Enhancing the efficiency of CsPbX3 (X = Cl, Br, I) nanocrystals: Via simultaneous surface peeling and surface passivation

Abstract

Inorganic CsPbX<inf>3</inf> (X = Cl, Br, I) perovskite nanocrystals (PNCs) are promising materials for next-generation optoelectronic applications due to their tunable emission and high color purity. However, there is still room to improve their photoluminescence quantum yields (PLQYs) in order to promote their applications. Herein, the PLQY of blue light emitting CsPb(Cl/Br)<inf>3</inf> PNCs was increased to 83% with ammonium hexafluorophosphate by choosing an appropriate treatment time. The salt peeled off the outermost surface of PNCs with halide vacancies and then passivated the surface. This method is effective at improving the PLQYs of different CsPbX<inf>3</inf> (X = Cl, Br, I) PNCs covering the entire visible spectrum; the PLQYs were improved to 25% for CsPbCl<inf>3</inf> at 398 nm, 83% for CsPb(Cl/Br)<inf>3</inf> at 448 nm, 96% for CsPbBr<inf>3</inf> at 504 nm, 86% for CsPb(Br/I)<inf>3</inf> at 568 nm, and 98% for CsPbI<inf>3</inf> at 687 nm.