Lattice Doping of Lanthanide Ions in Cs 2 AgInCl 6 Nanocrystals Enabling Tunable Photoluminescence

Lead-free halide double perovskite Cs 2 AgInCl 6 has become the research hotspot in the optoelectronic fields. It is a challenge to utilize the lattice doping by different lanthanide ions with rich and unique photoluminescence (PL) emissions for emerging photonic applications. Here, we successfully incorporated Dy 3+ , Sm 3+ , and Tb 3+ ions into Cs 2 AgInCl 6 nanocrystals (NCs) by the hot-injection method, bringing diverse PL emissions of yellowish, orange, and green light in Cs 2 AgInCl 6 :Ln 3+ (Ln 3+ = Dy 3+ , Sm 3+ , Tb 3+ ). Moreover, benefiting from the energy transfer process, Sm 3+ and Tb 3+ ion-codoped Cs 2 AgInCl 6 NCs achieved tunable emission from green to yellow orange and a fluorescent pattern from the as-prepared NC-hexane inks by spray coating was made to show its potential application in fluorescent signs and anticounterfeiting technology. This work indicates that lanthanide ions could endow Cs 2 AgInCl 6 NCs the unique and tunable PL properties and stimulate the development of lead-free halide perovskite materials for new optoelectronic applications.