Electrogenerated Chemiluminescence of Perovskite Quantum Dots

Abstract

Metal halide perovskites have attracted immense scientific interest owing to their unique optoelectronic properties, such as high absorption coefficient, band gap tunable in the entire visible range, and high photoluminescence quantum efficiency. Perovskites have been applied to applications in solar cells, photodetectors, nanolasers, and light emitting diodes (LED) because of these unique properties. Light emitting diodes are based on the luminescence of the material. Tunable photoluminescence (PL) and electrogenerated chemiluminescence (ECL) can be obtained from perovskite quantum dots (QDs) by varying their size and shapes because of quantum confinement effect. In this study, ligand assisted precipitation method is used to synthesize lead based mixed chloride and bromide perovskite quantum dots. The absorbance, fluorescence at 450nm, lifetime and quantum yield results will be presented. The average diameter of 3.5±1nm and the d-spacing of 0.3nm was determined using HR-TEM. ECL can be obtained from a transparent electrode coated with perovskite QDs using tripropylamine (TPrA) as the co-reactant in acetonitrile as solvent, although the ECL performance of dry-coated perovskite QDs suffers from decomposition and/or dissolution of the dots into electrolyte. The ECL stability issue can be partially addressed by coating the QDs along with polystyrene film accompanied with decrease in ECL intensity due to the sluggish charge transfer through polystyrene film. A dual ECL peak spectrum with emissions at 480 nm and 580 nm is observed over the period of ECL generation and collection. Further experiments need to be done to fully understand the mechanism behind this shift.