Hole-Injection\nLayer-Free Perovskite Light-Emitting\nDiodes

Abstract

In this study, a\ndual-source vapor evaporation method was employed\nto fabricate the high-quality CsPbBr₃ thin films with a\ngood crystalline and high surface coverage. Temperature-dependent\nand excitation power-dependent photoluminescence measurements were\nperformed to study the optical properties of the CsPbBr₃ material. Further, based on the experimental data, the temperature\nsensitivity coefficient of band gap and exciton binding energy were\nestimated. More importantly, for the first time, we designed and prepared\na hole-injection layer-free perovskite light-emitting diode (LED)\nbased on the Au/MgO/CsPbBr₃/n-MgZnO/n⁺-GaN structure,\nproducing an intense green emission (∼538 nm) with a high purity.\nBesides, the device demonstrated a high luminance of 5025 cd/m², an external quantum efficiency of 1.46%, a current efficiency\nof 1.92 cd/A, and a power efficiency of 1.76 lm/W. We studied in detail\nthe current–voltage and electroluminescence properties of the\nprepared device and proposed the hole generation models and the carrier\ntransport/recombination mechanisms to make these interesting characteristics\ncertain. The results obtained would provide a new and effective strategy\nfor the design and preparation of perovskite LEDs.