Wearable luminescent solar concentrators based on carbon dots crosslinked hydrogels

Wearable luminescent solar concentrators (LSCs) hold significant promise for integrating energy harvesting with flexible textiles. However, most currently reported LSCs are either rigid or liquid-filled, making it challenging to achieve flexible devices with high efficiency and mechanical robustness. Here, we introduced Ca²⁺-capped carbon dots (C-dots) as dual-functional agents, simultaneously crosslinking sodium alginate hydrogels and serving as luminophores, eliminating the need for additional dopants. The resulting hydrogels exhibited tunable mechanical strength (0.25 MPa at 50 % strain), high transparency (64 % visible transmittance), and good stability. As a proof-of-concept, we fabricated wearable LSCs by embedding the hydrogel into flattened polyvinyl chloride tubes and weaving them into textiles. Under natural sunlight illumination (50 mW/cm²), the as-fabricated flexible LSC achieved a power conversion efficiency (ηPCE) of 0.26 % and an optical efficiency (ηopt) of 2.60 % with 64 % average visible transmittance. Remarkably, the device retains 72 % of its initial optical efficiency after 24 h continuous ultraviolet illumination (468 mW/cm2). This work demonstrates the first hydrogel-based LSCs for practical wearable energy harvesting.