Tailored Doping in Ionic Crystals for the Development of Color-Tunable Metal Halides through Solid-State Reactions

The rapid development of metal halides (MHs) in recent years has attracted significant attention. Doping, as a potent method for inducing new material properties, has also been extensively studied. This study focuses on the importance of doping as a universal strategy in the realm of optically active MHs in solid-state reactions. The method successfully incorporates 18 dopant ions into 12 MH hosts; a total of 34 doped MHs are achieved using the ball-milling method with the doping level approximately remaining at 5%. By strategically doping various ions, including Ag+, Sn2+, Mn2+, Ga3+, Sb3+, Cr3+, Te4+, Zr4+, Nd3+, Tm3+, Yb3+, Pr3+, Er3+, and W4+ into the B-site of three distinct host materials (Rb4CdCl6, Cs2ZnCl4, Cs2NaInCl6), we demonstrate the effectiveness and broad applicability of mechanochemical doping across different structures, achieving spectral tuning from 450 to 1550 nm. Moreover, doped MHs show a relatively enhanced trend in thermal stability compared to pristine MHs, which is attractive for the screening of emitters applied in solid-state lighting and displays. Consequently, this provides a straightforward and simple pathway for obtaining efficient light-emitting materials for optoelectronic applications.