Cerium-based halide nanocrystals towards fast high-energy radiation detection and sensitive temperature radiation sensing

Abstract

Rare-earth based luminescent materials offer rich electronic energy level structures, making them highly attractive for optoelectronic applications. Among them, all-inorganic cerium-based compounds such as Cs₃CeX₆ (X = Cl, Br, I) have garnered significant attention due to their high photoluminescence quantum yields and excellent structural stability. Herein, pristine and various metal ions-doped rare-earth cerium-based Cs₃CeBr₆ nanocrystals (NCs) were synthesized via a hot-injection method. By introducing Tb³⁺ (rare earth), Mn²⁺ (transition metal), and Sb³⁺ (main-group element), we achieved tunable dual emissions with distinct colors i.e., cyan, pink, and orange-yellow, respectively. Femtosecond transient absorption (fs-TA) spectroscopy reveals distinct luminescence mechanisms: host-to-dopant energy transfer dominates in the Tb³⁺/Mn²⁺ systems, while Sb³⁺ doping introduces an additional radiative recombination channel. We further fabricated Cs₃CeBr₆/polydimethylsiloxane (PDMS) flexible films, which exhibit excellent scintillation response and X-ray imaging capability under high-energy radiation. Additionally, we developed optical thermometers based on Tb³⁺-, Mn²⁺-, and Sb³⁺-doped Cs₃CeBr₆, as well as Sb³⁺-doped Cs₃CeCl₆ NCs. By comparing the temperature-dependent emission behaviors of host 5d-4f transitions and dopant-related f–f, d–d, and s-p transitions, the Sb³⁺-doped system demonstrates a maximum relative sensitivity (S_r) of 1.49%/K in the 90–210 K range. These results establish rare-earth cerium-based halide NCs as versatile platforms for multimodal radiation sensing, ranging from high-energy radiation detection to temperature-dependent photonic technologies.