Electronic Supporting Information

for

One-Pot Scalable Synthesis of All-Inorganic

Perovskite Nanocrystals with Tunable Morphology,

Composition and Photoluminescence

Emmanuel Acheampong Tsiwah†a, Yanxi Ding†a, Zixiong Lia, Zhiyong Zhaoa, Mingqing Wangb*,

Chao Hua, Xiaoqing Liuc, Chenghua Sund, Xiujian Zhaoa, Yi Xie*a

a State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology

(WUT), No. 122, Luoshi Road, Wuhan 430070, P. R. China

b UCL Institute for Materials Discovery, University College of London, Room 107, Roberts

Building, Malet Place, London WC1E 7JE, United Kingdom

c Center of Materials Research & Testing, Wuhan University of Technology, Wuhan, Hubei

430070, P.R. China

d Department of Chemistry and Biotechnology, Faculty of Science, Engineering & Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia.

†These authors contributed equally to this work.

Email:xiey@whut.edu.cn

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Electronic Supplementary Material (ESI) for CrystEngComm.This journal is © The Royal Society of Chemistry 2017

Contents

1. Optical spectra and TEM images of Cs-Pb-Br and Cs-Pb-Cl NCs synthesized in the presence

of OM or OTA alone .......................................................................................................................3

2. Characterization of Cs-Pb-Br NCs collected at different temperatures in the presence of OA

and OM ............................................................................................................................................4

3. Characterization of Cs-Pb-Br NCs collected at different time in the presence of OA and OM..8

4. Characterization of Cs-Pb-Br NCs collected with different amounts of OM............................10

5. Characterization of Cs-Pb-Br nanosheets achieved in the presence of OA and OTA...............11

6. Characterization of Cs-Pb-Cl NCs synthesized in the presence of OA and OM.......................14

7. Characterization of Cs-Pb-Cl NCs synthesized in the presence of OA and OTA.....................16

8. Characterization of Cs-Pb-I NCs achieved in the presence of OA and OM .............................18

9. Morphological evolution of the as-synthesized NCs upon E-beam irradiation.........................20

10. Characterization of halide-mixed NCs achieved by tuning the precursor halide ratios .........21

11. Large-scale synthesis of perovskite CsPbBr3 NCs. ................................................................23

References......................................................................................................................................24

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1. Optical spectra and TEM images of Cs-Pb-Br and Cs-Pb-Cl NCs synthesized in the presence

of OM or OTA alone

Figure S1. Optical absorption (a), PL emission spectra (b) and TEM images (c-e) of Cs-Pb-Br and

Cs-Pb-Cl NCs synthesized in the presence of OM or OTA alone as dictated.

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2. Characterization of Cs-Pb-Br NCs collected at different temperatures in the presence of OA

and OM

To analyze the morphological, structural and optical evolution of Cs-Pb-Br NCs, we collected

TEM images, optical absorption, PL, XRD patterns and size distribution histogram of the

intermediates at different reaction stages. The representative results are reported in Figures

S2-5 and Table S1. At the early stage (e.g. temperature at 90-100 oC), the reaction is dominated

by the generation of nanocubes with average edge length of 5.3-6.0 nm (Figure S2a-b, Table S1).

XRD patterns indicate the coexistence of orthorhombic perovskite CsPbBr3 phase (JCPDS No.

98-009-7851) along with non-perovskite rhombohedral Cs4PbBr6 (JCPDS No. 01-073-2478)

phase in these nanocubes (Figure S2c). Increasing reaction temperature (e.g. over 110 oC) leads

to the formation nanoplates (Figure S2c-e), which are verified to be orthorhombic perovskite

CsPbBr3 (JCPDS No. 98-009-7851, Figure S3c). The HRTEM analyses (Figure S5) are in agreement

with the XRD patterns. The narrow size distributions of the edge length in the nanocubes and

thickness in the nanoplates are shown in Figure S4. Overall the PL band, which is due to

excitonic recombination, is red-shifted from 492.0 to 525.0 nm by increasing reaction

temperature (Figure S3b, Table S1).

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Figure S2. TEM images of Cs-Pb-Br aliquots collected at 90 oC (a), 100 oC (b), 110 oC (c), 120 oC

(d), 165 oC (e), 180 oC (f), respectively, during heating the mixture of precursors (i.e. Cs2CO3,

PbBr2) in OM, OA and ODE.

Figure S3. Optical absorption spectra (a), PL emission spectra (b) and XRD patterns of Cs-Pb-Br

aliquots collected at different temperatures as dictated.

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Figure S4. Size distribution of Cs-Pb-Br nanocubes (cube edge length) collected at 90 oC (a) and

100 oC (b), and perovskite CsPbBr3 nanoplates (in thickness) collected at 110 oC (c), respectively.

Figure S5. HRTEM images of single Cs-Pb-Br NCs collected at 90 oC (a), 100 oC (b), 110 oC (c) and

120 oC (d), respectively. Each scale bar presents 5 nm. The lattice spacing of 0.396 nm in panels

a-b) corresponds to the (300) plane of rhombohedral Cs4PbBr6 phase. The characteristic lattice

spacing of 0.412 and 0.290 nm in panel c-d) can be respectively assigned to the (200) and (202)

planes of orthorhombic CsPbBr3 structure.

Table S1. Summary on the size and optical properties of the Cs-Pb-Br NCs collected at different

temperatures.

Sample Temperature

(oC)

Average

sizea (nm)

Excitonic

peak (nm)

PL peak

(nm)

FWHMb

(nm)

Sample1 90 5.3 482.8 492.0 26.0

Sample2 100 6.0 502.0 506.0 24.8

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Sample3 110 6.5 501.4 510.0 23.8

Sample4 120 7.0 501.1 512.9 21.7

Sample5 165 - 500.8 525.0 18.2

a average cube edge length of nanocubes or average thickness of nanoplates

b full width at half-maximum

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3. Characterization of Cs-Pb-Br NCs collected at different time in the presence of OA and OM

Figure S6 presents the evolution of morphology, phase and optical spectra of the Cs-Pb-Br NCs

collected at different reaction time. The emission peaks redshift with increasing time, most

probably due to the increment of particle size. Based on the previous analysis on the XRD

patterns of samples at different temperatures, we attribute the phases of nanocubes formed

within 30 min to mixed orthorhombic CsPbBr3 (JCPDS No. 98-009-7851) and rhombohedral

Cs4PbBr6 (JCPDS No. 01-073-2478). With the prolonging reaction time, the experimental XRD

patterns of the NPLs collected at 60 and 120 min match well with the orthorhombic crystal

structure of CsPbBr3 (Figure S6e).

Figure S6. (a-d) Representative TEM images of Cs-Pb-Br nanocubes (a-b) and nanoplates (c-d)

collected at 0 min and 30 min (for nanocubes), 60 min and 120 min (for nanoplates),

respectively, via a one-pot reaction at 95 oC. (e-g) XRD patterns (e), optical absorption (f) and PL

spectra (g) of the Cs-Pb-Br NCs achieved at different reaction time as dictated.

Table S2. Summary on the size and optical properties of the Cs-Pb-Br NCs collected at different

reaction time at 95 oC.

Sample Reaction

time (min)

Average

sizea (nm)

Excitonic

peak (nm)

PL peak

(nm)

FWHMb

(nm)

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Sample1 0 5.7 498.8 504.9 24.4

Sample2 30 7.0 505.3 513.9 21.9

Sample3 60 7.3 507.8 516.0 19.9

a average cube edge length of nanocubes or average thickness of nanoplates

b full width at half-maximum

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4. Characterization of Cs-Pb-Br NCs collected with different amounts of OM

Figure S7. (a-c) Representative TEM images of perovskite CsPbBr3 NCs collected with OM

amounts of 1.0 mL (a), 2.0 mL (b) and 4.0 mL (c), respectively, by fixing the amount of OA as 0.5

mL. Each scale bar represents 50 nm. (d-f) XRD patterns (d), optical absorption spectra (e) and

PL emission spectra (f) of the corresponding samples achieved with different amounts of OM as

dictated.

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5. Characterization of Cs-Pb-Br nanosheets achieved in the presence of OA and OTA

The synthesis of perovskite CsPbBr3 nanosheets was performed under the same conditions as

that of previously-discussed CsPbBr3 nanoplates, except that ligand OM was replaced by OTA.

We collected aliquots at different reaction temperatures and time, and presented their TEM

images, XRD patterns and optical spectra (Figures S8-10). At the early stage (e.g. temperature

below 120 oC), the reaction is dominated by the generation of irregular shapes of NCs with

average size around 30-40 nm (Figure S8a). Prolonging reaction leads to the formation of

rectangle-shaped nanosheets with edge length of micrometers (Figures S8b-c). With further

increasing temperature or reaction time, the nanosheets are partially etched and become

irregular in shape, along with the formation of holes within the nanosheets (Figures S8d-e and

S10c-d). By analogy with the synthesis of Cs-Pb-Br in the presence of OA and OM, early stage

reaction leads to the formation of mixed phases of perovskite CsPbBr3 (orthorhombic, JCPDS

No. 98-009-7851) and non-perovskite Cs4PbBr6 (rhombohedral, JCPDS No. 01-073-2478, Figure

S8h, black curve). Increasing reaction temperature (e.g. above 130 oC) allows for the formation

of pure perovskite CsPbBr3 NCs (Figure S8h). The phase attribution can be further confirmed by

HRTEM images (Figure S9). Overall the PL emission bands are red-shifted from 513 to 525 nm

either by increasing reaction temperature or by prolonging time (Figures S8g and S10f).

Figure S8. (a-e) TEM images of Cs-Pb-Br aliquots collected at 120 oC (a), 130 oC (b), 140 oC (c),

150 oC (d) and 160 oC (e), respectively, via one-pot reaction in the presence of both OTA and OA.

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(f-h) Optical absorption (f), PL spectra (g) and XRD patterns of the Cs-Pb-Br aliquots collected at

different temperatures as dictated.

Figure S9. HRTEM images of the typical Cs-Pb-Br nanosheet collected at 130 oC (a) and 140 oC

(b), respectively, via one-pot reaction in the presence of both OTA and OA. The lattice spacing of

0.291 nm in the typical nanosheets correspond to the (202) plane of orthorhombic perovskite

CsPbBr3 (JCPDS No. 98-009-7851).

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Figure 10. (a-d) Representative TEM images of Cs-Pb-Br NCs collected at 5 min (a), 30 min (b),

and 120 min (c-d), respectively, via a one-pot reaction at 110 oC in the presence of both OA and

OM. Panel d) shows the magnified image of the domain marked by red in panel c). (e-f) Optical

absorption spectra (e) and PL emission bands (f) of the Cs-Pb-Br NCs achieved at different

reaction time as dictated.

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6. Characterization of Cs-Pb-Cl NCs synthesized in the presence of OA and OM

Figure S11. (a-e) Representative top-view TEM images of Cs-Pb-Cl NCs collected at 0 min (a), 10

min (b), 30 min (c), 60 min (d) and 120 min (e), respectively, via a one-pot synthesis at 95 oC in

the presence of OA and OM. (f) Representative side-view TEM images of Cs-Pb-Cl NCs collected

at 30 min. Each scale bar represents 50 nm. The OA and OM are 0.5 mL and 1.0 mL, respectively,

in each synthesis.

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Figure S12. XRD patterns (a), optical absorption (b), and PL emission spectra (c) of the Cs-Pb-Cl

NCs collected at different reaction time as dictated, via one-pot synthesis reaction at 95 oC. The

OA and OM are 0.5 mL and 1.0 mL, respectively, in each synthesis.

Figure S13. (a-c) Representative TEM images of Cs-Pb-Cl NCs collected in the presence of 1 mL

(a), 2 mL (b) and 4 mL (c) of OM, respectively, via a one-pot synthesis at 95 oC. Each scale bar

represents 50 nm. The OA is 0.5 mL in all syntheses. (d-e) Optical absorption (d) and PL spectra

(e) of the Cs-Pb-Cl NCs collected in the presence of different amounts of OM as dictated.

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7. Characterization of Cs-Pb-Cl NCs synthesized in the presence of OA and OTA

Figure S14. (a-f) TEM images of Cs-Pb-Cl NCs collected at 110 oC (a), 120 oC (b), 130 oC (c), 140

oC (d) , 150 oC (e) and 160 oC (f), respectively, in the presence of both OTA and OA.

Figure S15. XRD patterns (a), optical absorbance (b) and PL spectra (c) of Cs-Pb-Cl NCs collected

at different reaction temperatures as dictated, via one-pot reaction in the presence of OTA and

OA.

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Figure S16. Side-view TEM image of typical Cs-Pb-Cl nanoplates as-formed at 130 oC (a), and

HRTEM images of Cs-Pb-Cl nanoplate collected at 130 oC (b) and 140 oC (c), respectively, via one-

pot reaction in the presence of OTA and OA. The lattice spacing of 0.280 nm and 0.396 nm in the

typical NPLs correspond to the (002) and (011) planes of cubic perovskite CsPbCl3 (JCPDS No. 98-

020-1250).

Figure S17. (a-c) Representative TEM images of Cs-Pb-Cl NCs collected at 5 min (a), 30 min (b),

and 120 min (c), respectively, via a one-pot synthesis at 110 oC. (d-f) XRD patterns (d), optical

absorbance (e) and PL spectra (f) of various Cs-Pb-Cl NCs collected at different time as dictated.

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8. Characterization of Cs-Pb-I NCs achieved in the presence of OA and OM

The synthesis of Cs-Pb-I samples was performed under the same conditions as that of CsPbBr3

NPLs, by replacing precursor PbI2 with PbBr2. The representative TEM images, XRD patterns and

optical spectra are reported in Figures S18-20. It is noteworthy that the capping ligands,

reaction temperature and time are critical in case of Cs-Pb-I synthesis. No any Cs-Pb-I NCs can

be achieved in the absence of OM. In the presence of both OM and OA, NCs in sphere-like and

parallelogram-like shapes are synthesized at 0 min of 95 oC (Figure S18a). As the reaction

proceeds, small NCs together bigger rod-like particles, can be collected within 20 min (Figure

S18a-c). The dispersions of these samples display red emission (Figure S19c). Increasing

reaction time (e.g. over 20 min) leads to the formation of pure large rod-like particles (Figure

S18d-f) without PL emission. These rod-like particles are confirmed by both XRD and HRTEM

analyses to be mainly perovskite orthorhombic CsPbI3 (JCPDS No. 00-018-0376, Figure S19a and

S20c).

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Figure S18. Evolution of the morphology of the as-prepared CsPbI3 nanostructure collected at 0

min (a), 5 min (b), 20 min (c), 40 min (d), 60 min (e) and 120 min (f), respectively, at 95 oC in the

presence of OA and OM.

Figure S19. Evolution of the XRD patterns (a) optical spectra (b) and PL spectra (c) of the as-

prepared CsPbI3 NCs collected at different reaction time as dictated, at 95 oC in the presence of

OA and OM. Inset in panel c) provides the photograph of as-obtained NC dispersion under UV

illumination.

Figure S20. TEM (a-b) and HRTEM images (c) of the representative rod-like CsPbI3 NCs.

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9. Morphological evolution of the as-synthesized NCs upon E-beam irradiation

Figure S21. Evolution of TEM images of the CsPbCl3 perovskite NCs over different E-beam

irradiation time during TEM measurement at a working voltage of 200 kV. The irradiation time

increases from panel a) to panel d).

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10. Characterization of halide-mixed NCs achieved by tuning the precursor halide ratios

Figure S22. (a-f) TEM images of Cs-Pb-Cl NCs (a) and Cs-Pb-Br NCs (f) and Cl-Br-mixed NCs

collected with precursor Cl:Br ratios of 4:1 (b), 2:1 (c), 1:1 (d) and 1:4 (e). (g-h) Optical

absorption (g), PL emission spectra (h) of the above samples. The reaction temperature is 95 oC.

Inset in panel h) reports the optical photograph of the corresponding NC solution under UV

irradiation.

Figure S23. (a-f) TEM images of Cs-Pb-Br NCs (a) and Cs-Pb-I NCs (f) and I-Br-mixed NCs

collected with precursor Br:I ratios of 2:1 (b), 1:1 (c), 1:2 (d) and 1:4 (e). (g-h) Optical absorption

(g), PL emission spectra (h) of the above samples. The reaction temperature is 95 oC. Inset in

panel h) reports the optical photograph of the corresponding NC solution under UV irradiation.

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Table S3. Summary on the size and optical properties of the NCs collected with different

precursor Cl:Br ratios.

Precursor Cl:Br ratio Excitonic peak (nm) PL peak (nm) FWHM(nm)

1:0 408.2 417.0 10.6

4:1 417.2 429.0 13.3

2:1 423.5 439.9 15.3

1:1 435.5 453.0 15.7

1:2 442.5 470.0 23.2

0:1 505.1 513.9 21.5

Table S4. Summary on the size and optical properties of the NCs collected with different

precursor Br:I ratios.

Precursor Br:I ratio Excitonic peak (nm) PL peak (nm) FWHM (nm)

1:0 503.5 513.9 23.3

2:1 501.0 520.9 28.2

1:1 501.2 544.0 45.7

1:2 492.6 586.0 45.7

1:4 551.3 623.0 45.8

0:1 695.539 688.0 39.8

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11. Large-scale synthesis of perovskite CsPbBr3 NCs

Figure S24. (a-b) Photographs of as-obtained large-scale CsPbBr3 dispersion under normal

indoor light (a) and UV illumination (b). (c) weighing measurement of the dried NPs. (d) TEM

image (d), HRTEM image (e), optical absorption (red line) and PL spectrum (black line) (f), TGA

analysis (g), and time-resolved PL (t=7.76 ns) of the large-scale CsPbBr3 NCs (h). Inset in panel f)

provides the photographs of the CsPbBr3 NC dispersion under UV irradiation.

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References

1. Akkerman, Q. A.; D’Innocenzo, V.; Accornero, S.; 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 (32), 10276-10281.

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