Efficient electronic coupling and heterogeneous charge transport of zero-dimensional Cs4PbBr6 perovskite emitters

Abstract

Organic and/or inorganic halide perovskites have become a new class of optoelectronic materials by virtue of excellent attractive physical and chemical characteristics. In this context, the zero-dimensional (0-D) cesium lead bromide (Cs₄PbBr₆) perovskite with outstanding photoluminescence (PL) properties has been recognized as the most promising candidate. However, the electron transfer dynamics and electrochemical behaviors of Cs₄PbBr₆ emitters still remain unclear. Herein, we prepared the 0-D Cs₄PbBr₆ perovskite emitters and investigated the exciton transport and electrochemical dynamics by utilizing temperature-dependent transient photoluminescence (TRPL) and electrogenerated chemiluminescence (ECL) techniques, respectively. Stronger electronic coupling of Cs₄PbBr₆ emitters arises from the overlap of electronic wavefunctions, indicating the increased possibility for the generation of electrochemiluminescence. Through the determination of the diffusion coefficient and electron-transfer rate by using an electrochemical method, we confirm that effective heterogeneous charge transfer at the interface of the electrode and electrolyte results in red-shifted ECL emission in the presence of benzoyl peroxide (BPO) as the co-reactant. The development of zero-dimensional perovskite emitters opens up a new avenue in the field of emerging optoelectronic and biosensing technologies, including but not limited to ECL devices, ECL immunoassays, organic light-emitting diodes, light-emitting electrochemical cells, and other bio-related detections.