Perovskite energy funnels for efficient white emission.

Doping Mn into CsPbCl nanocrystals (NCs) yields strong orange emission, while the related emission in Mn doped CsPbBr NCs is impaired seriously. This is mainly ascribed to back energy transfer from the Mn dopant to the host. Doping Mn into perovskites with multiple-quantum-well (MQW) structures may address this issue, where the energy funnels ensure a rapid energy transfer process, and thus resulting in a high photoluminescence quantum yield (PLQY). Here, we have developed an Ag assisted Mn doping method in which Mn can be easily doped into Br-based MQW perovskites. In this MQW perovskites, both nanoplatelets (NPLs) and NCs were formed simultaneously, where efficient energy transfer occurred from the NPLs with a higher energy bandgap to the NCs with a smaller energy bandgap, and then to the Mn dopants. White lighting solution with a PLQY up to 98% has been acquired by altering the experimental parameters, such as reaction time and the Pb-to-Mn feed ratio. The successful doping of Mn into CsPbBr host has great significance and shows promising application for next-generation white lighting.