Novel Composite of Nickel Thiocyanate-Based All-Inorganic Lead Bromide Perovskite Nanocrystals with Enhanced Luminescent and Stability for White Light-Emitting Diodes

Doping of CsPbBr3 perovskite nanocrystals (PNCs) to achieve excellent material properties is accelerating due to their increasing use in optoelectronic devices. Herein, a novel composite of CsPbBr3 PNCs with nickel thiocyanate Ni(SCN)(2) is reported, exhibiting stronger photoluminescence (PL) and more extended stability. The addition of Ni(SCN)(2) at different molar concentrations reduces the surface trap states of the host PNCs. Therefore, the microstrain, dislocation density, PL emission linewidth, and Urbach energy decrease, resulting in an increased photoluminescence quantum yield (PLQY) from 72% to high above 90%. When stored in the ambient atmosphere for 120 days, the PLQY of doped PNCs is maintained by more than four times compared to host PNCs. A combination of 3D-printed conversion layers containing green-, yellow-, and red-emitting doped PNCs with blue light-emitting diodes results in stable white light with superior color qualities. Hence, new composites with desired properties are developed as an alternative to conventional color phosphors.

Automated summary

A novel composite of CsPbBr3 perovskite nanocrystals doped with nickel thiocyanate is reported, demonstrating improved photoluminescence and extended stability. The addition of Ni(SCN)2 reduces surface trap states, resulting in increased photoluminescence quantum yield. These doped nanocrystals exhibit higher photoluminescence efficiency and can be used for stable white light emission.