Exploiting structural benefit of double phosphate for extremely efficient near-ultraviolet light towards multiple functionality
Conglin Liu, Xiaoting Huang, Jing Zhu, Yubin Wang, Lei Lei, Asif Ali Haider, Guanhao Zhou, Ran Li, Xiaoyang Zhao, Wei Qian, Dandan Gao, Yue Qin, Zhi Xie
Abstract
Despite advances in multicolor luminescence of Ce-activated materials, achieving efficient and stable near-ultraviolet (n-UV) emission remains a critical challenge. Here, based on structural rigidity engineering, the small Stokes shift (Δ<em>S</em><em> </em>= 0.53 eV) of Ce<sup> </sup>in microwave-hydrothermally synthesized NaSrY(PO<sub>4</sub>)<sub>2</sub> (NSYP) nanophosphors is achieved, addressing this shortage. The internal quantum efficiency reaches as high as 98.5% (λ<sub>ex</sub> = 325 nm) along with superior thermostability (78% intensity retention at 423 K) and exceptional solvent resistance (82% after 10-day immersion). The optimal nanomaterial is used as a scintillation screen for X-ray imaging, achieving a high spatial resolution of 11.0 lp/mm and clear imaging of measured objects, rivaling commercial scintillator (CsI:Tl). A high relative sensitivity (S<sub>R-max</sub> = 0.94% K<sup>−</sup><sup>1</sup>) is achieved for excitation intensity ratio (EIR) technology-based optical thermometry. The work presents fascinating applications in X-ray imaging and optical thermometry for n-UV-emitting nanophosphors. It also highlights the critical role of host structure in designing high-quality Ce-activated optical materials.