Efficient All-Inorganic Perovskite Light-Emitting\nDiodes with Cesium Tungsten Bronze as a Hole-Transporting Layer

Abstract

The realization of\nhigh-performance optoelectronic devices requires\nexcellent charge-transporting layers and efficient carrier recombination.\nHerein, we synthesized cesium tungsten bronze (Cs_0.32WO₃) nanocrystals and utilized them as the hole-transporting\nmaterial to fabricate all-inorganic perovskite light-emitting diodes\n(PeLEDs). Due to the excellent carrier balance characteristics via\ncomparison between the hole-only device and electron-only device,\nthe all-inorganic PeLEDs with CsPbBr₃ as the light-emitting\nlayer present the maximum current efficiency of 31.51 cd/A and external\nquantum efficiency (EQE) of 8.48%, which are self-evidently enhanced\ncompared with the PEDOT:PSS (14.78 cd/A, 4.03%) and WO₃ (24.75 cd/A, 6.18%) based devices. Considering the remarkably improved\ndevice performance, the proposed HTL of Cs_0.32WO₃ is promising, acting as a favorable building block for high-efficiency\nlight-emitting devices.