Alkynyl Copper(I) Nanoclusters with Thermally Activated Delayed Fluorescence as Efficient Scintillator for X ray Imaging
Jun-Jie Fang, Zheng Liu, Yu Zhang, Zhi-Yi Wang, Yun-Peng Xie* & Xing Lu*
SCIENCE CHINA Chemistry
https://www.sciengine.com/SCC/doi/10.1007/s11426-025-2615-x
Abstract
Copper(I) nanoclusters (NCs), compared to other commercially scintillators, exhibit ease of synthesis and cost-effectiveness, demonstrating significant potential for application as X-ray scintillators. However, synthesizing atomically precise alkynyl copper(I) NCs with high luminescence is still challenging. Here, eight propeller-shaped Cu9 NCs were successfully synthesized. Each features a unique triangular prismatic Cu6 core, which exhibits significant structural differences compared to other copper(I) halide NCs. By modifying with triphenylphosphine derivatives and halogens, the Cu9 NCs exhibited their highest photoluminescence quantum yield (PLQY) of 43% for 2-CF3. Comprehensive structural elucidation alongside photophysical and computational analyses have unveiled the mechanisms underlying the thermally activated delayed fluorescence (TADF) performance of these Cu9 NCs. A white LED fabricated using 2-CF3 powder demonstrates a color rendering index (Ra) of 73.5. Notably, the radioluminescence (RL) of 2-CF3 was found to demonstrate a scintillating light yield of 4924 photons/MeV and a low detection limit of 1.239 μGy/s. Furthermore, the X-ray imaging resolution of 25.4 line pairs/mm was reported for the 2-CF3 screen, representing the highest resolution achieved so far for organic-inorganic hybrid scintillators. This investigation not only represents the first observation of TADF and RL behaviors in alkynyl copper(I) NCs but also provides new insights into advancing scintillator design.
