High Efficient Cesium Copper Halide-Based Light Emitting Diodes with an insulating layer

Cesium copper halides-based materials have attracted wide attention due to their high photoluminescence quantum yield (PLQY), low toxicity, and outstanding stability. For obtaining high efficiency cesium copper halides-based light emitting diode (LED), two factors are of vital significance, i.e., reduced interfacial quenching and balanced charge injection. Here we develop a simple method of inserting an insulating layer between the cesium copper halides and the hole injection layer (HIL) to reduce the exciton quenching by the HIL and achieve more balanced charge injection into the emitting layer. Benefiting from this approach, the highest EQE of the cesium copper halides-based LEDs is improved from 2.29% to 4.29%.