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, CsPbBr3:Mn nanowires (NWs) with bright blue and orange emissions were created via bandgap and component adjustment. Pure CsPbBr3 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 CsPbBr3 NWs was changed from 443 to 469 nm via ion-exchange reactions using HBr at different concentrations. Different from green-emitting CsPbBr3 nanocrystals, the quantum size effect of one-dimensional CsPbBr3 NWs resulted in the bandgap blue-shifting to 2.61 eV, which provided the prerequisite for Mn doping into CsPbBr3 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 CsPbBr3 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 CsPbBr3 NWs. These bright CsPbBr3: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).