Boosting photodetection performance of Cs2AgBiBr6 through A-site Rb substitution and interfacial engineering

Guobiao Cen; Haigang Sheng; Zhengxuan Wang; Ling Yi; Hengchao Sun; Yipeng An; Chuanxi Zhao; Wenjie Mai

doi:10.1016/j.jcis.2023.07.194

Boosting photodetection performance of Cs₂AgBiBr₆ through A-site Rb substitution and interfacial engineering

J Colloid Interface Sci. 2023 Dec 15;652(Pt A):34-40. doi: 10.1016/j.jcis.2023.07.194. Epub 2023 Aug 4.

Authors

Guobiao Cen¹, Haigang Sheng¹, Zhengxuan Wang², Ling Yi³, Hengchao Sun³, Yipeng An⁴, Chuanxi Zhao⁵, Wenjie Mai⁶

Affiliations

¹ Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong 510632, China.
² School of Physics & International United Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China.
³ Beijing Smart-Chip Microelectronics Technology Co., Ltd., Beijing 100192, China.
⁴ School of Physics & International United Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China. Electronic address: ypan@htu.edu.cn.
⁵ Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong 510632, China; Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Jinan University, Guangzhou, Guangdong 511443, China. Electronic address: tcxzhao@email.jnu.edu.cn.
⁶ Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong 510632, China; Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Jinan University, Guangzhou, Guangdong 511443, China.

PMID: 37591081
DOI: 10.1016/j.jcis.2023.07.194

Abstract

Bismuth-based double perovskite Cs₂AgBiBr₆ shows promise as a photodetection material. However, its detection performance and application are limited by high-exciton binding energy and poor carrier mobility. In this study, we address these limitations by delicately designing a solution-based method for incorporating A-site Rubidium (Rb) substitution into Cs₂AgBiBr₆ double perovskite films. The introduction of Rb resulted in a significant decrease in trap defect density and an improvement in film quality. The trap-filled limit voltage (V_TFL) of pure and Rb-doped CABB film is determined to be 1.71 V and 0.48 V, respectively. Subsequently, by introducing an ultrathin atomic-layer-deposited (ALD) TiO₂ films, the fabricated CABB photodetectors exhibit significantly improved photoresponse performance. The response speed and -3dB bandwidth are boosted from ∼93 ms to ∼350 μs and broadened from 1.4 kHz to 17 kHz, respectively. Density Functional Theory (DFT) calculations indicate Rb-substitution shortens the bond length and weaken exciton binding energy. Furthermore, we demonstrate a wireless near ultraviolet (UV) light communication system using CABB photodetectors as light receivers. Our findings provide an efficient approach to utilize A-site cation substitution as a tuning parameter for photodetection in high-exciton binding energy perovskite materials, thereby extending the potential applications of other functional perovskites.

Keywords: A-site substitution; Exciton binding energy; Light communication.