Halide-Rich Synthesized Cesium Lead Bromide Perovskite Nanocrystals for Light-Emitting Diodes with Improved Performance

Transcription

1 Supporting Information Halide-Rich Synthesized Cesium Lead Bromide Perovskite Nanocrystals for Light-Emitting Diodes with Improved Performance Peizhao Liu,, #, Wei Chen,, #, Weigao Wang, Bing Xu, Dan Wu, Junjie Hao, Wanyu Cao, Fan Fang, Yang Li, Yuanyuan Zeng, Ruikun Pan, Shuming Chen, Wanqiang Cao*, Xiao Wei Sun* and Kai Wang* School of Materials Science and Engineering, Hubei University, Wuhan , China Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen , China Lehrstuhl für Funktionelle Materialien, Physik-Department, Technische Universität München, Garching, Germany School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore , Singapore # These two authors contributed to this work equally. Corresponding authors: Wanqiang Cao: caowanq@163.com Xiao Wei Sun: sunxw@sustc.edu.cn Kai Wang: wangk@sustc.edu.cn

2 Figure S1. TEM and HRTEM images of CsPbBr 0.9 Cl 2.1 for blue emission, CsPbBr 3 for green emission and CsPbBr 0.9 I 2.1 for red emission.

3 Figure S2. The size distribution of the NCs according to the TEM images in Figure S1.

4 Figure S3. The normalized PL spectra of all the NCs.

5 Table S1. The detailed information of time-resolved PL decay of all purified CsPbBr 3 NCs. Sample (precursors) τ aver (ns) τ 1 (ns) τ 2 (ns) τ 3 (ns) A 1 /P1(%) A 2 /P2(%) A 3 /P3(%) Sample 1 (PbBr 2 ), reference Sample 2 (PbO+2NH 4 Br) Sample 3 (PbO+3NH 4 Br) Sample 4 (PbO+4NH 4 Br) / / / / / / / / / / / /3 Time-resolved PL decay curves were fitted to a tri-exponential decay curves of A(t)=A 1 exp(-t/τ 1 )+A 2 exp(-t/τ 2 )+A 3 exp(-t/τ 3 ) (1) The average lifetimes were calculated using τ aver =( A 1 *τ 1^2+A 2 *τ 2^2+A 3 *τ 3^2)/( A 1 *τ 1 +A 2 *τ 2 +A 3 *τ 3 ) (2) And the percentages were calculated by P x =A x *τ x /( A 1 *τ 1 +A 2 *τ 2 +A 3 *τ 3 ) (3)

6 Figure S4. Chemical states of CsPbBr 3 perovskite NCs synthesized with different ratio of raw materials. (a) Br/Pb ratio. High-resolution XPS analyses corresponding to (b) Cs 3d, (c) Pb 4f, and (d) Br 3d.

7 Figure S5. DS 1 performances. (a) Current density (CE) and luminance (L) versus driving voltage characteristics. (b) EL spectra at an applied voltage of 9.5 V. (c) Current efficiency (CE) and external quantum efficiency (EQE) as a function of luminance. (d) Power efficiency (PE) as a function of the luminance.

8 Figure S6. DS 2 performances. (a) Current density (CE) and luminance (L) versus driving voltage characteristics. (b) EL spectra at an applied voltage of 9.5 V. (c) Current efficiency (CE) and external quantum efficiency (EQE) as a function of luminance. (d) Power efficiency (PE) as a function of the luminance.

9 Figure S7. DS 3 performances. (a) Current density (CE) and luminance (L) versus driving voltage characteristics. (b) EL spectra at an applied voltage of 9.5 V. (c) Current efficiency (CE) and external quantum efficiency (EQE) as a function of luminance. (d) Power efficiency (PE) as a function of the luminance.

10 Figure S8. DS 4 performances. (a) Current density (CE) and luminance (L) versus driving voltage characteristics. (b) EL spectra at an applied voltage of 9.5 V. (c) Current efficiency (CE) and external quantum efficiency (EQE) as a function of luminance. (d) Power efficiency (PE) as a function of the luminance.

11 Figure S9. The comparison of the performances of different LED devices, DS 1-4, with Br-rich NCs. All the data are normalized by DS 1 LED device with normal NCs.

12 Table S2. Comparisons of representative green CsPbBr 3 perovskite NC LEDs.

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