Lattice Doping of Lanthanide Ions in Cs2AgInCl6 Nanocrystals Enabling Tunable Photoluminescence

Lead-free halide double perovskite Cs2AgInCl6 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 Dy3+, Sm3+, and Tb3+ ions into Cs2AgInCl6 nanocrystals (NCs) by the hot-injection method, bringing diverse PL emissions of yellowish, orange, and green light in Cs2AgInCl6:Ln3+ (Ln3+ = Dy3+, Sm3+, Tb3+). Moreover, benefiting from the energy transfer process, Sm3+ and Tb3+ ion-codoped Cs2AgInCl6 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 Cs2AgInCl6 NCs the unique and tunable PL properties and stimulate the development of lead-free halide perovskite materials for new optoelectronic applications.