Phase Engineering of Cesium Manganese Bromides Nanocrystals with Color-Tunable Emission

Article abstract of DOI:10.1002/anie.202105413

For display applications, it is highly desirable to obtain tunable red/green/blue emission. However, lead-free perovskite nanocrystals (NCs) generally exhibit broadband emission with poor color purity. Herein, we developed a unique phase transition strategy to engineer the emission color of lead-free cesium manganese bromides NCs and we can achieve a tunable red/green/blue emission with high color purity in these NCs. Such phase transition can be triggered by isopropanol: from one dimensional (1D) CsMnBr₃ NCs (red-color emission) to zero dimensional (0D) Cs₃MnBr₅ NCs (green-color emission). Furthermore, in a humid environment both 1D CsMnBr₃ NCs and 0D Cs₃MnBr₅ NCs can be transformed into 0D Cs₂MnBr₄?2 H₂O NCs (blue-color emission). Cs₂MnBr₄?2 H₂O NCs could inversely transform into the mixture of CsMnBr₃ and Cs₃MnBr₅ phase during the thermal annealing dehydration step. Our work highlights the tunable optical properties in single component NCs via phase engineering and provides a new avenue for future endeavors in light-emitting devices.

Full text of DOI:10.1002/anie.202105413

Angewandte
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How to cite:
International Edition: doi.org/10.1002/anie.202105413
German Edition: doi.org/10.1002/ange.202105413
Nanocrystals
Phase Engineering of Cesium Manganese Bromides Nanocrystals with
Color-Tunable Emission
Qingkun Kong, Bin Yang,* Junsheng Chen, Ruiling Zhang, Siping Liu, Daoyuan Zheng,
Hongling Zhang, Qingtong Liu, Yiying Wang, and Keli Han*
Abstract: For display applications, it is highly desirable to
obtain tunable red/green/blue emission. However, lead-free
perovskite nanocrystals (NCs) generally exhibit broadband
emission with poor color purity. Herein, we developed
a unique phase transition strategy to engineer the emission
color of lead-free cesium manganese bromides NCs and we can
achieve a tunable red/green/blue emission with high color
purity in these NCs. Such phase transition can be triggered by
isopropanol: from one dimensional (1D) CsMnBr3 NCs (red-
color emission) to zero dimensional (0D) Cs3MnBr5 NCs
(green-color emission). Furthermore, in a humid environment
both 1D CsMnBr3 NCs and 0D Cs3MnBr5 NCs can be
transformed into 0D Cs2MnBr4·2H2O NCs (blue-color emis-
sion). Cs2MnBr4·2H2O NCs could inversely transform into the
mixture of CsMnBr3 and Cs3MnBr5 phase during the thermal
annealing dehydration step. Our work highlights the tunable
optical properties in single component NCs via phase engineer-
ing and provides a new avenue for future endeavors in light-
emitting devices.
metal halide NCs exhibit broadband PL with poor color
purity due to the strong carrier-phonon coupling.[19,20] For
display applications, it is attractive to obtain NCs with color-
tunable emission and high color purity. Various preparation
methods (e.g. doping, surface passivation, or A site substi-
tuted with organic molecule) show great potential to manip-
ulate emission color of lead-free halide perovskites NCs.[13–17]
However, their tunability for the color range and the color
purity is limited.[21–23] So far, to the best of our knowledge,
tunable red/green/blue color emission with high color purity
has not been achieved for lead-free metal halide NCs.
Herein, for the first time, we report a tunable pure-color
red/green/blue emission in lead-free metal halide NCs by
modulating the crystal field strengths and coordination sites
of cesium manganese bromides NCs through phase engineer-
ing. We develop a unique strategy for the selective synthesis
of 1D CsMnBr3 NCs and 0D Cs3MnBr5 NCs with pure phase.
1D CsMnBr3 NCs with an octahedral coordination give a red
emission. While 0D Cs3MnBr5 NCs with a tetrahedral coor-
dination exhibit a green emission with a high PLQY of 48%
and full-width at half-maximum (FWHM) of 43 nm. Further-
more, we found that water could trigger phase transformation
process of 1D CsMnBr3 NCs and 0D Cs3MnBr5 NCs to form
stable 0D Cs2MnBr4·2H2O NCs with blue emission.
C
esium lead halide perovskite CsPbX3 (X: Cl, Br, I)
nanocrystals (NCs) with narrow photoluminescence (PL)
emission band have been shown to be good emitters of red,
green and blue light.[1–11] Major issues about these lead halide
perovskites are their toxicity and poor stability.[12] This has
triggered the development of lead-free metal halide perov-
skite NCs. Different lead-free metal halide perovskites NCs
with structure similar to lead halide perovskites have been
reported, such as ABX3, A3B2X9, A2B(I)B(III)X6 double
perovskite and A2BX6, where A is a cation (Cs+, Rb+ or
Cesium manganese halide NCs were prepared by using
a hot-injection method (details in SI). The crystal structure
can be controlled by the molar ratio between Cs(OAc) and
Mn(OAc)2 during the hot-injection (Figure 1a). Typically,
when Cs(OAc)-to-Mn(OAc)2 ratio is 1:1.35, 1D CsMnBr3
NCs are formed. XRD patterns of the as-prepared NCs are
consistent with that of standard CsMnBr3 (PDF card No. 70-
1449). Furthermore, the phase structure of CsMnBr3 NCs is
also confirmed by the Rietveld method (Figure 1b). Refine-
ments suggest that CsMnBr3 NCs have a perovskite structure
with the space group of P63/mmc and cell parameters (a =
7.641 ꢀ, b = 7.641 ꢀ, c = 6.494 ꢀ, a = 908, b = 908, g = 1208,
as listed in Table S1). Each Mn atom is coordinated by six Br
atoms, in which three Br atoms share the plane that bridges
CH3NH3 ), B is a lead-free metallic cation (Ag+, Sn2+, Bi3+,
+
Sb3+, Sn4+, Zr4+, etc.).[13–18] However, most of these lead-free
[*] Q. Kong, R. Zhang, S. Liu, D. Zheng, H. Zhang, Q. Liu, Y. Wang,
Prof. Dr. K. Han
Institute of Molecular Sciences and Engineering, Institute of Frontier
and Interdisciplinary Science, Shandong University
Qingdao 266237 (P. R. China)
4À
E-mail: klhan@dicp.ac.cn
the other adjacent Mn atoms. Plane sharing MnBr6 units
form 1D MnBr3 chains and Cs+ ions are located between the
chains. Transmission electron microscopy (TEM) image
demonstrates that CsMnBr3 NCs have an average edge
length of 18.9 Æ 3.2 nm (Figures 1c,d). The high-resolution
(HR) TEM image of CsMnBr3 NCs reveals high crystallinity
with clear lattice spacing values of 0.208 nm, which is in good
agreement with the (031) plane of CsMnBr3 crystal (Fig-
ure 1e). The chemical compositions of the NCs were checked
by energy dispersive X-ray spectroscopy (EDS) and the
inductively coupled plasma optical emission spectrometry
B. Yang, J. Chen, Prof. Dr. K. Han
State Key Laboratory of Molecular Reaction Dynamics, Dalian
Institute of Chemical Physics, Chinese Academy of Sciences
Dalian 116023 (P. R. China)
E-mail: yangbin@dicp.ac.cn
B. Yang, Prof. Dr. K. Han
University of the Chinese Academy of Sciences
Beijing 100039 (P. R. China)
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.202105413.
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Figure 1. (a) Illustration of the formation process of CsMnBr3 NCs and Cs3MnBr5 NCs. Rietveld refinement XRD patterns of (b) CsMnBr3 NCs and
XRD pattern of (f) as-prepared Cs3MnBr5 NCs. The observed data, calculation data, Bragg position and their difference are depicted in Figure 1b
with black cross, red solid line, green line and blue solid line, respectively. TEM images of the obtained (c) CsMnBr3 NCs and (g) as-prepared
Cs3MnBr5 NCs. Size distribution histograms of (d) CsMnBr3 NCs and (h) as-prepared Cs3MnBr5 NCs. HRTEM images of a single (e) CsMnBr3
NCs and (i) as-prepared Cs3MnBr5 NCs.
(ICP-OES). The results reveal that the elements are evenly
distributed in CsMnBr3 NCs (Figure S1) and the actual Cs/Mn
molar ratio is 0.9:1 (Table S2), which is consistent with the
stoichiometry (1:1). These results suggest the successful
synthesis of CsMnBr3 perovskite NCs.
260 nm, which can be assigned to the low spin-forbidden
transition from A1 to A2 of Mn2+. Upon photoexcitation at
260 nm, CsMnBr3 NCs show a red emission with peak
position at 660 nm with FWHM of 91 nm and PLQY of
11%. The PL excitation (PLE) spectrum matches with the
absorption spectrum. These peaks typically arise from the d-d
transitions of octahedrally coordinated Mn2+ ions.[24]
CsMnBr3 NCs show the same PL spectra with different
excitation wavelengths and identical TRPL decays at differ-
ent emission wavelengths. This suggests the different excited
states generated with different excitation wavelengths funnel
to the same emission state 4T1 (Figures S2 and S3), then
6
4
On the other hand, 0D Cs3MnBr5 NCs can be obtained by
changing the Cs-to-Mn molar feed ratio to 3:1.25 in the
precursor solution. The XRD patterns of the as-prepared NCs
are consistent with that of standard Cs3MnBr5 (PDF card No.
71-1416, Figure 1 f). The structure retrieve analysis reveals
that Cs3MnBr5 NCs belong to space group of I4/mcm
(Figure 3a) and have unit cell of a = 9.598 ꢀ, b = 9.598 ꢀ,
c = 15.567 ꢀ, a = 908, b = 908, g = 908 (Table S3). In this
structure, each Mn2+ site is bonded to four bromine atoms,
forming a [MnBr4] regular tetrahedron geometry. [MnBr4]
unites are distributed along the c-axis direction and are
separated by Cs+. TEM image shows that the as-prepared
Cs3MnBr5 NCs have an average size of 15.5 Æ 1.7 nm and
a lattice distance of 0.178 nm, corresponding to the (251)
crystal plane (Figures 1g–i). It is noted that the as-prepared
Cs3MnBr5 NCs may mix with a small amount of CsMnBr3,
which is hard to distinguish by only using powder XRD
(Discussed as below).
4
a transition from T1 to the ground state 6A1 leads to the red
emission. Temperature-dependent PL spectra (80–300 K) was
further performed to study the optical properties (Figures S4
and S5). With decreasing temperature, the emission intensity
gradually increases, which is resulted from a decrease in
phonon-related nonradiative decay.[25,26] A blue shift of the
PL maximum is also observed with increasing temperature,
which ascribes to the decrease in crystal-field strength and
smaller splitting energy of the excited state caused by thermal
expansion.[26,27] As shown in Figure 2b, the TR-PL spectrum
of CsMnBr3 NCs can be well fitted by a double-exponential
function at room-temperature, yielding two lifetimes (t1 =
8.28 ms and t2 = 206.48 ms) with average lifetime of 133.6 ms,
while the PL decay prolongs at low temperature (Figure S5),
Next, optical properties of as-prepared CsMnBr3 NCs and
Cs3MnBr5 NCs are investigated. As shown in Figure 2a,
CsMnBr3 NCs show a strong absorption peak at around
2
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Cs3MnBr5 structure. TR-PL results show
that the 520 nm emission band has an
average lifetime of 31.4 ms (Figure 2d).
The relative short lifetime indicates that
the non-radiative recombination is domi-
nant in the as-prepared NCs, which results
in low PLQY of 6%.
For the 660 nm emission band, both the
PL and PLE (Figure S7) spectra are similar
to that of CsMnBr3 NCs (Figure 2a),
indicating that small amounts of CsMnBr3
NCs may exist in the Cs3MnBr5 NCs, while
it is hard to distinguish from XRD patterns.
In addition, emission band at 660 nm
shows two lifetimes (94.11 ms and
298.46 ms) with an average lifetime of
121.06 ms (Figure 2d). The TRPL decay
curves of CsMnBr3 NCs recorded at
660 nm show an excitation wavelength
dependence (Figure S8). Excited states
pumped by light with short wavelengths
(high energy) show faster PL decay due to
increased decay channels in high energy
states compared to that in excited states
pumped by light with longer wavelengths.
Upon the same excitation wavelength, the
as-prepared Cs3MnBr5 NCs at 660 nm
emission band show similar PL lifetimes
to that of the CsMnBr3 NCs (Figure 2d and
Figure 2. UV–Vis absorption, PLE, and PL spectra of (a) CsMnBr3 NCs and (c) as-prepared
Cs3MnBr5 NCs, respectively. The insets show the colloidal NCs under 254 nm and 365 nm
UV light excitation, respectively. TR-PL decay curves of (b) CsMnBr3 NCs and (d) as-
prepared Cs3MnBr5 NCs at different emission wavelengths (520 nm and 660 nm) at 300 K.
which can be ascribed to the decreased non-radiative
recombination at low temperature. The long lifetime with
microsecond time scale is similar to CsMnBr3 single crys-
tals.[28,29] We also noted that Bakrꢁs et al. recently reported
CsMnBr3 NCs with picosecond lifetime.[30] This may be due to
PL lifetime of the Mn2+ d-d transitions is sensitive to the Mn-
Mn distance, and the PL lifetime can be tuned from a few
nanoseconds to milliseconds depending upon the Mn-Mn
distance.[30–32] In our work, the Mn-Mn distance in the
CsMnBr3 NCs along the c-axis is 3.24 ꢀ, which is longer
compared with Bakrꢁs report (2.7 ꢀ).[30] The elongated Mn-
Mn distance could lead to a coupled vibrionic state like self-
trapped exciton, which is the cause of long microsecond scale
lifetime.[33] The optical properties of CsMnBr3 NCs with
different Mn-Mn distances need further in-depth study, which
is beyond the scope of this paper.
Figure S8). These results confirm the co-existence of the
CsMnBr3 and Cs3MnBr5 phases in the as-prepared Cs3MnBr5
NCs. Hereinafter, we will combine the spectroscopy evidence
with the XRD results to determine the phase transition of
cesium manganese bromides NCs.
The pure-phase Cs3MnBr5 NCs can be obtained by
immersing the as-prepared Cs3MnBr5 NCs in isopropanol
for 5.5 h (details in SI). As one can see isopropanol treated
Cs3MnBr5 NCs show a single emission band (at 520 nm) with
a small FWHM of 43 nm, while the 660 nm emission band is
disappeared (Figure 3b and Figure S9a). It is noted that the
green emission (PLQY of 48%) is improved compared to the
as-prepared Cs3MnBr5 NCs, suggesting the non-radiative
transition has been suppressed after the isopropanol treat-
ment. In addition, TEM images display that the size of
Cs3MnBr5 NCs gradually increased to ꢀ 51 nm after the
isopropanol treatment (Figure S10), which is larger compared
to the as-prepared Cs3MnBr5 NCs (Figures 3d,e). This may be
related to the re-growth of NCs during the phase transition
from CsMnBr3 to Cs3MnBr5. We also noted that the
isopropanol treated Cs3MnBr5 NCs exhibit sharper XRD
pattern than as-prepared Cs3MnBr5 NCs (Figures 1 f and 3a).
This indicates the Cs3MnBr5 NCs from isopropanol treatment
have higher crystalline quality than the as-prepared Cs3MnBr5
NCs. After isopropanol treatment, TRPL results indicate that
the green emission shows a prolonged PL lifetime (Figure 3c
and Figure S9b), which ascribe to the decreased nonradiative
recombination ratio due to improved crystal quality. So the
improved PL properties of isopropanol treated NCs may be
The optical properties of the as-synthesized Cs3MnBr5
NCs are also studied. The as-prepared NCs exhibit dual
emission band at 520 nm and 660 nm upon excitation at
280 nm (Figure 2c). For the green emission band at 520 nm,
which can be ascribed to the metal-centred d–d transition of
the Mn2+ ion with a tetrahedral coordination geometry.[34–36]
As in different crystal field strengths, the luminescence of
Mn2+ varies in a large range. In the weak field of tetrahedron
coordination geometry, the luminescence of Mn2+ is usually
green, while in the strong field of octahedron coordination
geometry, the luminescence of Mn2+ is red.[31,37] Three
structured bands at 280, 365, and 460 nm are observed in
the PLE spectrum at emission of 520 nm. The three bands
4
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Figure 3. Rietveld refinement XRD patterns of (a) Cs3MnBr5 NCs. The observed data, calculation data, Bragg position and their difference are
depicted with black cross, red solid line, green line and blue solid line. UV–Vis absorption, PLE, and PL spectra of (b) Cs3MnBr5 NCs. The insets
show a photograph of the colloidal NCs under 365 nm UV light excitation. TR-PL decay curves of (c) isopropanol treated Cs3MnBr5 NCs and as-
prepared Cs3MnBr5 NCs at 300 K. TEM image of (d) isopropanol treated Cs3MnBr5 NCs. The insets show size distribution histogram of Cs3MnBr5
NCs. (e) HRTEM image of a single Cs3MnBr5 NCs. XRD pattern of (f) isopropanol treated CsMnBr3 NCs. Wells and asterisks denote signals from
Cs3MnBr5 NCs and MnBr2 in Figure 3 f, respectively. PL spectra of (g) isopropanol treated CsMnBr3 NCs. (h) Schematic illustrations of the phase
transformation process from CsMnBr3 NCs to Cs3MnBr5 NCs. Photographs of (left) CsMnBr3 NCs and (right) isopropanol treated CsMnBr3 NCs
are shown under 254 nm and 365 nm UV light, respectively.
related to decreased nonradiative transitions due to the
improved crystalline quality.
observed (Figures 4b,d). The diffraction peaks can be indexed
as triclinic Cs2MnBr4·2H2O phase (PDF#50-0630) and some
residue of MnBr2 (Figure 4d). The crystal structure of
Cs2MnBr4·2H2O was obtained by Rietveld refinement
(Table S4 and Figure S13). The result demonstrates that
each Mn atom is coordinated with four Br atoms and two
water molecules to form an octahedron [MnBr4(H2O)2]2À, and
the octahedrons are isolated by Cs+ (Figure S14). TEM study
shows that the 0D Cs2MnBr4·2H2O NCs have an average size
of ꢀ 16.6 Æ 3.2 nm (Figure S15a). The Cs2MnBr4·2H2O NCs
show broad absorption with a tail extended to 720 nm
(Figure S16, red line), which is different from that of spin-
forbidden transition of Mn2+ in CsMnBr3 NCs. This phenom-
enon is due to the existence of sub-band gap states.[38] PL
spectra depicts that Cs2MnBr4·2H2O NCs have a blue emis-
sion peak at 440 nm with FWHM 81 nm and PLQY of 0.47%
(Figure 4e). The PL decay curves of Cs2MnBr4·2H2O NCs
(Figure S18, red line) are fitted by a double-exponential
function (t1 = 0.48 ns, t2 = 2.55 ns), which is far shorter than
To further study the phase transition process (from
CsMnBr3 to Cs3MnBr5 NCs) in isopropanol, we recorded
the XRD and PL spectra at different reaction time during the
phase transformation process. The XRD peak intensity of
CsMnBr3 NCs decreases with the increase of the peak
intensity of Cs3MnBr5 and MnBr2 (Figure 3 f and Figure S11).
PL spectra show that the green emission band is enhanced
while the red emission band is decreased (Figure 3g and
Figure S12). These results reveal that Cs3MnBr5 is a more
stable phase than CsMnBr3 in isopropanol and the CsMnBr3
phase transforms to Cs3MnBr5 phase by stripping MnBr2
(Figure 3h).
Furthermore, we found that phase transition from
CsMnBr3 to Cs2MnBr4·2H2O NCs could be triggered in
a humid environment (Figure 4a). When CsMnBr3 NCs
powders are placed in an environment with air humidity of
99% for several hours, a clear change in XRD patterns is
4
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Figure 4. (a) Illustrations of the phase transformation process of CsMnBr3 NCs and photographs of CsMnBr3 NCs, Cs2MnBr4·2H2O NCs and
Cs2MnBr4·2H2O NCs after heating at 1008C from left to right under 254 nm, 365 nm, 365 nm UV light. XRD patterns of (b) CsMnBr3 NCs,
(d) Cs2MnBr4·2H2O NCs and (f) Cs2MnBr4·2H2O NCs after heating at 1008C. Asterisks denote signals from MnBr2 in Figure 4d. (left) PLE and
(right) PL spectra of (c) CsMnBr3 NCs, (e) Cs2MnBr4·2H2O NCs and (g) Cs2MnBr4·2H2O NCs after heating at 1008C. The insets show the
colloidal NCs under 254 nm, 365 nm and 365 nm UV light excitation, respectively. (h) Schematic illustrations of the phase transformation process
of Cs3MnBr5 NCs and photographs of Cs3MnBr5 NCs, Cs2MnBr4·2H2O NCs and Cs2MnBr4·2H2O NCs after heating at 1008C from left to right
under 365 nm, 365 nm and 365 nm UV light on the glass slides.
the lifetime of CsMnBr3 NCs. It is possibly originated from
the existence of sub-band gap states and a strong electron-
phonon coupling as the presence of the O-H stretching
vibration mode in H2O molecules. The strong electron-
phonon coupling can lead to multi-phonon decay, the reduced
lifetime and low PLQY.[39,40] Similarly, water can also trigger
the phase transformation of Cs3MnBr5 NCs to
Cs2MnBr4·2H2O (PDF#50-0630) (Figure S19). In contrast
with Cs2MnBr4·2H2O NCs transformed from CsMnBr3 NCs,
the absorption spectra of Cs3MnBr5 NCs transformed
Cs2MnBr4C 2H2O NCs have the relatively shorter absorption
tail (Figure S16, green line) and higher PLQY of 1.29%,
which possibly ascribe to the reduced sub-band gap states due
to larger size. Cs2MnBr4·2H2O NCs could inversely transform
into the mixture of CsMnBr3 and Cs3MnBr5 phase during the
thermal annealing dehydration step. When Cs2MnBr4·2H2O
NCs were heated at 1008C for 1 h in ambient atmosphere,
phase structure of CsMnBr3 NCs and Cs3MnBr5 NCs were
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clearly observed in XRD patterns (Figure 4 f and Fig-
ure S19e). XRD patterns show that Cs2MnBr4·2H2O NCs
after heating at 1008C generate different amounts of
CsMnBr3 NCs and Cs3MnBr5 NCs, which result in different
emission color under UV light excitation. In addition, the PL
spectrum has dual emission band at 520 nm and 660 nm upon
excitation at 280 nm, which is consistent with the character-
istic emission peaks of CsMnBr3 NCs and Cs3MnBr5 NCs,
respectively (Figure 4g). PLE and TRPL spectra of 660 nm
and 520 nm emission band are consistent with that of
CsMnBr3 NCs and Cs3MnBr5 NCs (Figures S20–S22), respec-
tively. These results suggest a successful transformation from
blue-luminescent Cs2MnBr4·2H2O NCs to a mixed phase of
CsMnBr3 NCs and Cs3MnBr5 NCs. The mixture of CsMnBr3
and Cs3MnBr5 phase can be transformed to Cs3MnBr5
structure with isopropanol treatment, indicating that the
phase transition process is reversible (Figure S23). Further-
more, we have also listed the basic optical properties of
common lead-free perovskite NCs for comparison (Table S5).
Different from previous reported lead-free perovskite NCs
which exhibit broadband PL, the cesium manganese bromides
NCs exhibit relative narrower PL band with high color purity,
which show great potential for display applications.
Keywords: cesium manganese bromides ·
color-tunable emission · lead-free perovskite · nanocrystals
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a wide range color-tunable emission and high color purity.
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Acknowledgements
This work was supported by the National Key Research and
Development Program of China (grant 2017YFA0204800),
the National Natural Science Foundation of China (Grant
Nos. 21833009, 22088102, 21525315, 22005295), DICP
I202017, the Scientific Instrument Developing Project of the
Chinese
Academy
of
Sciences
(Grant
No.
YJKYYQ20190003), Liao Ning Revitalization Talents Pro-
gram (XLYC1802126), the Dalian City Foundation for
Science and Technology Innovation (2019J12GX031). This
work is supported by the Project funded by China Postdoc-
toral Science Foundation (2020M682159). B. Yang acknowl-
edges the funding support from the Youth Innovation
Promotion Association CAS (2021183). We would like to
thank Xiaoju Li and Haiyan Sui from Shandong University
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Conflict of Interest
The authors declare no conflict of interest.
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Manuscript received: April 20, 2021
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Revised manuscript received: May 27, 2021
Accepted manuscript online: June 20, 2021
Version of record online: && &&, &&&&
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Angewandte
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Communications
Nanocrystals
We developed a unique phase transition
strategy to engineer the emission color of
lead-free cesium manganese bromides
nanocrystals, which achieve a tunable
red/green/blue emission with high color
purity.
Q. Kong, B. Yang,* J. Chen, R. Zhang,
S. Liu, D. Zheng, H. Zhang, Q. Liu,
Y. Wang, K. Han*
&&&& — &&&&
Phase Engineering of Cesium Manganese
Bromides Nanocrystals with Color-
Tunable Emission
8
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ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 1 – 8
These are not the final page numbers!