Codoping of Lead‐Free Double Perovskites Promotes Near‐Infrared Photoluminescence

In the rapidly developing smart era, near‐infrared luminescent materials have important applications in various fields that are closely related to people. Nag and co‐workers provided a first codoping strategy to achieve efficient near‐infrared photoluminescence in lead‐free double perovskite materials. Through the introduction of Bi 3+ ions, a new energy state is formed that leads to the absorption of lower‐energy light. The excited state formed by this light absorption subsequently excites f‐electrons of Er 3+ or Yb 3+ ions, and the relaxation of these f‐electrons results in near‐infrared photoluminescence. This may open a new chapter in the application of perovskites for infrared detection and human sensing.