Shuo Wang,Shuhan Zhang,Xin Li,Dan Huang,William W. Yu,Liang Wang
Near-infrared (NIR) emission underpins biomedical imaging, night vision, and optical communication. Yb 3+ -doped CsPbCl 3 have demonstrated ultrahigh photoluminescence quantum yields via quantum cutting, primarily enabled by a singular defect-assisted energy transfer pathway arising from the substitution of Pb 2+ by Yb 3+ . However, whether additional pathways exist to facilitate visible (VIS)-to-NIR conversion, thereby further enhancing the performance of NIR-emissive devices, remains an open and compelling question. Here, strategic engineering of localized bound excitons (BEs) is proposed in the thermally evaporated CsPbCl 3 :Yb system. Assisted BEs significantly promote energy transfer from CsPbCl 3 matrix to Yb dopants, unveiling a previously unknown excitonic energy transfer channel. Atomic-scale characterization combined with first-principles calculations uncovers a BE-driven excitonic transfer mechanism, specifically implicating Cs-vacancy-induced defects in mediating exciton behavior. These insights lead to the fabrication of high-performance NIR-LEDs with an 8.9% external quantum efficiency and 410 mW·Sr −1 ·m −2 radiance, marking a breakthrough in thermally evaporated NIR (>950 nm) light-emitting diodes.
Ran Peng,Yang Lurong,Hui Juan,Su Yirong,Chen Zeng,Zhu Haiming,Kuang Cuifang,Liu Xu,(Michael) Yang Yang
X-ray and near-infrared (NIR) imaging are two well-established noninvasive imaging techniques, whose fusion often delineates a more complementary view of the subject. In this study, we introduce an innovative dual-mode imaging approach using a NIR scintillator, functioning both as a conventional scintillator for X-ray imaging and as a light source for NIR imaging. Our method facilitates the concurrent acquisition and registration of X-ray and NIR images in a single X-ray shot, eliminating the need for additional hardware beyond that of a standard X-ray imaging system. We have successfully synthesized an ytterbium-doped perovskite NIR scintillator using a water-based scalable process, which exhibits a pronounced scintillation emission at 980 nm, suggesting the presence of a potential quantum cutting effect. The experimental results underscore the enhanced capabilities in visualizing features typically elusive in standard X-ray images, such as the vascular network in a human palm. Besides, our method can effectively separate the X-ray and NIR signals, which is a common issue with recently developed multi-band detectors that suffer from superimposed electrical signals. This separation is achieved by designing a NIR-Visible dual-band scintillator that channels the X-ray and NIR characteristics into distinct emission pathways, thus avoiding any potential interference between the two imaging modalities. This study presents a novel strategy for harnessing the synergistic information from X-ray and NIR photons, enabled by the simple yet effective design of a NIR X-ray scintillator. This advancement might hold the potential to broaden the application scope of conventional X-ray imaging, enhancing its diagnostic and analytical capabilities.
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