Energy Transfer Engineering Enabled Efficient and Broad-Band Near-Infrared Emission
Xuemin Wen, Yujie Wang, Romana Kučerková, Vladimír Babin, Petr Průša, Monika Kotyková, Tianchi Wang, Xuhui Xu, M. Nikl, Yuntao Wu
Abstract
Near-infrared (NIR) light is crucial for medical diagnostics, industrial inspection, and military applications, but achieving both broad-band and efficient NIR luminescence remains challenging. Here, we propose an energy transfer strategy in low-dimensional halides to enable efficient NIR emission, exemplified by zero-dimensional Cs 4 CaI 6:Yb 2+,Sm 2+ . The optimized Cs 4 CaI 6:1%Yb,3%Sm single crystals exhibit high internal and external quantum efficiencies of 73.3% and 47.8% in the NIR region, respectively, resulting from effective Yb 2+ →Sm 2+ energy transfer. When integrated with a commercial blue-light-emitting chip, a record NIR photoelectric conversion efficiency of 31.0% is achieved. Moreover, Cs 4 CaI 6:1%Yb,3%Sm exhibits an exceptional scintillation efficiency of 52,000 photons/MeV, representing a state-of-the-art performance among NIR scintillators. Its bright NIR scintillation enables clear imaging with polydimethylsiloxane-based scintillation screens, even under ambient light conditions, paving the way for portable outdoor X-ray imaging. This work provides an effective approach to achieve NIR emission for light-emitting diodes and scintillation applications.