Nickel-bromide passivation strategy enabled highly efficient blue-emitting CsPbBr3 nanoplates for monochrome LED application

All-inorganic metal halide perovskites have attracted extensively attentions because of superior optoelectronic properties. Presently, tremendous progress is reached in green and red emitting perovskites, while the explorations of blue emitting perovskites are lag behind, and it also faces low emission efficiency and long-term stability issues. In this work, nickel-bromide passivation strategy was proposed to improve optical properties and chemical stability of blue emitting CsPbBr3 nanoplatelets (NPLs) with strong quantum-confinement effects. As a result of the repaired Br- vacancy on the surface of the NPLs and enhanced structural stability of CsPbBr3 lattice by Ni2+ doping, the emission efficiency of the NPLs is increased from 33.2% to 78%, and it can be stored up to 30 days without significant PL loss. Benefiting from the excellent overall performance, a liquid-type monochrome LED device fabricated by using the passivated CsPbBr3 NPLs as blue color convector exhibits no emission saturation even the driving current reaches as high level as 190 mA. This work paves a new way for fabricating high-quality blue emitting NPLs with extraordinary properties.