Blue-emitting perovskite nanocrystals with enhanced optical properties through using NaBH₄

APbX 3 -type [A = CH 3 NH 3 + (MA + ), NH 2 CH=NH 2 + (FA + ), X = Cl – , Br – , I – ] organic–inorganic perovskite nanocrystals (PeNCs) have superior optical properties, such as emission with a narrow full width at half maximum and emission color tunability over the entire visible range. However, blue-emitting PeNCs [APb(Br/Cl) 3 ] exhibit low photoluminescence quantum yields owing to Cl defects, hindering their practical applications. The Cl defects induce nonradiative recombination caused by the trap levels formed deep in the band gap. Herein, we report the preparation of blue-emitting PeNCs that exhibit excellent optical properties by using NaBH 4 to decrease the number of Cl defects.