In Situ Spectroelectrochemical Investigation of Perovskite Quantum Dots for Tracking Their Transformation

Chaehyun Lee,Donghoon Han,Yeji Shin,Seog Joon Yoon,Kyoungsoo Kim

doi:10.3389/fenrg.2020.605976

Abstract

All-inorganic lead-halide perovskite quantum dots (PQDs) (CsPbX3, where X is Cl, Br, or I) have been used successfully in optoelectronic applications, such as solar cells, light-emitting diodes, photocatalysts, and lasers. These PQDs work under electrochemical bias and/or illumination with charge separation/collection by interacting with the charge-transport medium. In this study, we discuss the spectroelectrochemical characteristics of PQDs to understand the oxidation and reduction processes that occur during photoinduced charge transport or charge injection under electrochemical conditions. We also found that the PQDs underwent irreversible transformation to the precursor state of plumbate complexes under electrochemical conditions. Furthermore,in situspectroelectrochemical analysis demonstrated that hole-mediated electrochemical oxidation of PQDs resulted in their irreversible transformation. Finally, the results presented herein contribute to our understanding of the charge-transfer-mediated process in PQDs and enhance their application potential in optoelectronic devices.

Highlights

Ever since Mitzi et al described perovskites and their unique properties for optoelectronic applications in the 1990s, hybrid organic–inorganic perovskites have attracted significant attention owing to their versatile and outstanding photophysical properties (Mitzi et al, 1995; Kagan et al, 1999; Mitzi et al, 1999)
We used colloidal CsPbBr3 and CsPbI3 PQDdispersed solutions to determine the impact of electrochemical environment on their photophysical properties
All-inorganic CsPbBr3 and CsPbI3 perovskite quantum dots (PQDs) were synthesized by the hot-injection process, as described in the literature (Protesescu et al, 2015; Gualdroń -Reyes et al, 2018)

Summary

INTRODUCTION

Ever since Mitzi et al described perovskites and their unique properties for optoelectronic applications in the 1990s, hybrid organic–inorganic perovskites have attracted significant attention owing to their versatile and outstanding photophysical properties (Mitzi et al, 1995; Kagan et al, 1999; Mitzi et al, 1999). Perovskites exhibit a unique photoelectrochemical behavior depending on the applied bias or illumination They exhibit several intriguing phenomena, such as current density–voltage (J–V) hysteresis (Chen et al, 2015a), phase segregation in mixed halide perovskites (Hoke et al, 2015; Yoon et al, 2016a), charge/ion accumulation at interfaces (Zolfaghari et al, 2018), charge-recombination mechanisms that are dependent on illumination conditions (Draguta et al, 2016), and selective electron/hole-mediated redox processes (Samu et al, 2019). The spectroelectrochemical analysis approach presented lays the foundation for engineering optoelectronic devices, such as PQD-based solar cells, photocatalysts, and water-splitting groups

MATERIALS AND METHODS

RESULTS AND DISCUSSION

DATA AVAILABILITY STATEMENT