Highly Transparent and Color-Neutral Eu3+-Doped Glass Luminescent Solar Concentrators for Scalable BIPV Integration

Abstract

As urban design increasingly prioritizes energy efficiency and sustainability, building-integrated photovoltaics (BIPVs) have emerged as a compelling approach for on-site solar energy harvesting. Among these, luminescent solar concentrators (LSCs) offer transparent and architecturally compatible solutions by guiding spectrally shifted light to edge-mounted photovoltaic cells. In this study, we report the first demonstration of a rare-earth doped (Eu³⁺) fully inorganic glass based LSCs, combining high optical performance, long-term environmental stability, and process scalability. By tuning Eu³⁺ concentration, waveguiding losses are minimized, and emission efficiency and photon transport is maximized. Devices fabricated with the optimal glass composition (2.5 mm thick; 2×2 to 6×6 cm² ) exhibit outstanding average visible transmittance (AVT ≈ 90%) and near-neutral color rendering (CRI ≈ 98), enabling seamless integration into modern architectural environments. The glass matrix maintains its optical and structural integrity under thermal, chemical, and mechanical stress, confirming its long-term durability for real-world applications. External photon efficiency remains stable at ~6.4% across all device sizes, while the highest power conversion efficiency (PCE) of 0.852% in 4-edge configuration is achieved for the most compact device. These findings position Eu³⁺-doped glass as a robust, scalable, and multifunctional platform for the next generation of BIPV-integrated LSCs, offering a rare-earthbased solution for durable, visually neutral solar harvesting surfaces.