High-Efficiency Red Light-Emitting Diodes Based on Multiple Quantum Wells of Phenylbutylammonium-Cesium Lead Iodide Perovskites

Inorganic–organic hybrid perovskites have drawn considerable attention in photovoltaics and light-emitting diodes (LEDs) due to their exceptional optoelectronic properties. Perovskite multiple quantum wells (MQWs), which employ large organic ammonium cations to form layered structures, have been developed for high-efficiency perovksite LEDs (PeLEDs). However, little is known about the impacts of large organic ammonium cations on the properties of MQW films. In this work, we report MQW perovskites of phenylbutylammonium-cesium lead iodides, which exhibit a photoluminescence peak at 664 nm with a quantum efficiency of 58%. These perovskite MQW films enable red LEDs with high external quantum efficiencies (EQEs) of up to 13.3%. Furthermore, we deposit MQW perovskites of butylammonium-cesium lead iodides. The comparisons of the two perovskite MQW films demonstrate that the choices of large organic ammonium cations significantly influence the properties of the perovskite MQW films, that is, distributions of the quantum-well thicknesses, energy transfer processes, and recombination channels of the emissive centers. Our study shall shed light on the rational design of high-performance perovskite MQW films toward their potential application as red light sources.