dine ligands were suspended in toluene, a non-polar solvent
that would not induce significant reconstruction of MHP
surface, and statically dispensed on the MHP films before
being spun off (see Methods section for details). SEM images
(Figure S4) show that samples that were treated with TBPh
or pyridine solution in toluene with up to 0.26 mM concen-
trations do not result in any appreciable morphological
changes in MHP thin films.
Ultimately, our screening approach identified
tributylphosphine (TBPh) to be a promising surface trap
passivation molecule for translation to thin films. The addi-
tion of TBPh resulted in improved PLQY for both CsPbBr3
and CsPbI3 compositions while also exhibiting a positive
correlation between concentration and PLQY with reten-
tion of NC stability. In particular, for CsPbBr3, the PLQY rose
to 100%, within an error bar of 3%, upon addition of TBPh.
This improved trap passivation was verified to be inde-
pendent of NC purification method as the similar results
were obtained from NCs prepared with a more common pu-
rification method (see purification method 2 in Methods
section). TBPh treatment increased the PLQY of these NCs
from 73% to 100%, within the uncertainty of the measure-
ment, as well (Figure S1). These results suggest that TBPh
provides a complete surface trap passivation for CsPbBr3
Upon treatment with TBPh, the MHP thin films ex-
hibited significant increases in PL intensity (Figures 3A and
C and Figure S5A for CsPbBr3), up to three orders of magni-
tude for the CsPbBrI2 composition. The TBPh treatments re-
sulted in larger increase in PL intensity as compared to the
equimolar treatment with pyridine which mirrors the re-
sults from NC screening that identified TBPh to be superior
to pyridine in reducing non-radiative recombination at the
surface. In addition to testing molecules that increased
PLQY of NCs, sulfolane treatment was investigated to exam-
ine how species that decreased NC PLQY affect the thin
films. As shown in Figure 4 and Figure S5B, the sulfolane
treatments decreased the PL intensity of all CsPbBrI2,
CsPbI3 and CsPbBr3 thin films. For CsPbI3 film, the sulfolane
ACS Paragon Plus Environment

Page 7 of 13
Chemistry of Materials
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 5. Results from CsPbBrI2 thin film solar cell devices. (a) J-V curves of an untreated and a 0.26 mM TBPh-treated
device, as well as statistics demonstrating the improvement in (b) device PCE, (c) Voc, and (d) FF over the untreated
devices.
treatment led to a red-shift in the PL peak position, indicat-
platform for rapid screening of surface passivating mole-
cules for thin films.
ing that there could be grain/surface reconstruction. None-
theless, these results show that the influence of the chemi-
cal treatment on MHP thin films mirror the NC PLQY results
also for molecules that result in decreased surface trap pas-
sivation.
In order to study the impact of various ligand treat-
ments on solar cell performance, CsPbBrI2 based devices
(ITO/TiO2/CsPbBrI2/Spiro-MeOTAD/Au) were fabricated
and tested. All perovskite thin film deposition, ligand treat-
ment, and subsequent device fabrication and testing steps
were performed inside N2 filled gloveboxes (see Experi-
mental Section for details) to avoid any complications from
exposure to ambient air that may affect surface pas-
sivation.36-38 To this end, Co(III)-doped Spiro-MeOTAD was
used as the hole transporting layer in order to avoid the ox-
idation step in the ambient air required by the more typi-
cally used lithium-doped Spiro-MeOTAD.61, 99-101 Figure 5
shows the results of the device testing for the TBPh-treated
surface with statistics from 36 devices per condition. The
TBPh treatment enhances the overall PCE of the devices,
and in particular the VOC and FF parameters show the larg-
est response. VOC improvements have been linked to a re-
duction in surface recombination through various mecha-
nisms involving shallow and deep trap site alleviation30, 98,
The PL lifetime measurements also show con-
sistent results. TBPh treated CsPbBrI2 and CsPbI3 samples
exhibit slower carrier recombination compared to their re-
spective control as well as pyridine-treated films (Figure
3B, D and Figure S6), while the sulfolane treated films (Fig-
ure 4B and D) exhibit faster carrier recombination versus
the untreated control films. The average lifetimes (Table S1)
for the CsPbBrI2 films increased from 18 ns up to 75 ns with
the TBPh treatments. Since surface recombination has been
shown to have major effect on carrier lifetime,28, 30-32 these
results provide further evidence of the NC PLQY results be-
ing translated to the thin film systems well. These mirroring
results of the NC and thin film samples demonstrate that,
while there may be some differences in how charge carriers
behave in the two systems,97, 98 the NC system is an adequate
102-104
and reducing ion migration at the surfaces.43, 105, 106
ACS Paragon Plus Environment

Chemistry of Materials
Page 8 of 13
model systems and identified tri-n-butylphosphine (TBPh)
1
2
3
4
5
6
7
8
to be a highly effective surface trap passivation molecule for
CsPbX3 MHP thin films and solar cell devices. The approach
demonstrated in this work may be broadly applied to a wide
range of semiconductor materials as long as they can be
synthesized into NCs, but further studies are required to
verify the generality. Having the capability to systematically
study a large array of molecules with the identical samples
and experimental controls will reveal important trends that
would have been difficult to reliably obtain with bulk or thin
film studies. This can lead to accelerated progress towards
a deeper understanding of charge trap sites on semiconduc-
tor surfaces.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Methods
Materials:
All materials were purchased from Sigma Aldrich unless
otherwise specified.
Figure 6. The relationship between PLQY of the CsPbBr3
NCs with the 9.0mM ligand treatments versus the Voc of the
thin film devices treated with the same ligands (sulfolane,
pyridine, “as-synthesized”/controls, and TBPh from left to
right).
Preparation of Cesium Oleate Solution
A stock solution of cesium oleate in octadecene (ODE) was
prepared a procedure similar to Protesescu et al..72 Cs2CO3
(0.407 g) was loaded into a 50mL 3-neck flask along with
20mL ODE and 1.25 mL of oleic acid (HOA). The solution
was dried under vacuum for 1 hour at 120°C and then
heated under argon at 150°C for 30 minutes. Solution was
stored in an N2 glovebox for long-term storage. Solution
was heated to 100°C prior to use in CsPbX3 NC synthesis.
These types of mechanisms can lead to a charge carrier ac-
cumulation at the surface/interface which leads to in-
creased charge recombination and/or the development of
an additional electric field that can hinder charge extrac-
tion.43 While the direct interaction mechanism of the TBPh
is not yet known, it is expected to act as a Lewis base L-type
ligand, meaning its interactions with surface-bound Pb at-
oms would be the most likely mechanism of surface pas-
sivation.32, 82, 83, 107 Under-coordinated Pb atoms can result
in electron trap sites108 which can cause electron accumula-
tion at the perovskite/HTL interface, but the TBPh pas-
sivation would reduce the electron trap sites leading to the
improved VOC and charge extraction.29, 42, 44, 48, 61, 102
CsPbX3 NC Synthesis
CsPbX3 NCs were prepared following previously reported
procedures.72 PbX2 (0.75 mmol), such as (0.276 g PbBr2
[Alfa Aesar 99.999%] or 0.347g PbI2 [TCI 99.999%]), were
loaded into a 100 mL 3-neck flask along with 20 mL ODE, 2
mL OA, and 2 mL oleylamine (OLAM) and then dried under
vacuum at 110°C for 1 hour. The solution was then placed
under an Argon and then heated to the injection tempera-
ture (180°C for CsPbBr3 and 150°C for CsPbI3) before 0.8
mL of warmed cesium oleate were swiftly injected. The so-
lution was placed into an ice bath 5-10 seconds after the in-
jection. After the reaction solution was cooled it was placed
in an Argon atmosphere storage flask via cannula transfer
and brought into the N2 atmosphere glovebox for purifica-
tion.
Similar to the NC testing and thin film results, the
TBPh treatments resulted in superior device performance
compared to equimolar pyridine treatment (Figure S7).
Treatment with sulfolane resulted in reduced Voc and PCE of
solar cells (Figure S7), which is also consistent with the NC
screening results. Figure 6 shows a relationship between
the NC PLQY and the Voc of the thin film devices when
treated with different ligand molecules. It should be noted
that making any direct correlation across different ligand
molecule treatments is complicated by the differences in
surface-ligand and ligand-ligand interactions as well as dif-
ferences depending on perovskite compositions (see Figure
S8 for CsPbI3 NC PLQY results). However, the positive rela-
tionship between the NC PLQY and the Voc of the thin film
devices observed for both CsPbBr3 NCs (Figure 6) and
CsPbI3 NCs (Figure S8) supports the notion that employing
NCs for rapid identification of molecules that can success-
fully passivate thin film surfaces is a good starting point.
CsPbX3 NC Purification
Method 1: The pure reaction solution was centrifuged at
6000 rpm for 40 minutes. The lightly colored supernant
was discarded and the solids were dispersed in 5 mL of tol-
uene [anhydrous]. The new solution was centrifuged at
3000 rpm for 3 minutes to remove large aggregates and the
supernant was saved. The purified solution was stored in
the N2 glovebox for long-term storage.
In conclusion, our report demonstrates colloidal
NCs as high-throughput screening platforms for rapid iden-
tification of surface charge trap passivating molecules for
semiconductor thin films. By utilizing this approach, we
screened more than 20 molecules using CsPbX3 NCs as
Method 2: A method similar to ref. 77 was used, but methyl
acetate (MeOAc) was used in place of acetone77. A 1:1
ACS Paragon Plus Environment

Page 9 of 13
Chemistry of Materials
volume ratio of MeOAc to reaction solution was centrifuged
at 6000 rpm for 20 minutes. The supernant was discarded
CsPbBrI2 Solar Cell Devices
1
2
3
4
5
6
7
8
and the solids were dispersed in 5 mL of toluene [anhy-
drous]. 4 vol.% dried HOA and 4 vol% dried OLAM were
added to the solution and agitated. 5 mL of MeOAc was then
added to the solution and was centrifuged at 6000 rpm for
20 minutes. The supernant was discarded and the solids
were again dispersed in 5 mL of toluene. 1.5 vol.% dried
HOA and 1.5 vol.% dried OLAM were then added to the so-
lution. 5 mL of MeOAc was added to the solution and was
again centrifuged at 6000 rpm for 20 minutes. The super-
nant was again discarded and 5 mL of toluene was added to
the remaining solids. The solution was centrifuged at 3000
rpm for 3 minutes to removes excessively large solids and
supernant was saved. The purified solution was stored in
the N2 glovebox for long-term storage.
Pre-patterned ITO substrates were cleaned via sonication
using a Hellmanex soap solution for 5 minutes, followed by
sonication in DI H2O and then ethanol. The clean substrates
were then UV-ozone treated for 5 minutes. Compact tita-
nium dioxide (c-TiO2) electrodes were prepared by spin
casting a solution of 146 µL Ti(iPO)2(acac)2 in 2 mL butanol
[anhydrous] at 4,000 rpm for 60 seconds. The films were
then annealed at 500°C for 5 minutes and transferred to the
nitrogen glovebox after cooling. The perovskite films were
cast in the same method described above. Once the films
had cooled, the top film surface was treated. For the control
samples, 300 µL of toluene was placed on the film and al-
lowed to sit for 60 seconds before spinning off at 3,000 rpm.
For the treated films, the 300 µL of toluene was replaced by
a solution containing the specified ligand concentration in
toluene and allowed to sit for 60 seconds before spinning
off at 3,000 rpm as well. Subsequently, 45 µL of Spiro-
MeTAD solution (72 mg Spiro-MeTAD [Lumtec], 17.5 µL of
1.8M Li:TFSI in acetonitrile [anhydrous], 29.0 µL of 0.2M
FK209 [Lumtec] in acetonitrile, and 28.8 µL of tBP in 1.0 mL
of chlorobenzene [anhydrous]) was dynamically dispensed
at 4,000 rpm for 30 seconds and then dried at 60°C for 10
minutes. The devices were then finished with 50 nm Ag
electrodes. The fabricated solar cells were then tested un-
der N2 atmosphere to keep them completely isolated from
oxygen and moisture.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Ligand Additions
Materials used for ligand species were either anhydrous or
dried using a “freeze, pump, thaw” method and brought into
the N2 glovebox. Species used were: acetic acid (AceticA),
octanoic acid (OctA), oleic acid (OA), propylamine (Pro-
pAM), butylamine (ButAM), tributylamine (TriButAM), oc-
tylamine (OctAM), olyelamine (OLAM), sulfolane, dimethyl
sulfoxide (DMSO), butyl sulfoxide (BSO), phenyl vinyl sul-
foxide (PVSO), 1-tetrahydrothiophene oxide (THTO), tetra-
hydrothiophene (THT), thiophene, pyridine, tri-n-butyl
phosphine (TBPh), dodecane thiol (DDT), and
trioctylphosphine (TOPh).
Optical Characterization
Lead oleate (Pb(oleate)2) was synthesized by adding 1M
PbO and 2M HOA to ODE. The solution was then heated to
120°C under vacuum for 1 hour. The solution was placed
under Argon and transferred to a storage flask also under
Argon for transfer and storage in the N2 glovebox. The so-
lution was warmed to 50°C prior to usage since it was a
solid at room temperature.
Photoluminescence (PL) spectra were collected on a PTI
Quantamaster 400 (QM-400) system. For thin film samples,
the perovskite films were kept from air exposure using a
glass slide and UV-cured epoxy to seal the edges. Absorb-
ance spectra were collected using a PerkinElmer Lambda
950S spectrophotometer. For photoluminescence quantum
yield (PLQY) measurements were collected using the rela-
tive PLQY method, which was first verified using Rhoda-
mine 6G and Rhodamine 101, and then appropriate stand-
ard fluorescent dyes were used for NP measurements. Flu-
orescent lifetimes were measured using time correlated sin-
gle photon counting (TCSPC) setup on the QM-400 system
using a 633 nm laser diode. Average lifetimes were ob-
tained by fitting decay curves with a biexponential function
and then using the integrated area under the curve repre-
senting each function to calculate a weighted average.
CsPbX3 Thin Films
CsPbX3 films were produced following previous reports.94-96
0.43 M solutions consisting of 0.224 g CsI [Alfa Aesar
99.999%] and appropriate ratios of PbBr2 and PbI2, based
on desired final halide composition, were placed in 2 mL di-
methylformamide (DMF) [anhydrous] and stirred at 60°C
for 1 hour to fully dissolve components. The solution was
then passed through a 0.2 µm PTFE syringe filter and into a
storage vial. Care was taken to make sure solution did not
crystallize on the threads or sides of the vial. Thin films
were prepared by dynamically dispensing 45 µL of the fil-
tered precursor solution at 1,500 rpm for 50 seconds. The
resulting film was then annealed for 10 minutes at either
345°C for the CsPbBrI2 films and 350°C for the CsPbI3 films.
Electron Microscopy
High-resolution transmission electron microscopy (TEM)
images were taken using a FEI Titan 80-300 TEM using 300
kV accelerating voltage. All images were taken at room tem-
perature and care was taken to prepare TEM grinds in such
a way that minimized air exposure. Scanning electron mi-
croscopy (SEM) images were taken on a Quanta 650 SEM
operating at 5 kV. All samples were imaged in multiple lo-
cations to confirm homogeneity of samples and images
shown are representative of center areas of prepared films.
The CsPbBr3 solutions replaced the DMF with dimethyl sul-
foxide (DMSO) [anhydrous]. Additionally, the solution was
dynamically dispensed at 1,500 rpm for 60 seconds and 200
µL of chlorobenzene was dropped on the film 45 seconds
into spinning in order to increase surface coverage. The re-
sulting films were then annealed at 330°C for 10 minutes.
Solar Cell Testing
ACS Paragon Plus Environment

Chemistry of Materials
Page 10 of 13
Griffiths, J. T.; Ducati, C.; Menke, S. M.; Deschler, F.; Greenham, N. C.,
The devices were tested using a Keithley source-meter us-
ing a scan rate of 1 V/s under AM 1.5 illumination from a
solar simulator (PV Measurements). The light source was
calibrated using a reference silicon solar cell (PV Measure-
ments). The device area was 0.03 cm2. An optical mask was
used to block illumination to the non-device area during
testing.
Photon Reabsorption in Mixed CsPbCl3:CsPbI3 Perovskite
Nanocrystal Films for Light-Emitting Diodes. J. Phys. Chem C 2017,
121, 3790-3796.
1
2
3
4
5
6
10.
Kim, Y.-H.; Wolf, C.; Kim, Y.-T.; Cho, H.; Kwon, W.; Do, S.;
Sadhanala, A.; Park, C. G.; Rhee, S.-W.; Im, S. H.; Friend, R. H.; Lee, T.-
W., Highly Efficient Light-Emitting Diodes of Colloidal Metal–
Halide Perovskite Nanocrystals beyond Quantum Size. ACS Nano
2017, 11, 6586-6593.
7
8
9
11.
Song, J.; Li, J.; Li, X.; Xu, L.; Dong, Y.; Zeng, H., Quantum Dot
Light-Emitting Diodes Based on Inorganic Perovskite Cesium Lead
Halides (CsPbX3). Adv. Mater. 2015, 27, 7162-7167.
Supporting Information available: Additional PL and lifetime
data, SEM images, and device statistics are provided. This in-
formation is available free of charge at http://pubs.acs.org.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
12.
Zhou, J. C.; Hu, Z. B.; Zhang, L. Z.; Zhu, Y., Perovskite
CsPbBr1.2I1.8 quantum dot alloying for application in white light-
emitting diodes with excellent color rendering index. J. Alloys
Compd. 2017, 708, 517-523.
13.
Stranks, S. D.; Snaith, H. J., Metal-halide perovskites for
photovoltaic and light-emitting devices. Nat. Nanotechnol. 2015,
10, 391-402.
*Email: jjc6z@virginia.edu
14.
Dou, L.; Yang, Y.; You, J.; Hong, Z.; Chang, W.-H.; Li, G.;
Yang, Y., Solution-processed hybrid perovskite photodetectors
with high detectivity. Nat. Commun. 2014, 5, 5404, 1-4.
J. S. N.: Department of Chemistry, Saint Joseph's University,
Philadelphia, Pennsylvania 19131
15.
materials and devices. Chem. Soc. Rev. 2017, 46, 5204-5236.
16. Zhang, J. R.; Wang, Q.; Zhang, X. S.; Jiang, J. X.; Gao, Z. F.;
Jin, Z. W.; Liu, S. Z., High-performance transparent ultraviolet
photodetectors based on inorganic perovskite CsPbCl3
nanocrystals. RSC Adv. 2017, 7, 36722-36727.
Wang, H.; Kim, D. H., Perovskite-based photodetectors:
Joshua J. Choi: 0000-0002-90136926
17.
García de Arquer, F. P.; Armin, A.; Meredith, P.; Sargent,
The authors declare no competing financial interest.
E. H., Solution-processed semiconductors for next-generation
photodetectors. Nature Reviews Materials 2017, 2, 16100, 1-49.
18.
Fu, Y. P.; Zhu, H. M.; Stoumpos, C. C.; Ding, Q.; Wang, J.;
This work was supported by a start-up fund from the Univer-
sity of Virginia.
Kanatzidis, M. G.; Zhu, X. Y.; Jin, S., Broad Wavelength Tunable
Robust Lasing from Single-Crystal Nanowires of Cesium Lead
Halide Perovskites (CsPbX3, X = Cl, Br, I). Acs Nano 2016, 10, 7963-
7972.
19.
Yakunin, S.; Protesescu, L.; Krieg, F.; Bodnarchuk, M. I.;
1.
Ahn, N.; Son, D.-Y.; Jang, I.-H.; Kang, S. M.; Choi, M.; Park,
Nedelcu, G.; Humer, M.; De Luca, G.; Fiebig, M.; Heiss, W.;
Kovalenko, M. V., Low-threshold amplified spontaneous emission
and lasing from colloidal nanocrystals of caesium lead halide
perovskites. Nat. Commun. 2015, 6, 8056, 1-8.
N.-G., Highly Reproducible Perovskite Solar Cells with Average
Efficiency of 18.3% and Best Efficiency of 19.7% Fabricated via
Lewis Base Adduct of Lead(II) Iodide. J. Am. Chem. Soc. 2015, 137,
8696-8699.
20.
sources. Nat. Photonics 2016, 10, 295-302.
21. Stoumpos, C. C.; Malliakas, C. D.; Peters, J. A.; Liu, Z.;
Sebastian, M.; Im, J.; Chasapis, T. C.; Wibowo, A. C.; Chung, D. Y.;
Freeman, A. J.; Wessels, B. W.; Kanatzidis, M. G., Crystal Growth of
the Perovskite Semiconductor CsPbBr3: A New Material for High-
Energy Radiation Detection. Cryst. Growth Des. 2013, 13, 2722-
2727.
22.
https://www.nrel.gov/pv/assets/images/efficiency-chart.png
23. Adhyaksa, G. W. P.; Veldhuizen, L. W.; Kuang, Y.;
Brittman, S.; Schropp, R. E. I.; Garnett, E. C., Carrier Diffusion
Lengths in Hybrid Perovskites: Processing, Composition, Aging,
and Surface Passivation Effects. Chem. Mater. 2016, 28, 5259-
5263.
Sutherland, B. R.; Sargent, E. H., Perovskite photonic
2.
Jeon, N. J.; Noh, J. H.; Yang, W. S.; Kim, Y. C.; Ryu, S.; Seo, J.;
Seok, S. I., Compositional engineering of perovskite materials for
high-performance solar cells. Nature 2015, 517, 476-480.
3.
Kim, Y. G.; Kim, T. Y.; Oh, J. H.; Choi, K. S.; Kim, Y. J.; Kim, S.
Y., Cesium lead iodide solar cells controlled by annealing
temperature. Phys. Chem. Chem. Phys. 2017, 19, 6257-6263.
4.
Lee, J.-W.; Kim, H.-S.; Park, N.-G., Lewis Acid–Base Adduct
Approach for High Efficiency Perovskite Solar Cells. Acc. Chem. Res.
2016, 49, 311-319.
Chart,
N.
P.
E.
5.
Li, X.; Bi, D.; Yi, C.; Decoppet, J. D.; Luo, J.; Zakeeruddin, S.
M.; Hagfeldt, A.; Gratzel, M., A vacuum flash-assisted solution
process for high-efficiency large-area perovskite solar cells. Science
2016, 353, 58-62.
6.
Roldán-Carmona, C.; Gratia, P.; Zimmermann, I.; Grancini,
G.; Gao, P.; Graetzel, M.; Nazeeruddin, M. K., High efficiency
methylammonium lead triiodide perovskite solar cells: the
relevance of non-stoichiometric precursors. Energy Environ. Sci.
2015, 8, 3550-3556.
24.
Shi, D.; Adinolfi, V.; Comin, R.; Yuan, M.; Alarousu, E.;
Buin, A.; Chen, Y.; Hoogland, S.; Rothenberger, A.; Katsiev, K.;
Losovyj, Y.; Zhang, X.; Dowben, P. A.; Mohammed, O. F.; Sargent, E.
H.; Bakr, O. M., Low trap-state density and long carrier diffusion in
organolead trihalide perovskite single crystals. Science 2015, 347,
519-522.
7.
Wu, C.-G.; Chiang, C.-H.; Tseng, Z.-L.; Nazeeruddin, M. K.;
Hagfeldt, A.; Grätzel, M., High efficiency stable inverted perovskite
solar cells without current hysteresis. Energy Environ. Sci. 2015, 8,
2725-2733.
25.
Stranks, S. D.; Eperon, G. E.; Grancini, G.; Menelaou, C.;
Alcocer, M. J. P.; Leijtens, T.; Herz, L. M.; Petrozza, A.; Snaith, H. J.,
Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an
Organometal Trihalide Perovskite Absorber. Science 2013, 342,
341-344.
8.
Yang, M.; Zhou, Y.; Zeng, Y.; Jiang, C.-S.; Padture, N. P.; Zhu,
K., Square-Centimeter Solution-Processed Planar CH3NH3PbI3
Perovskite Solar Cells with Efficiency Exceeding 15%. Adv. Mater.
2015, 27, 6363-6370.
26.
Xing, G.; Mathews, N.; Sun, S.; Lim, S. S.; Lam, Y. M.;
9.
Davis, N. J. L. K.; de la Peña, F. J.; Tabachnyk, M.; Richter,
Gratzel, M.; Mhaisalkar, S.; Sum, T. C., Long-Range Balanced
J. M.; Lamboll, R. D.; Booker, E. P.; Wisnivesky Rocca Rivarola, F.;
ACS Paragon Plus Environment

Page 11 of 13
Chemistry of Materials
Electron- and Hole-Transport Lengths in Organic-Inorganic
CH3NH3PbI3. Science 2013, 342, 344-347.
27. Wu, X.; Trinh, M. T.; Niesner, D.; Zhu, H.; Norman, Z.;
Owen, J. S.; Yaffe, O.; Kudisch, B. J.; Zhu, X. Y., Trap States in Lead
Iodide Perovskites. J. Am. Chem. Soc. 2015, 137, 2089-2096.
44.
Zuo, L.; Chen, Q.; De Marco, N.; Hsieh, Y.-T.; Chen, H.; Sun,
P.; Chang, S.-Y.; Zhao, H.; Dong, S.; Yang, Y., Tailoring the Interfacial
Chemical Interaction for High-Efficiency Perovskite Solar Cells.
Nano Lett. 2017, 17, 269-275.
1
2
3
4
5
6
7
8
45.
Heo, J. H.; Han, H. J.; Kim, D.; Ahn, T. K.; Im, S. H.,
28.
Yang, Y.; Yang, M.; Moore, David T.; Yan, Y.; Miller,
Hysteresis-less inverted CH3NH3PbI3 planar perovskite hybrid
solar cells with 18.1% power conversion efficiency. Energy
Environ. Sci. 2015, 8, 1602-1608.
Elisa M.; Zhu, K.; Beard, Matthew C., Top and bottom surfaces limit
carrier lifetime in lead iodide perovskite films. Nat. Energy 2017,
2, 16207, 1-7.
46.
Jacobsson, T. J.; Correa-Baena, J.-P.; Halvani Anaraki, E.;
29.
Chen, Q.; Zhou, H.; Song, T.-B.; Luo, S.; Hong, Z.; Duan, H.-
Philippe, B.; Stranks, S. D.; Bouduban, M. E. F.; Tress, W.; Schenk, K.;
Teuscher, J.; Moser, J.-E.; Rensmo, H.; Hagfeldt, A., Unreacted PbI2
as a Double-Edged Sword for Enhancing the Performance of
Perovskite Solar Cells. J. Am. Chem. Soc. 2016, 138, 10331-10343.
S.; Dou, L.; Liu, Y.; Yang, Y., Controllable Self-Induced Passivation of
Hybrid Lead Iodide Perovskites toward High Performance Solar
Cells. Nano Lett. 2014, 14, 4158-4163.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
30.
de Quilettes, D. W.; Vorpahl, S. M.; Stranks, S. D.; Nagaoka,
47.
Ke, W.; Xiao, C.; Wang, C.; Saparov, B.; Duan, H.-S.; Zhao,
H.; Eperon, G. E.; Ziffer, M. E.; Snaith, H. J.; Ginger, D. S., Impact of
microstructure on local carrier lifetime in perovskite solar cells.
Science 2015, 348, 683-686.
D.; Xiao, Z.; Schulz, P.; Harvey, S. P.; Liao, W.; Meng, W.; Yu, Y.;
Cimaroli, A. J.; Jiang, C.-S.; Zhu, K.; Al-Jassim, M.; Fang, G.; Mitzi, D.
B.; Yan, Y., Employing Lead Thiocyanate Additive to Reduce the
Hysteresis and Boost the Fill Factor of Planar Perovskite Solar
Cells. Adv. Mater. 2016, 28, 5214-5221.
31.
deQuilettes, D. W.; Koch, S.; Burke, S.; Paranji, R. K.;
Shropshire, A. J.; Ziffer, M. E.; Ginger, D. S., Photoluminescence
Lifetimes Exceeding 8 μs and Quantum Yields Exceeding 30% in
Hybrid Perovskite Thin Films by Ligand Passivation. ACS Energy
Lett. 2016, 1, 438-444.
48.
Shao, Y.; Xiao, Z.; Bi, C.; Yuan, Y.; Huang, J., Origin and
elimination of photocurrent hysteresis by fullerene passivation in
CH3NH3PbI3 planar heterojunction solar cells. Nat. Commun. 2014,
5, 5784, 1-7.
32.
Noel, N. K.; Abate, A.; Stranks, S. D.; Parrott, E. S.;
Burlakov, V. M.; Goriely, A.; Snaith, H. J., Enhanced
Photoluminescence and Solar Cell Performance via Lewis Base
Passivation of Organic–Inorganic Lead Halide Perovskites. ACS
Nano 2014, 8, 9815-9821.
49.
Son, D.-Y.; Lee, J.-W.; Choi, Y. J.; Jang, I.-H.; Lee, S.; Yoo, P.
J.; Shin, H.; Ahn, N.; Choi, M.; Kim, D.; Park, N.-G., Self-formed grain
boundary healing layer for highly efficient CH3 NH3 PbI3
perovskite solar cells. Nat. Energy 2016, 1, 16081, 1-8.
33.
Park, N.-G.; Grätzel, M.; Miyasaka, T.; Zhu, K.; Emery, K.,
50.
Stewart, R. J.; Grieco, C.; Larsen, A. V.; Maier, J. J.; Asbury,
Towards stable and commercially available perovskite solar cells.
J. B., Approaching Bulk Carrier Dynamics in Organo-Halide
Perovskite Nanocrystalline Films by Surface Passivation. J. Phys.
Chem Lett. 2016, 7, 1148-1153.
Nat. Energy 2016, 1, 16152, 1-8.
34.
perovskites for energy applications. Nat. Energy 2016, 1, 16048.
35. Ye, M.; He, C.; Iocozzia, J.; Liu, X.; Cui, X.; Meng, X.; Rager,
M.; Hong, X.; Liu, X.; Lin, Z., Recent advances in interfacial
engineering of perovskite solar cells. J. Phys. D: Appl. Phys. 2017,
50, 373002, 1-16.
Zhang, W.; Eperon, G. E.; Snaith, H. J., Metal halide
51.
Sun, C.; Xue, Q.; Hu, Z.; Chen, Z.; Huang, F.; Yip, H.-L.; Cao,
Y., Phosphonium Halides as Both Processing Additives and
Interfacial Modifiers for High Performance Planar-Heterojunction
Perovskite Solar Cells. Small 2015, 11, 3344-3350.
52.
Wang, F.; Geng, W.; Zhou, Y.; Fang, H.-H.; Tong, C.-J.; Loi,
36.
Aristidou, N.; Eames, C.; Sanchez-Molina, I.; Bu, X.; Kosco,
M. A.; Liu, L.-M.; Zhao, N., Phenylalkylamine Passivation of
Organolead Halide Perovskites Enabling High-Efficiency and Air-
Stable Photovoltaic Cells. Adv. Mater. 2016, 28, 9986-9992.
J.; Islam, M. S.; Haque, S. A., Fast oxygen diffusion and iodide defects
mediate oxygen-induced degradation of perovskite solar cells. Nat.
Commun. 2017, 8, 15218, 1-10.
53.
Li, X.; Ibrahim Dar, M.; Yi, C.; Luo, J.; Tschumi, M.;
37.
Fang, H. H.; Adjokatse, S.; Wei, H.; Yang, J.; Blake, G. R.;
Zakeeruddin, S. M.; Nazeeruddin, M. K.; Han, H.; Grätzel, M.,
Improved performance and stability of perovskite solar cells by
crystal crosslinking with alkylphosphonic acid ω-ammonium
chlorides. Nat. Chem. 2015, 7, 703-711.
Huang, J.; Even, J.; Loi, M. A., Ultrahigh sensitivity of
methylammonium lead tribromide perovskite single crystals to
environmental gases. Sci. Adv. 2016, 2, 1600534-1600534.
38.
Galisteo-López, J. F.; Anaya, M.; Calvo, M. E.; Míguez, H.,
54.
Lin, Y.; Shen, L.; Dai, J.; Deng, Y.; Wu, Y.; Bai, Y.; Zheng, X.;
Environmental Effects on the Photophysics of Organic–Inorganic
Halide Perovskites. J. Phys. Chem Lett. 2015, 6, 2200-2205.
Wang, J.; Fang, Y.; Wei, H.; Ma, W.; Zeng, X. C.; Zhan, X.; Huang, J., π-
Conjugated Lewis Base: Efficient Trap-Passivation and Charge-
Extraction for Hybrid Perovskite Solar Cells. Adv. Mater. 2017, 29,
1604545.
39.
Grancini, G.; D'Innocenzo, V.; Dohner, E. R.; Martino, N.;
Srimath Kandada, A. R.; Mosconi, E.; De Angelis, F.; Karunadasa, H.
I.; Hoke, E. T.; Petrozza, A., CH3NH3PbI3 perovskite single crystals:
surface photophysics and their interaction with the environment.
Chem. Sci. 2015, 6, 7305-7310.
55.
Tripathi, N.; Shirai, Y.; Yanagida, M.; Karen, A.; Miyano, K.,
Novel Surface Passivation Technique for Low-Temperature
Solution-Processed Perovskite PV Cells. ACS Appl. Mater. Interfaces
2016, 8, 4644-4650.
40.
Müller, C.; Glaser, T.; Plogmeyer, M.; Sendner, M.; Döring,
S.; Bakulin, A. A.; Brzuska, C.; Scheer, R.; Pshenichnikov, M. S.;
Kowalsky, W.; Pucci, A.; Lovrinčić, R., Water Infiltration in
Methylammonium Lead Iodide Perovskite: Fast and
Inconspicuous. Chem. Mater. 2015, 27, 7835-7841.
56.
Xu, M.; Feng, J.; Ou, X.-L.; Zhang, Z.-Y.; Zhang, Y.-F.; Wang,
H.-Y.; Sun, H.-B., Surface Passivation of Perovskite Film by Small
Molecule Infiltration for Improved Efficiency of Perovskite Solar
Cells. IEEE Photonics J. 2016, 8, 1-7.
41.
Cao, J.; Yin, J.; Yuan, S.; Zhao, Y.; Li, J.; Zheng, N., Thiols as
57.
Guarnera, S.; Abate, A.; Zhang, W.; Foster, J. M.;
interfacial modifiers to enhance the performance and stability of
Richardson, G.; Petrozza, A.; Snaith, H. J., Improving the Long-Term
Stability of Perovskite Solar Cells with a Porous Al2O3 Buffer Layer.
J. Phys. Chem Lett. 2015, 6, 432-437.
perovskite solar cells. Nanoscale 2015, 7, 9443-9447.
42.
Grancini, G.; Viola, D.; Lee, Y.; Saliba, M.; Paek, S.; Cho, K.
T.; Orlandi, S.; Cavazzini, M.; Fungo, F.; Hossain, M. I.; Belaidi, A.;
Tabet, N.; Pozzi, G.; Cerullo, G.; Nazeeruddin, M. K., Femtosecond
Charge-Injection Dynamics at Hybrid Perovskite Interfaces.
ChemPhysChem 2017, 18, 2381-2389.
58.
Kot, M.; Das, C.; Wang, Z.; Henkel, K.; Rouissi, Z.;
Wojciechowski, K.; Snaith, H. J.; Schmeisser, D., Room-Temperature
Atomic Layer Deposition of Al2O3: Impact on Efficiency, Stability
and Surface Properties in Perovskite Solar Cells. ChemSusChem
2016, 9, 3401-3406.
43.
Zarazua, I.; Han, G.; Boix, P. P.; Mhaisalkar, S.; Fabregat-
Santiago, F.; Mora-Seró, I.; Bisquert, J.; Garcia-Belmonte, G., Surface
Recombination and Collection Efficiency in Perovskite Solar Cells
from Impedance Analysis. J. Phys. Chem Lett. 2016, 7, 5105-5113.
59.
Si, H.; Liao, Q.; Zhang, Z.; Li, Y.; Yang, X.; Zhang, G.; Kang,
Z.; Zhang, Y., An innovative design of perovskite solar cells with Al
ACS Paragon Plus Environment

Chemistry of Materials
Page 12 of 13
2 O 3 inserting at ZnO/perovskite interface for improving the
performance and stability. Nano Energy 2016, 22, 223-231.
60. Ahmed, G. H.; Yin, J.; Bose, R.; Sinatra, L.; Alarousu, E.;
Yengel, E.; AlYami, N. M.; Saidaminov, M. I.; Zhang, Y.; Hedhili, M. N.;
Bakr, O. M.; Brédas, J.-L.; Mohammed, O. F., Pyridine-Induced
Dimensionality Change in Hybrid Perovskite Nanocrystals. Chem.
Mater. 2017, 29, 4393-4400.
76.
Zhou, Z.; Cui, Y.; Deng, H.-X.; Huang, L.; Wei, Z.; Li, J.,
Modulation of electronic and optical properties in mixed halide
perovskites CsPbCl3xBr3(1-x) and CsPbBr3xI3(1-x). Appl. Phys. Lett.
2017, 110, 113901.
1
2
3
4
5
6
7
8
77.
De Roo, J.; Ibáñez, M.; Geiregat, P.; Nedelcu, G.;
Walravens, W.; Maes, J.; Martins, J. C.; Van Driessche, I.; Kovalenko,
M. V.; Hens, Z., Highly Dynamic Ligand Binding and Light
Absorption Coefficient of Cesium Lead Bromide Perovskite
Nanocrystals. ACS Nano 2016, 10, 2071-2081.
61.
Habisreutinger, S. N.; Noel, N. K.; Snaith, H. J.; Nicholas, R.
J., Investigating the Role of 4-Tert Butylpyridine in Perovskite Solar
Cells. Adv. Energy Mater. 2017, 7, 1601079.
78.
Liu, F.; Zhang, Y.; Ding, C.; Kobayashi, S.; Izuishi, T.;
62.
Zhang, J.; Wang, P.; Huang, X.; Xu, J.; Wang, L.; Yue, G.; Lu,
Nakazawa, N.; Toyoda, T.; Ohta, T.; Hayase, S.; Minemoto, T.;
Yoshino, K.; Dai, S.; Shen, Q., Highly Luminescent Phase-Stable
CsPbI3 Perovskite Quantum Dots Achieving Near 100% Absolute
Photoluminescence Quantum Yield. ACS Nano 2017, 11, 10373-
10383.
9
X.; Liu, J.; Hu, Z.; Wang, Q.; Zhu, Y., Polar molecules modify
perovskite surface to reduce recombination in perovskite solar
cells. RSC Adv. 2016, 6, 9090-9095.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
63.
Pan, J.; Sarmah, S. P.; Murali, B.; Dursun, I.; Peng, W.;
Parida, M. R.; Liu, J.; Sinatra, L.; Alyami, N.; Zhao, C.; Alarousu, E.;
Ng, T. K.; Ooi, B. S.; Bakr, O. M.; Mohammed, O. F., Air-Stable Surface-
Passivated Perovskite Quantum Dots for Ultra-Robust, Single- and
Two-Photon-Induced Amplified Spontaneous Emission. J. Phys.
Chem Lett. 2015, 6, 5027-5033.
79.
Wang, C. J.; Chesman, A. S. R.; Jasieniak, J. J., Stabilizing the
cubic perovskite phase of CsPbI3 nanocrystals by using an alkyl
phosphinic acid. Chemical Communications 2017, 53, 232-235.
80.
Hu, H.; Wu, L.; Tan, Y.; Zhong, Q.; Chen, M.; Qiu, Y.; Yang,
D.; Sun, B.; Zhang, Q.; Yin, Y., Interfacial Synthesis of Highly Stable
CsPbX3/Oxide Janus Nanoparticles. J. Am. Chem. Soc. 2018, 140,
406-412.
64.
Zhu, R.; Liu, H.; Shen, L.; Sun, D.; Li, X., Modifying CH 3 NH
3 PbBr 3 nanocrystals with arylamines. J. Phys. Chem. Solids 2017,
103, 164-169.
81.
Li, Z.; Kong, L.; Huang, S.; Li, L., Highly Luminescent and
65.
Zhao, T.; Chueh, C.-C.; Chen, Q.; Rajagopal, A.; Jen, A. K. Y.,
Ultrastable CsPbBr3 Perovskite Quantum Dots Incorporated into a
Silica/Alumina Monolith. Angew. Chem., Int. Ed. 2017, 56, 8134-
8138.
Defect Passivation of Organic–Inorganic Hybrid Perovskites by
Diammonium Iodide toward High-Performance Photovoltaic
Devices. ACS Energy Lett. 2016, 1, 757-763.
82.
Anderson, N. C.; Hendricks, M. P.; Choi, J. J.; Owen, J. S.,
66.
Zuo, L.; Gu, Z.; Ye, T.; Fu, W.; Wu, G.; Li, H.; Chen, H.,
Ligand Exchange and the Stoichiometry of Metal Chalcogenide
Nanocrystals: Spectroscopic Observation of Facile Metal-
Carboxylate Displacement and Binding. J. Am. Chem. Soc. 2013,
135, 18536-18548.
Enhanced Photovoltaic Performance of CH3NH3PbI3 Perovskite
Solar Cells through Interfacial Engineering Using Self-Assembling
Monolayer. J. Am. Chem. Soc. 2015, 137, 2674-2679.
67.
Koh, W.-k.; Park, S.; Ham, Y., Phosphonic Acid Stabilized
83.
Green, M. L. H., A new approach to the formal
Colloidal CsPbX3 (X=Br, I) Perovskite Nanocrystals and Their
classification of covalent compounds of the elements. J. Organomet.
Surface Chemistry. ChemistrySelect 2016, 1, 3479-3482.
Chem. 1995, 500, 127-148.
84.
Mater. Chem. 2010, 20, 5797-5809.
68.
Koscher, B. A.; Swabeck, J. K.; Bronstein, N. D.; Alivisatos,
Green, M., The nature of quantum dot capping ligands. J.
A. P., Essentially Trap-Free CsPbBr3 Colloidal Nanocrystals by
Postsynthetic Thiocyanate Surface Treatment. J. Am. Chem. Soc.
2017, 139, 6566-6569.
85.
ten Brinck, S.; Infante, I., Surface Termination,
Morphology, and Bright Photoluminescence of Cesium Lead Halide
69.
science of nanocrystals. Nat. Mater. 2016, 15, 141-153.
70. Kovalenko, M. V.; Manna, L.; Cabot, A.; Hens, Z.; Talapin,
Boles, M. A.; Ling, D.; Hyeon, T.; Talapin, D. V., The surface
Perovskite Nanocrystals. ACS Energy Lett. 2016, 1, 1266-1272.
86.
Huang, S.; Li, Z.; Kong, L.; Zhu, N.; Shan, A.; Li, L.,
Enhancing the Stability of CH3NH3PbBr3 Quantum Dots by
Embedding in Silica Spheres Derived from Tetramethyl
Orthosilicate in “Waterless” Toluene. J. Am. Chem. Soc. 2016, 138,
5749-5752.
D. V.; Kagan, C. R.; Klimov, V. I.; Rogach, A. L.; Reiss, P.; Milliron, D.
J.; Guyot-Sionnnest, P.; Konstantatos, G.; Parak, W. J.; Hyeon, T.;
Korgel, B. A.; Murray, C. B.; Heiss, W., Prospects of Nanoscience with
Nanocrystals. ACS Nano 2015, 9, 1012-1057.
87.
Foley, B. J.; Girard, J.; Sorenson, B. A.; Chen, A. Z.; Scott
71.
Brown, P. R.; Kim, D.; Lunt, R. R.; Zhao, N.; Bawendi, M. G.;
Niezgoda, J.; Alpert, M. R.; Harper, A. F.; Smilgies, D.-M.; Clancy, P.;
Saidi, W. A.; Choi, J. J., Controlling nucleation, growth, and
orientation of metal halide perovskite thin films with rationally
selected additives. J. Mater. Chem. A 2017, 5, 113-123.
Grossman, J. C.; Bulović, V., Energy Level Modification in Lead
Sulfide Quantum Dot Thin Films through Ligand Exchange. ACS
Nano 2014, 8, 5863-5872.
72.
Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.;
88.
Solvent. Org. Process Res. Dev. 2012, 16, 1273-1278.
89. Yoon, S. J.; Stamplecoskie, K. G.; Kamat, P. V., How Lead
Halide Complex Chemistry Dictates the Composition of Mixed
Halide Perovskites. J. Phys. Chem Lett. 2016, 7, 1368-1373.
Tilstam, U., Sulfolane: A Versatile Dipolar Aprotic
Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A.; Kovalenko, M. V.,
Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X = Cl,
Br, and I): Novel Optoelectronic Materials Showing Bright
Emission with Wide Color Gamut. Nano Lett. 2015, 15, 3692-3696.
73.
Akkerman, Q. A.; D’Innocenzo, V.; Accornero, S.;
90.
McMeekin, D. P.; Sadoughi, G.; Rehman, W.; Eperon, G. E.;
Scarpellini, A.; Petrozza, A.; Prato, M.; Manna, L., Tuning the Optical
Properties of Cesium Lead Halide Perovskite Nanocrystals by
Anion Exchange Reactions. J. Am. Chem. Soc. 2015, 137, 10276-
10281.
Saliba, M.; Horantner, M. T.; Haghighirad, A.; Sakai, N.; Korte, L.;
Rech, B.; Johnston, M. B.; Herz, L. M.; Snaith, H. J., A mixed-cation
lead mixed-halide perovskite absorber for tandem solar cells.
Science 2016, 351, 151-155.
74.
Jing, Q.; Zhang, M.; Huang, X.; Ren, X.; Wang, P.; Lu, Z.,
91.
Zhu, W.; Bao, C.; Li, F.; Yu, T.; Gao, H.; Yi, Y.; Yang, J.; Fu, G.;
Surface passivation of mixed-halide perovskite CsPb(BrxI1-x
)
3
Zhou, X.; Zou, Z., A halide exchange engineering for CH 3 NH 3 PbI
3−x Br x perovskite solar cells with high performance and stability.
Nano Energy 2016, 19, 17-26.
nanocrystals by selective etching for improved stability. Nanoscale
2017, 9, 7391-7396.
75.
Koscher, B. A.; Bronstein, N. D.; Olshansky, J. H.;
92.
Atourki, L.; Vega, E.; Mollar, M.; Marí, B.; Kirou, H.;
Bekenstein, Y.; Alivisatos, A. P., Surface- vs Diffusion-Limited
Mechanisms of Anion Exchange in CsPbBr3 Nanocrystal Cubes
Revealed through Kinetic Studies. J. Am. Chem. Soc. 2016, 138,
12065-12068.
Bouabid, K.; Ihlal, A., Impact of iodide substitution on the physical
properties and stability of cesium lead halide perovskite thin films
CsPbBr3−xIx (0 ≤ x ≤ 1). J. Alloys Compd. 2017, 702, 404-409.
ACS Paragon Plus Environment

Page 13 of 13
Chemistry of Materials
93.
Kulbak, M.; Cahen, D.; Hodes, G., How Important Is the
102.
Leijtens, T.; Eperon, G. E.; Barker, A. J.; Grancini, G.;
Organic Part of Lead Halide Perovskite Photovoltaic Cells? Efficient
CsPbBr3 Cells. J. Phys. Chem Lett. 2015, 6, 2452-2456.
94. Kulbak, M.; Gupta, S.; Kedem, N.; Levine, I.; Bendikov, T.;
Hodes, G.; Cahen, D., Cesium Enhances Long-Term Stability of Lead
Bromide Perovskite-Based Solar Cells. J. Phys. Chem Lett.2016, 7,
167-172.
Zhang, W.; Ball, J. M.; Kandada, A. R. S.; Snaith, H. J.; Petrozza, A.,
Carrier trapping and recombination: the role of defect physics in
enhancing the open circuit voltage of metal halide perovskite solar
cells. Energy Environ. Sci. 2016, 9, 3472-3481.
1
2
3
4
5
6
103.
Stranks, S. D.; Burlakov, V. M.; Leijtens, T.; Ball, J. M.;
Goriely, A.; Snaith, H. J., Recombination Kinetics in Organic-
Inorganic Perovskites: Excitons, Free Charge, and Subgap States.
Phys. Rev. Appl. 2014, 2,034007, 1-8.
95.
Niezgoda, J. S.; Foley, B. J.; Chen, A. Z.; Choi, J. J., Improved
Charge Collection in Highly Efficient CsPbBrI2 Solar Cells with
7
8
9
Light-Induced Dealloying. ACS Energy Lett. 2017, 2, 1043-1049.
104.
Yin, W.-J.; Shi, T.; Yan, Y., Unusual defect physics in
96.
Sutton, R. J.; Eperon, G. E.; Miranda, L.; Parrott, E. S.;
CH3NH3PbI3 perovskite solar cell absorber. Appl. Phys. Lett. 2014,
104, 063903, 1-4.
105.
S.; Ho-Baillie, A.; Huang, S.; Green, M. A.; Seidel, J.; Ahn, T. K.; Seok,
S. I., Beneficial Effects of PbI2 Incorporated in Organo-Lead Halide
Perovskite Solar Cells. Adv. Energy Mater. 2016, 6, 1502104, 1-8.
Kamino, B. A.; Patel, J. B.; Hörantner, M. T.; Johnston, M. B.;
Haghighirad, A. A.; Moore, D. T.; Snaith, H. J., Bandgap-Tunable
Cesium Lead Halide Perovskites with High Thermal Stability for
Efficient Solar Cells. Adv. Energy Mater. 2016, 6, 1502458, 1-6.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Kim, Y. C.; Jeon, N. J.; Noh, J. H.; Yang, W. S.; Seo, J.; Yun, J.
97.
Fang, H.-H.; Protesescu, L.; Balazs, D. M.; Adjokatse, S.;
Kovalenko, M. V.; Loi, M. A., Exciton Recombination in
Formamidinium Lead Triiodide: Nanocrystals versus Thin Films.
Small 2017, 13, 1700673, 1-10.
106.
Sarmah, S. P.; Burlakov, V. M.; Yengel, E.; Murali, B.;
Alarousu, E.; El-Zohry, A. M.; Yang, C.; Alias, M. S.; Zhumekenov, A.
A.; Saidaminov, M. I.; Cho, N.; Wehbe, N.; Mitra, S.; Ajia, I.; Dey, S.;
Mansour, A. E.; Abdelsamie, M.; Amassian, A.; Roqan, I. S.; Ooi, B. S.;
Goriely, A.; Bakr, O. M.; Mohammed, O. F., Double Charged Surface
Layers in Lead Halide Perovskite Crystals. Nano Lett. 2017, 17,
2021-2027.
98.
Yamada, Y.; Nakamura, T.; Endo, M.; Wakamiya, A.;
Kanemitsu, Y., Photocarrier Recombination Dynamics in
Perovskite CH3NH3PbI3 for Solar Cell Applications. J. Am. Chem. Soc.
2014, 136, 11610-11613.
99.
Burschka, J.; Kessler, F.; Nazeeruddin, M. K.; Grätzel, M.,
107.
Owen, J., The coordination chemistry of nanocrystal
Co(III) Complexes as p-Dopants in Solid-State Dye-Sensitized Solar
surfaces. Science 2015, 347, 615-616.
108.
Cells. Chem. Mater. 2013, 25, 2986-2990.
Santomauro, F. G.; Grilj, J.; Mewes, L.; Nedelcu, G.;
100.
Correa-Baena, J.-P.; Tress, W.; Domanski, K.; Anaraki, E.
Yakunin, S.; Rossi, T.; Capano, G.; Al Haddad, A.; Budarz, J.; Kinschel,
D.; Ferreira, D. S.; Rossi, G.; Gutierrez Tovar, M.; Grolimund, D.;
Samson, V.; Nachtegaal, M.; Smolentsev, G.; Kovalenko, M. V.;
Chergui, M., Localized holes and delocalized electrons in
photoexcited inorganic perovskites: Watching each atomic actor
by picosecond X-ray absorption spectroscopy. Struct. Dyn. 2017, 4,
044002, 1-11.
H.; Turren-Cruz, S.-H.; Roose, B.; Boix, P. P.; Grätzel, M.; Saliba, M.;
Abate, A.; Hagfeldt, A., Identifying and suppressing interfacial
recombination to achieve high open-circuit voltage in perovskite
solar cells. Energy Environ. Sci. 2017, 10, 1207-1212.
101.
Xi, H.; Tang, S.; Ma, X.; Chang, J.; Chen, D.; Lin, Z.; Zhong,
P.; Wang, H.; Zhang, C., Performance Enhancement of Planar
Heterojunction Perovskite Solar Cells through Tuning the Doping
Properties of Hole-Transporting Materials. ACS Omega 2017, 2,
326-336.
TOC
ACS Paragon Plus Environment