Impact of Bi3+ Heterovalent Doping in Organic-Inorganic Metal Halide Perovskite Crystals

Article abstract of DOI:10.1021/jacs.7b11125

Intrinsic organic-inorganic metal halide perovskites (OIHP) based semiconductors have shown wide applications in optoelectronic devices. There have been several attempts to incorporate heterovalent metal (e.g., Bi³⁺) ions in the perovskites in an attempt to induce electronic doping and increase the charge carrier density in the semiconductor. It has been reported that inclusion of Bi³⁺ decreases the band gap of the material considerably. However, contrary to the earlier conclusions, despite a clear change in the appearance of the crystal as observed by eye, here we show that the band gap of MAPbBr₃ crystals does not change due the presence of Bi³⁺ in the growth solution. An increased density of states in the band gap and use of very thick samples for transmission measurements, erroneously give the impression of a band gap shift. These sub band gap states also act as nonradiative recombination centers in the crystals.

Full text of DOI:10.1021/jacs.7b11125

Subscriber access provided by UNIV OF NEW ENGLAND ARMIDALE
Communication
The impact of Bi3+ heterovalent doping in organic-
inorganic metal halide perovskite crystals
Pabitra Nayak, Michael Sendner, Bernard Wenger, Zhiping Wang, Kshama Sharma, Alexandra
J Ramadan, Robert Lovrincic, Annemarie Pucci, Perunthiruthy K. Madhu, and Henry J. Snaith
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.7b11125 • Publication Date (Web): 21 Dec 2017
Downloaded from http://pubs.acs.org on December 21, 2017
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 free 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 accessible to all
readers and 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.
Journal of the American Chemical Society 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 4
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
The impact of Bi3+ heterovalent doping in organic-inorganic metal
halide perovskite crystals
9
Pabitra K. Nayaka, Michael Sendnerb,c, Bernard Wengera, Zhiping Wanga, Kshama Sharmad, Alexandra
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
Ramadana, Robert Lovrinčić b,e, Annemarie Puccib,c, P. K. Madhud,f , Henry J. Snaitha *.
aClarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
bInnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
cKirchhoff Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
dTIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad, 500075, India
eInstitute for High Frequency Technology, TU Braunschweig, Schleinizstr. 22, 38106 Braunschweig, Germany
fDepartment of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005, India
Supporting Information Placeholder
responsible for the previous misinterpretation of light absorption
measurements.
ABSTRACT: Intrinsic organicꢀinorganic metal halide perovꢀ
skites (OIHP) based semiconductors have shown wide applicaꢀ
We prepared the undoped and doped MAPbBr3 crystals using
the method reported by Adbelhady and coꢀworkers7. We
confirmed the presence of Bi within the crystal via XPS
measurements on a freshly cleaved doped single crystal (Figure
S1).To avoid any ambiguity, we refer to the doped crystals with
the concentration of Bi3+ salt in the growth solution. As previously
observed, the prepared crystals appear darker as the concentration
of Bi3+ is increased in the growth solution (Figure 1a). We
reproduce the shift in the “onset” published by Abdelhady et al.7
when estimating the absorbance of the crystals from light
transmission measurements (Figure 1b). As we explain hereafter,
the absorption onset should not be mistakenly identified as the
band gap of the material. Due to the thickness of the single
crystals (several mm) and the large above band gap absorption
coefficients for OIHP , there is an undetectable amount of light
transmitted right across the light absorbing region of the crystal,
until an energy significantly below the band gap energy of the
material. Therefore, these simple light transmission measurements
are in fact probing the sub band gap absorptions far in the band
tail13. It is therefore not possible to draw any conclusions about
the band gap from such a measurement alone.
tions in optoelectronic devices. There have been several attempts
to incorporate heterovalent metal (e.g. Bi3+) ions in the perovꢀ
skites in an attempt to induce electronic doping and increase the
charge carrier density in the semiconductor. It has been reported
that inclusion of Bi3+ decreases the bandgap of the material conꢀ
siderably. However, contrary to the earlier conclusions, despite a
clear change in the appearance of the crystal as observed by eye,
here we show that bandgap of MAPbBr3 crystals does not change
due the presence of Bi3+ in the growth solution. Formation of
band gap states and use of a very thick sample for transmission
measurements erroneously give the impression of bandgap shift.
We find that the microstrains and the density of subꢀband gap
states increases due to the inclusion of Bi in the perovskite crystal.
These bandgap states also act as nonꢀradiative recombination
centers in the crystals.
Optoelectronic devices based on organicꢀinorganic metal halide
perovskite (OIHP) have shown tremendous progress in the last
few years in optoelectronic applications, owing to their high
electronic quality1,2. This class of materials is often used as
intrinsic semiconductors in devices3. However, almost all
semiconductor materials, including GaAs, benefit from the ability
to electronically dope, either pꢀ or nꢀtype. There have been several
attempts to dope metal halide perovskite materials by
4,5,6
incorporating isovalent (e.g. Sr2+, Cd2+, Sn2+, Ca2+)
and
heterovalent ions like (Bi3+, Sb3+, In3+)7. Abdelhady et al. reported
that heterovalent doping of methylammonium lead bromide
(MAPbBr3) crystals is possible by introducing Bi3+ ions into the
precursor solution during the crystal growth7. Abdelhady et al.
appeared to observe a bandgap narrowing. The band gap
narrowing has also been reported for the CsPbBr3 and MAPbCl3
8,9
crystals with Bi3+ doping
and also for Cs2AgBiBr6 with Tl+
Figure 1. (a) Picture of doped and undoped MAPbBr3 single crysꢀ
tals. (i) pure MAPbBr3, (ii) MAPbBr3 doped with 1 % Bi3+, (iii)
MAPbBr3 doped with 5% Bi3+ and (iv) MAPbBr3 doped with
10% Bi3+. Scale bar: 2 mm. (b) Normalized absorbance spectra of
the crystals. Eabs* = absorption onset
doping10. In OIHPs, a change in band gap is associated with the
change in the crystal lattice parameters,10,11 typically inducing a
change in the leadꢀhalide octahedral tilting angle12. In the case of
Bi3+ doped MAPbBr3 crystals, no such change in crystal lattice
parameters has been observed7,. Herein, we show that doping with
Bi3+ does not change the bandgap of MAPbBr3, but induces a
significant increase in the subꢀband gap density of states,
Spectroscopic ellipsometry is an effective tool to estimate the
above band gap optical properties of OIHP crystals13. Here, we
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 4
perform such measurements upon our range of Bi3+ doped MAPꢀ
fuse reflectance measurements from powdered samples are also
subject to the same errors as transmission measurements16.
bBr3 crystals. We show the measured and modeled ellipsometry
spectra in Figure S2. We fitted those spectra using the Elliot modꢀ
el14 to estimate the exciton binding energy (Rex) and the bandgap
(Eg) from the continuum part of the spectrum. In Figure 2a, we
show the experimentally determined absorption coefficients for
the MAPbBr3 crystal and the crystal doped with 5% Bi3+ as well
as the fittings using the Elliot model. The step function for the
continuum part and delta function for the excitonic transition are
broadened by convolution with Gaussian functions, σcont. and σex
13. In Figure S3 we provide the graphs for all the crystals, and in
Table S2, we provide the values of Eg, Rex, σcont. and σex. We find
that the Eg values of all crystals are almost constant in the range
2.383 eV to 2.389 eV. The change we see is within the error of
our fittings which is ± 15 meV, hence we conclude that there is no
significant change in the bandgap of the material after the Bi3+
doping. However, we note that the broadening factors (σcont. and
σex) do increase after the doping. The broadening could be an
indication of increased energetic disorder present in the system.
1
2
3
4
5
6
7
8
To investigate the effect of the presence of Bi3+ on the lattice
vibrations of MAPbBr3, we performed FarꢀIR measurements on
the crystals. In Figure S6 we show the resulting reflection spectra
for the undoped and Biꢀdoped MAPbBr3 crystals. The abrupt reꢀ
flectance feature we observe in this region of the spectrum, is due
to the frequency of light being close to the vibrational frequency
of the ions in the crystal, which prevents the propagation of light
through the crystal at this frequency. We observe here to be very
similar for the three investigated single crystals, and in agreement
with a recent publication17. We further analyzed the spectra by
using a model based on a Gervais oscillator17,18. We do not deterꢀ
mine significant differences between the fitted resonance frequenꢀ
cies nor the damping constant, as we show in Table S3. As there
is no change in the far IR features due to the doping, we anticipate
that the upper limit for mobility at the room temperature still reꢀ
mains the same i.e. ~200cm2/V.s 17. Moreover, the presence of the
band gap states due to Bi doping would reduce the mobility value
further. Therefore, a mobility value of 1250 cm2/Vs determined
by Abdelhady et al. for the doped crystals is put into question (See
SI)
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
(a)
MAPbBr3
Experimental
Fitted
Excitonic part
Continuum part
MAPbBr3-5% Bi
(b)
MAPbBr3-1% Bi
MAPbBr3-5% Bi
MAPbBr3-10% Bi
104
5.4
3.6
1.8
0.0
To further analyze the influence of the Bi3+ doping we examined
the molecular vibrations of the crystals in the midꢀinfrared specꢀ
tral range, by means of spectroscopic ellipsometry. We included
the optical parameters which we determined in the farꢀinfrared
spectral range, into the optical model based on Glaser et al.19 We
show the optical fit of the ellipsometry spectra with an isotropic
model in Figure S7 along with the resulting dielectric functions of
the undoped MAPbBr3 and the 10% Bi3+ doped MAPbBr3 single
crystal. We observe a very similar imaginary part of the dielectric
function for the highest doped crystal and the undoped crystal.
The vibrations are excited at the same energies as in the undoped
case. We notice a spectral broadening in the region of the NH
stretching vibrations around 3200 cmꢀ1 in the doped sample (Figꢀ
ure S8), which indicates a higher disorder since these vibrations
102
100
MAPbBr3
5.4
3.6
1.8
0.0
2.1
2.2
2.3
2.4
2.5
2.6
1.8
2.0
2.2
2.4
Photon energy [eV]
Photon energy [eV]
Figure 2. (a) Absorption spectra in the band edge region for a
MAPbBr3 single crystal (bottom) and a MAPbBr3 single crystal
with 5% Bi doping (top). (b) Combined absorption spectra from
ellipsometry data (top part) and the UVꢀvis transmission data
(bottom part). The dashed lines are the guides to the eye only.
are very sensitive to the dielectric background 19,20
.
We also determine the bandgap of the crystals using Taucꢀplot
method for a direct bandgap material. The band gap seems to
decrease by 30 meV (Figure S4) on doping
0.8
MAPbBr3- 10 % Bi
002
002
001
001
(a)
003 (b)
MAPbBr3- 5 % Bi
003
0.6
0.4
0.2
MAPbBr3- 1 % Bi
002
002
001
001
Our observation of negligible change in the band gap is in contrast
7
003
MAPbBr3
to reported values in the literature , where a reduction of the
bandgap of 280 meV was estimated from the absorption spectra
measured in light transmission mode. As we mentioned earlier,
the band gap estimated from the normalized absorbance plot of
strongly absorbing single crystals (Figure 1) can be erroneous due
to the long optical path in a thick crystal. To correctly represent
the absorption spectra, we combine the absorption coefficients (α)
obtained from ellipsometry and α calculated from total transmitꢀ
tance TT and total reflectance RT. (Figure 2b). As we show in Figꢀ
ure 2b, although the bandgap remains the same, the absorption tail
increases at lower energies with the presence of Bi3+ in the growth
solution. The exponential slope in the subꢀband gap density of
states, quantified by the Urbach energy (Eu), can be used as metric
to gauge the energetic disorder in the crystal. For the pristine crysꢀ
tal, we determine an Urbach energy of ~19 meV compared to 50ꢀ
55 meV that of the doped crystals. To further confirm, we preꢀ
pared Bi3+ doped thinꢀfilms of MAPbBr3 and measured the abꢀ
sorbance spectra. We see no significant change in the absorption
onset values (Figure S5).
003
10 15 20 25 30 35 40 45 50
0
2
4
6
8
10
ο
Bi concentration [%]
2θ
[
]
Figure 3. (a) XRD patterns of undoped and Bi doped MAPbBr3
crystals, (b) Calculated microstrain of samples with different conꢀ
centrations of Bismuth doping.
To identify the impact of Bismuth incorporation on the crystal
structure of MAPbBr3 single crystals, we performed Xꢀray difꢀ
fraction (XRD) measurement. In Figure 3a we show the 2θ/ω
scans of the pristine MAPbBr3 single crystal and MAPbBr3 single
crystals with different Bi3+ doping concentrations.The average Biꢀ
Br bond length in BiBr63ꢀ octahedra (2.87 Å, calculated from the
axial and equatorial bonds 21) is very close to the average PbꢀBr
bond length (2.97Å) in a MAPbBr3 single crystal22. Though we
expect a very small change in the in the lattice parameter due to
the incorporation of Bi, we do not determine a resolvable shift in
the XRD peaks in our measurement (Figure S9) or see any new
diffraction peaks in the XRD patterns due to doping.
We note that several works claiming a band gap narrowing of
halide perovskites due to doping have utilized diffuse reflectance
measurements for the band gap determination10,15. However, difꢀ
ACS Paragon Plus Environment

Page 3 of 4
Journal of the American Chemical Society
We hypothesize that the Bismuth is uniformly distributed
and the thickness of the crystals13. Previous reports on Bi3+ doping
of OIHP have underestimated this effect, and have thus reported
band gap reductions that we can’t reproduce when using appropriꢀ
ate measurement techniques such as ellipsometry. We note that
such erroneous band gap shifts have been also reported for unꢀ
doped perovskite single crystals or thick polycrystalline samples
in several studies published in leading journals (see SI). The oriꢀ
gins of such (apparent) band gap shifts (reported to be an unꢀ
solved problem26,27) can be explained considering the band edge
throughout the crystal, but its presence, either in the final crystals
or simply during the crystallization process, is primarily
disrupting the crystalline order and increasing the electronic
disorder, rather than resulting in a systematic shift in the crystal
structure. The reduced crystalline order may be detectable in the
form of nonꢀuniform strain (microstrain) in the MAPbBr3 crystals,
induced by crystal imperfections/structural defects including
dislocations, vacancies, stacking faults, etc.23. We quantify the
extent of microstrain in our perovskite crystals by analyzing the
peak broadening in the diffraction patterns according to the
modified WilliamsonꢀHall method (see SI) .23,24 Consistently, we
determine the microstrain in the crystals to increase upon doping
(Figure 3b and Figure S10). Furthermore, we observe gradual
broadening in the rocking curves (ω scans) of crystals with
increasing doping (Figure S11) which indicates distortions in the
crystal planes across the crystals.
1
2
3
4
5
6
7
8
13
tail absorption in thick samples while the band gap value reꢀ
mains constant.
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
From our experimental work, we are now able to provide a more
detailed picture of the doping of MAPbBr3 single crystals by bisꢀ
muth. The absence of band gap reduction, combined with an inꢀ
creased energetic disorder points towards the introduction of deꢀ
fects in the perovskite by the presence of Bi3+ ions in the growth
solution. In addition, the strong quenching of the photoluminesꢀ
cence and decrease in EQE of indicates that the electronic states
introduced by the dopants are detrimental to the optoelectronic
quality of the material.
In order to obtain information about the uniformity of the chemiꢀ
cal environment around the Pb2+ center and the protons of meꢀ
thylammonium, we performed solidꢀstate 207Pb NMR and 1H
NMR of the crystals. In Figure 4a, we show the 207Pb NMR specꢀ
tra of the undoped and doped crystals. We observe that the NMR
spectrum is broadened for the doped crystal, implying a variable
environment around the Pb and MA ions. For the 207Pb centers,
the broadening is probably due to the increased disorder in the
crystal as the chemical shift of nuclei is sensitive to the local
structural distortions25. We also see a similar broadening of the 1H
NMR spectrum (Figure S12)
In conclusion, we have shown that bandgap narrowing does not
occur in the MAPbBr3 crystals following the incorporation of Bi3+
in the growth solution. The apparent effect of the colour change,
is due to the increased number of defect states and a significant
increase in the subꢀband gap density of states. The Biꢀdoped crysꢀ
tals have higher levels of microstrain, increased electronic disorꢀ
der and reduced carrier lifetime and PL efficiency, due to inꢀ
creased nonꢀradiative recombination. Our study highlights the
challenges with heterovalent doping, particularly with Bi, of
OIHP semiconductors. More studies with different dopants will
gauge the usefulness of such an approach in order to control the
structural and electronic properties of OIHP.
MAPbBr
(a)5
3
4
(b)
MAPbBr -10% Bi
106
3
3
105
MAPbBr
3
2
MAPbBr -5% Bi
3
104
103
1
0
1000
950
900
850
800
750
700
2.0
2.2
2.4
2.6
2.8
Photon energy [eV]
We finally note that a recent publication identified bisꢀ
muth doping of CsPbI3 as a feasible route to increase the structural
stability, induce a 174 meV lowering of the absorption edge, and
increase the PL efficiency and photovoltaic solar energy converꢀ
sion efficiency28. This recent publication is inconsistent with our
findings here, and indicates that further work is still required to
understand the impact of heterovalent doping upon OIHP.
Chemical shift [ppm]
Figure 4. (a) 207Pb NMR spectrum of the undoped and Biꢀdoped
MAPbBr3 crystals. (b) Steadyꢀstate PL spectrum of MAPbBr3 and
Biꢀdoped MAPbBr3.
After establishing the impact of bismuth doping on the energetic
disorder and microstrains, we looked for the impact on the photoꢀ
luminescence (PL) properties of the materials. In Figure 4b we
show the PL spectrum of the crystals and the timeꢀresolved PL
decays in Figure S13. We find that the PL intensity is quenched
by >99 % in the doped crystals. We also observe a lowering of the
average PL decay lifetime in the presence of Bi3+ doping, via
timeꢀresolved photoluminescence (TRPL) decay measurements.
All our findings are consistent with the presence of bismuth introꢀ
ducing defect states in the crystal, which facilitating unfavorable
nonꢀradiative recombination, thereby lowering the PL intensity
and PL lifetime.
Supporting Information
AUTHOR INFORMATION
Corresponding Author: Henry.Snaith@physics.ox.ac.uk
ACKNOWLEDGMENT
This work is supported by the EPSRC UK. MS and RL
acknowledge the InterPhase project from BMBF (FKZ
13N13656, 13N13657). BW acknowledges Marie Skłodowskaꢀ
Curie actions (706552ꢀAPPEL). We thank Sebastian Beck and
Nobuya Sakai for their assistance in UVꢀvis absorption measureꢀ
ments.
To understand the effect of doping on the charge transport, we
prepared solar cells with the following configuration
FTO/SnO2/MAPbBr3 (Biꢀdoped)/SpiroꢀOmeTAD/Ag. We measꢀ
ured the EQE of the devices and present the data in the Figure
S14. We find EQE drops with increased concentration of Bi in the
MAPbBr3 films. This finding indicates that the introduction Bi
introduces traps in the thinfilm which in turn reduces the carrier
collection efficiency. In addition, we do not see any shift in the
onset of the EQE spectrum which reaffirms our conclusion that
the introduction of Bi does not change the bandgap of the material
REFERENCES
(1)
Manser, J. S.; Christians, J. A.; Kamat, P. V. Chem. Rev. 2016,
116 (21), 12956.
(2)
(3)
Stranks, S. D.; Snaith, H. J. Nat. Nanotechnol. 2015, 10 (5), 391.
Edri, E.; Kirmayer, S.; Mukhopadhyay, S.; Gartsman, K.;
Hodes, G.; Cahen, D. Nat. Commun. 2014, 5, ncomms4461.
Klug, M. T.; Osherov, A.; Haghighirad, A. A.; Stranks, S. D.;
Brown, P. R.; Bai, S.; Wang, J. T.ꢀW.; Dang, X.; Bulović, V.;
Snaith, H. J.; Belcher, A. M. Energy Environ. Sci. 2017, 10 (1),
236.
(4)
The estimation of the bandgap from light transmission measureꢀ
ments can be difficult due to the strong absorption coefficients
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 4
(5)
Lau, C. F. J.; Zhang, M.; Deng, X.; Zheng, J.; Bing, J.; Ma, Q.;
Lovrinčić, R. Mater. Horiz. 2016, 3 (6), 613.
Kim, J.; Hu, L.; Green, M. A.; Huang, S.; HoꢀBaillie, A. ACS
Energy Lett. 2017, 2319.
Hao, F.; Stoumpos, C. C.; Chang, R. P. H.; Kanatzidis, M. G. J.
Am. Chem. Soc. 2014, 136 (22), 8094.
Abdelhady, A. L.; Saidaminov, M. I.; Murali, B.; Adinolfi, V.;
Voznyy, O.; Katsiev, K.; Alarousu, E.; Comin, R.; Dursun, I.;
Sinatra, L.; Sargent, E. H.; Mohammed, O. F.; Bakr, O. M. J.
Phys. Chem. Lett. 2016, 7 (2), 295.
Miao, X.; Qiu, T.; Zhang, S.; Ma, H.; Hu, Y.; Bai, F.; Wu, Z. J.
Mater. Chem. C 2017, 5 (5), 4931.
Zhang, Z.; Ren, L.; Yan, H.; Guo, S.; Wang, S.; Wang, M.; Jin,
K. J. Phys. Chem. C 2017, 121 (32), 17436.
Slavney, A. H.; Leppert, L.; Bartesaghi, D.; GoldꢀParker, A.;
Toney, M. F.; Savenije, T. J.; Neaton, J. B.; Karunadasa, H. I. J.
Am. Chem. Soc. 2017, 139 (14), 5015.
Eperon, G. E.; Stranks, S. D.; Menelaou, C.; Johnston, M. B.;
Herz, L. M.; Snaith, H. J. Energy Environ. Sci. 2014, 7 (3), 982.
Filip, M. R.; Eperon, G. E.; Snaith, H. J.; Giustino, F. Nat.
Commun. 2014, 5, 5757.
Wenger, B.; Nayak, P. K.; Wen, X.; Kesava, S. V.; Noel, N. K.;
Snaith, H. J. Nat. Commun. 2017, 8 (1), 590.
(18)
(19)
Gervais, F.; Piriou, B. J. Phys. C Solid State Phys. 1974, 7 (13),
2374.
1
2
3
4
5
6
7
8
(6)
(7)
Glaser, T.; Müller, C.; Sendner, M.; Krekeler, C.; Semonin, O.
E.; Hull, T. D.; Yaffe, O.; Owen, J. S.; Kowalsky, W.; Pucci, A.;
Lovrinčić, R. J. Phys. Chem. Lett. 2015, 6 (15), 2913.
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. Chem. Mater. 2015, 27
(22), 7835.
Bi, W.; Leblanc, N.; Mercier, N.; AubanꢀSenzier, P.; Pasquier,
C. Chem. Mater 2009, 21, 4099.
Rakita, Y.; Cohen, S. R.; Kedem, N. K.; Hodes, G.; Cahen, D.
MRS Commun. 2015, 5 (4), 623.
Pramanick, A.; Wang, X. P.; Hoffmann, C.; Diallo, S. O.;
Jørgensen, M. R. V.; Wang, X.ꢀL. Phys. Rev. B 2015, 92 (17),
174103.
Zhao, Y.; Zhang, J.; IUCr. J. Appl. Crystallogr. 2008, 41 (6),
1095.
Brouwer, D. H.; Brouwer; H., D. In Encyclopedia of Magnetic
Resonance; John Wiley & Sons, Ltd: Chichester, UK, 2008.
Huang, J.; Yuan, Y.; Shao, Y.; Yan, Y. Nat. Rev. Mater. 2017, 2
(7), 17042.
Adinolfi, V.; Peng, W.; Walters, G.; Bakr, O. M.; Sargent, E. H.
Adv. Mater. 2017, 1700764.
(20)
(8)
(21)
(22)
(23)
(9)
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
(10)
(11)
(12)
(13)
(24)
(25)
(26)
(27)
(28)
(14)
(15)
Elliott, R. J. Phys. Rev. 1957, 108 (6), 1384.
Du, K. Z.; Wang, X.; Han, Q.; Yan, Y.; Mitzi, D. B. ACS
Energy Lett. 2017, 2 (10), 2486.
Murphy, A. B. Sol. Energy Mater. Sol. Cells 2007, 91 (14),
1326.
Sendner, M.; Nayak, P. K.; Egger, D. A.; Beck, S.; Müller, C.;
Epding, B.; Kowalsky, W.; Kronik, L.; Snaith, H. J.; Pucci, A.;
(16)
(17)
Hu, Y.; Bai, F.; Liu, X.; Ji, Q.; Miao, X.; Qiu, T.; Zhang, S. ACS
Energy Lett. 2017, No. 2, 2219.
TOC Figure
ACS Paragon Plus Environment