Highly Emissive Lanthanide-Based 0D Metal Halide Nanocrystals for Efficient Ultraviolet Photodetector

Recently, lanthanide-based 0D metal halides have attracted considerable attention for their applications in X-ray imaging, light-emitting diodes (LEDs), sensors, and photodetectors. Herein, lead-free 0D gadolinium-alloyed cesium cerium chloride (Gd³⁺-alloyed Cs₃CeCl₆) nanocrystals (NCs) are introduced as promising materials for optoelectronic application owing to their unique optical properties. The incorporation of Gd³⁺ in Cs₃CeCl₆ (CCC) NCs is proposed to increase the photoluminescence quantum yield (PLQY) from 57% to 96%, along with significantly enhanced phase and chemical stability. The structural analysis is performed by density functional theory (DFT) to confirm the effect of Gd³⁺ in Cs₃Ce_{1- x}Gd_xCl₆ (CCGC) alloy system. Moreover, the CCGC NCs are applied as the active layer in UVPDs with different Gd³⁺ concentration. The excellent device performance is shown at 20% of Gd³⁺ in CCGC NCs with high detectivity (7.938 × 10¹¹ Jones) and responsivity (0.195 A W^-1) at -0.1 V at 310 nm. This study paves the way for the development of lanthanide-based metal halide NCs for next-generation UVPDs and other optoelectronic applications.