Modulating the optical and electrical properties of MAPbBr3 single crystals via voltage regulation engineering and application in memristors

Jun Xing,Yuting Zou,Zhi Yu,Wenchi Kong,Ding Zhou,Chen Zhao,Chunlei Guo,Weili Yu,Yuwei Shan,Qingfeng Dong

doi:10.1038/s41377-020-00349-w

Abstract

Defect density is one of the most significant characteristics of perovskite single crystals (PSCs) that determines their optical and electrical properties, but few strategies are available to tune this property. Here, we demonstrate that voltage regulation is an efficient method to tune defect density, as well as the optical and electrical properties of PSCs. A three-step carrier transport model of MAPbBr3 PSCs is proposed to explore the defect regulation mechanism and carrier transport dynamics via an applied bias. Dynamic and steady-state photoluminescence measurements subsequently show that the surface defect density, average carrier lifetime, and photoluminescence intensity can be efficiently tuned by the applied bias. In particular, when the regulation voltage is 20 V (electrical poling intensity is 0.167 V μm−1), the surface defect density of MAPbBr3 PSCs is reduced by 24.27%, the carrier lifetime is prolonged by 32.04%, and the PL intensity is increased by 112.96%. Furthermore, a voltage-regulated MAPbBr3 PSC memristor device shows an adjustable multiresistance, weak ion migration effect and greatly enhanced device stability. Voltage regulation is a promising engineering technique for developing advanced perovskite optoelectronic devices.

Highlights

Perovskite materials have been used in a variety of optoelectronic devices, such as solar cells[1,2,3], photodetectors[4,5], field effect transistors[6,7,8], lasers[9,10], and light emitting diodes[11,12], due to their excellent intrinsic properties[13,14,15]
Aside from being convenient and easy to control, voltage regulation can be dynamically tracked by steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements in situ[29], which provides specific insight into how the defect density in the MAPbBr3 single-crystal bulk (MPB SCBK) evolves
The best voltage for regulation is achieved at 20 V, wherein the average carrier lifetime is increased by 32.04%, the surface defect density is reduced by 24.27% and the PL intensity is increased by 112.96% compared with the values obtained with no bias

Summary

Introduction

Perovskite materials have been used in a variety of optoelectronic devices, such as solar cells[1,2,3], photodetectors[4,5], field effect transistors[6,7,8], lasers[9,10], and light emitting diodes[11,12], due to their excellent intrinsic properties[13,14,15]. Despite the possibility of engineering perovskites, there are still bottlenecks in the advancement of perovskite applications, in the case of perovskite single crystals (PSCs), which have been reported by Shi[14] and Dong[15] to have an ultralow trap density and a large carrier lifetime. For applications such as solar cells, lasers, LEDs or transistors, how the fundamental parameters can be tuned to maximize the device efficiency is still unclear, it is critical. Aside from being convenient and easy to control, voltage regulation can be dynamically tracked by steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements in situ[29], which provides specific insight into how the defect density in the MAPbBr3 single-crystal bulk (MPB SCBK) evolves

Methods

Results

Conclusion