H2O treatment-induced uniform NiOX interfacial layer boosting brightness and light-emitting efficiency of blue perovskite electroluminescence

The reported NiOx interfacial layers in blue perovskite light-emitting diodes (PeLEDs) usually require high-temperature annealing and complex interface modification. Herein, we report a kind of uniform NiOx anode interfacial layer induced by H2O treatment, which effectively enhances the brightness and light-emitting efficiency of blue PeLEDs simultaneously. Compared to the as-prepared NiOx anode interfacial layer, H2O treatment renders uniform and pinhole-free NiOx morphology. The solution-processed perovskite blue emissive layer prepared atop the H2O-treated NiOx interfacial layer demonstrates enhanced photoluminescent property and superior morphology with low trap density. The blue PeLEDs employing H2O-treated NiOx as anode interfacial layer show a maximum luminance of 9052 cd/m2 and a maximum external quantum efficiency (EQE) of 1.80%, whereas the control device based on the as-prepared NiOx anode interfacial layer merely exhibits a maximum luminance of 3850 cd/m2 and an EQE of 0.88%, leading to about 135% and 104% increase in brightness and efficiency, respectively. The PeLEDs emit pure blue light with emission peak located at 482 nm and demonstrate superior spectral stability under different driving voltages and operating time.