Rare Earth Single‐Atomic Hybrid Glasses for Near‐Infrared II Optical Waveguides

The increasing demands for modern information communication and storage necessitate the development of near-infrared (NIR) active optical waveguides. However, achieving efficient NIR emission with minimal optical loss remains a critical challenge. Herein, we present a new class of rare earth single-atomic hybrid glasses, synthesized via bottom-up self-assembly, as a solution to these limitations. By harnessing the ultralong phosphorescence of Nd³⁺-doped complex glasses, these materials achieve NIR-II emission extending to 1.32 µm with a photoluminescence quantum yield (PLQY) of ∼5.7%, setting a new record among state-of-the-art rare-earth-based complexes in the NIR-II region. This exceptional performance stems from the efficient sensitization of Nd³⁺ ions in hybrid glass, with a phosphorescence energy transfer efficiency of 93.55%. Furthermore, these transparent and flexible hybrid glasses trigger optical waveguiding in Eu³⁺- and Nd³⁺-doped microstructures, enabling ultralow-loss coefficients of 0.978 dB mm^-1 at 819 nm and 5.1 dB mm^-1 at 1048 nm, respectively. Therefore, this work not only demonstrates that metal-organic complex glasses with ultralong phosphorescence can effectively serve as sensitizer matrices for boosting NIR-II emission, but also supports the fabrication of 1D and 2D glassy microstructures with ultralow-loss optical waveguiding for advanced NIR-II photonic applications.