Anti‐Solvent Synthesis of Three‐Color Indium‐Based Halide Perovskite Microplate/Microcrystal Phosphors for High Color Rendering WLEDs

Abstract Lead‐free halide perovskites are emerging as promising eco‐friendly candidates for next‐generation solid‐state lighting because of their nontoxicity and availability for broad emission. Herein, a modified room‐temperature anti‐solvent precipitation method is developed to synthesize the Sb³⁺‐doped, In‐based, lead‐free halide perovskites in microplate/microcrystal structure with different emission colors. The layered structure of InCl₃ serves as the template for the growth of Cs₂InCl₅(H₂O):Sb³⁺ microplate phosphors. Moreover, the presence of HCl not only improves the solubility of precursors, but also provides the acid etching effect. The resultant Sb³⁺‐doped Cs₂InCl₅(H₂O) microplate phosphors show bright yellow emission with photoluminescence quantum yield up to 92.4%. Furthermore, Cs₃InCl₆:Sb³⁺ and Cs₂NaInCl₆:Sb³⁺ are synthesized through the similar method, which displays the bright green and deep‐blue emission, respectively. Subsequently, the proof‐of‐concept white light‐emitting diodes (WLEDs) are fabricated based on Cs₂NaInCl₆:Sb³⁺ + Cs₂InCl₅(H₂O):Sb³⁺ and Cs₂NaInCl₆:Sb³⁺ + Cs₃InCl₆:Sb³⁺ + Cs₂InCl₅(H₂O):Sb³⁺ phosphors, which achieves high‐quality white light with the color rendering index (CRI) of 91.6 and 95.4, respectively. The results greatly advance the development of lead‐free halide perovskite phosphors synthesis, which may offer new possibilities for high CRI WLEDs fabrication.