Controlling Mn Emission in CsPbCl₃ Nanocrystals via Ion Exchange toward Enhanced and Tunable White Photoluminescence

Abstract

Although inorganic cesium halide lead perovskite nanocrystals (NCs) exhibited tunable photoluminescence (PL), it is still a challenge for such NCs with multicolor and white emission for application. In this article, as-synthesized Mn:CsPbCl3 NCs were treated using an oleoamine solution of CdX2 (X = Cl, Br) to get a high PL quantum yield (PLQY) and stability. CdCl2 passivated the surface defects of Mn:CsPbCl3 NCs through anion exchange to get high PL intensity, especially to increase Mn emission. The PLQY of the sample was increased from 15 to 85% after ion exchange. Furthermore, the treatment of CdBr2 resulted in the appearance of a powerful blue emission peak, and the PLQY increased to 95.7%. The PL decay kinetics of samples was studied before and after treatment. Mn2+ emission in Mn:CsPb(Cl/Br)3 NCs was increased because of the reaction of CdBr2 and Mn:CsPbCl3 NCs. Interestingly, the tunable and bright white emission from Mn:CsPb(Cl/Br)3 NCs was obtained by controlling the amount of Br. The controlling of Mn emission plays an important role in changing the Commission Internationale de l’Eclairage color coordinates. Because of bright and tunable PL, the NCs may be used in white-light-emitting diodes.