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 CsPbBr 3 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 CsPbBr 3 lattice by Ni 2+ 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 CsPbBr 3 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.