Li ⁺ ‐Mediated Topological Regulation of Aluminosilicate Glass Ceramics: Near‐Full Crystallinity for Multifunctional Optoelectronic Applications

Developing glass ceramics (GCs) with ultrahigh crystallinity and excellent optical transparency remains a formidable challenge due to the intrinsic trade‐off between crystalline volume fraction and grain boundary light scattering. Herein, a Li + ‐ doping mediated topological network regulation strategy is developed to address this dilemma in MgO‐Al 2 O 3 ‐SiO 2 transparent GCs (TGCs). Combined experimental characterizations and molecular dynamics simulations confirm that Li + acts as a network modifier to relax the rigid tetrahedral framework, tailor Al coordination, and optimize crystallization kinetics. This boosts crystallinity from 5.6 to 97.0 vol% (near‐full crystallinity) while retaining high transparency via refractive index matching between the crystal and residual glass. Eu 2+ ‐activated high‐crystallinity TGCs exhibit superior multifunctional optical performance, including a high internal quantum efficiency of 63%, good resistance to thermal quenching (82% intensity retention at 150°C), and a high x‐ray light yield of 5740 photons/MeV. Their practical applicability is further validated for high‐power indoor/horticultural lighting and high‐resolution x‐ray scintillation. This work establishes a universal topological engineering paradigm for the rational design of glass network topologies, which provides a new solution to the transparency‐crystallinity trade‐off in GCs and paves the way for next‐generation high‐performance TGCs‐based optoelectronic devices.