CsPbBr₃:Mn Nanowires: d-d Transfer of Mn Ions for Bright White Emitting Diodes

Bright and stable multicolor emission is expected for applications in light-emitting diodes. In this paper, CsPbBr 3:Mn nanowires (NWs) with bright blue and orange emissions were created via bandgap and component adjustment. Pure CsPbBr 3 NWs with an average diameter of 3.3 nm, prepared at room temperature, revealed a sharp absorption peak and a narrow blue emission spectrum. The photoluminescence (PL) peak position of CsPbBr 3 NWs was changed from 443 to 469 nm via ion-exchange reactions using HBr at different concentrations. Different from green-emitting CsPbBr 3 nanocrystals, the quantum size effect of one-dimensional CsPbBr 3 NWs resulted in the bandgap blue-shifting to 2.61 eV, which provided the prerequisite for Mn doping into CsPbBr 3 NWs. Br ion exchange enabled Mn ions to enter into the lattice. Fluorescence lifetime measurements helped us to study the d-d transfer of Mn. During Mn doping, the exciton energy transformation from CsPbBr 3 NWs to Mn caused the d-d transfer of Mn, resulting in the orange emission of Mn (615 nm) observed in the NWs. The PL quantum yield of the NWs after Mn doping was 58.7%, which is more than 2 times that of pure CsPbBr 3 NWs. These bright CsPbBr 3:Mn NWs with blue and orange emissions were used to prepare white-light-emitting diodes with Commission Internationale de l’Eclairage color coordinates of (0.320,0.291).