Alkalis-doping of mixed tin-lead perovskites for efficient near-infrared light-emitting diodes

Huanqin Yu; Wenjing Chen; Zhibin Fang; Liming Ding; Bingqiang Cao; Zhengguo Xiao

doi:10.1016/j.scib.2021.07.021

Alkalis-doping of mixed tin-lead perovskites for efficient near-infrared light-emitting diodes

Sci Bull (Beijing). 2022 Jan;67(1):54-60. doi: 10.1016/j.scib.2021.07.021. Epub 2021 Jul 17.

Authors

Huanqin Yu¹, Wenjing Chen², Zhibin Fang², Liming Ding³, Bingqiang Cao⁴, Zhengguo Xiao⁵

Affiliations

¹ Hefei National Laboratory for Physical Science at the Microscale, Department of Physics, Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei 230026, China; School of Material Science and Engineering, Materials Research Center for Energy and Photoelectrochemical Conversion, University of Jinan, Jinan 250022, China.
² Hefei National Laboratory for Physical Science at the Microscale, Department of Physics, Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei 230026, China.
³ Center for Excellence in Nanoscience (CAS), Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS), National Center for Nanoscience and Technology, Beijing 100190, China. Electronic address: ding@nanoctr.cn.
⁴ School of Material Science and Engineering, Materials Research Center for Energy and Photoelectrochemical Conversion, University of Jinan, Jinan 250022, China. Electronic address: mse_caobq@ujn.edu.cn.
⁵ Hefei National Laboratory for Physical Science at the Microscale, Department of Physics, Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei 230026, China. Electronic address: zhengguo@ustc.edu.cn.

PMID: 36545960
DOI: 10.1016/j.scib.2021.07.021

Abstract

Substitution of lead (Pb) with tin (Sn) is a very important way to reduce the bandgap of metal halide perovskite for applications in solar cells, and near infrared (NIR) light-emitting diodes (LEDs), etc. However, mixed Pb/Sn perovskite becomes very disordered with high trap density when the Sn molar ratio is less than 20%. This limits the applications of mixed Pb/Sn perovskites in optoelectronic devices such as wavelength tunable NIR perovskite LEDs (PeLEDs). In this work, we demonstrate that alkali cations doping can release the microstrain and passivate the traps in mixed Pb/Sn perovskites with Sn molar ratios of less than 20%, leading to higher carrier lifetime and photoluminescence quantum yield (PLQY). The external quantum efficiency (EQE) of Sn_0.2Pb_0.8-based NIR PeLEDs is dramatically enhanced from 0.1% to a record value of 9.6% (emission wavelength: 868 nm). This work provides a way of making high quality mixed Pb/Sn optoelectronic devices with small Sn molar ratios.

Keywords: Alkali cations doping; Microstrain relaxation; Mixed Pb/Sn perovskite; NIR PeLEDs.