posted on 2024-01-26, 15:33authored byTong Cai, Wenwu Shi, Rongzhen Wu, Chun Chu, Na Jin, Junyu Wang, Weiwei Zheng, Xinzhong Wang, Ou Chen
The
introduction of lanthanide ions (Ln3+) into all-inorganic
lead-free halide perovskites has captured significant attention in
optoelectronic applications. However, doping Ln3+ ions
into heterometallic halide layered double perovskite (LDP) nanocrystals
(NCs) and their associated doping mechanisms remain unexplored. Herein,
we report the first colloidal synthesis of Ln3+ (Yb3+, Er3+)-doped LDP NCs utilizing a modified hot-injection
method. The resulting NCs exhibit efficient near-infrared (NIR) photoluminescence
in both NIR-I and NIR-II regions, achieved through energy transfer
down-conversion mechanisms. Density functional theory calculations
reveal that Ln3+ dopants preferentially occupy the Sb3+ cation positions, resulting in a disruption of local site
symmetry of the LDP lattices. By leveraging sensitizations of intermediate
energy levels, we delved into a series of Ln3+-doped Cs4M(II)Sb2Cl12 (M(II): Cd2+ or Mn2+) LDP NCs via co-doping strategies. Remarkably,
we observe a brightening effect of the predark states of Er3+ dopant in the Er3+-doped Cs4M(II)Sb2Cl12 LDP NCs owing to the Mn component acting as an intermediate
energy bridge. This study not only advances our understanding of energy
transfer mechanisms in doped NCs but also propels all-inorganic LDP
NCs for a wider range of optoelectronic applications.