Material design and optical waveguide model development for fluorescent concentrator devices to improve the performance of perovskite solar cells

• Developed multi-colored CDs with high PLQY, significant Stokes shifts (≥1.13 eV), and excellent photothermal stability to enhance light harvesting in FSCs. • Established an optical waveguide structural model to evaluate the effects of waveguide geometry, layer count, and varying fluorescence incident angles on concentrator efficiency. • Introduced a five-layer equilateral triangular waveguide structure, achieving up to 100% light collection efficiency and overcoming the limitations of conventional refractive indices. • Integrated FSCs with HPSCs, reducing UV degradation and operational temperature, resulting in an optical efficiency of up to 16.95% and enhanced long-term stability. Halide perovskite solar cells (HPSCs) are a promising technology for solar energy conversion, owing to their low cost and high efficiency. However, their practical deployment is limited by instability and degradation under prolonged sunlight exposure. This study addresses these challenges by integrating fluorescent solar concentrators (FSCs) with HPSCs. FSCs, which combine fluorescent materials with an optical waveguide medium, offer a promising solution by enhancing light harvesting while reducing the direct exposure of solar cells. We present a multi-colored carbon dots (CDs)-based FSC designed to tackle key issues related to light efficiency, reabsorption, and stability. The CDs are synthesized to exhibit high photoluminescence quantum yield, substantial Stokes shifts, and excellent photothermal stability. Additionally, the optical waveguide structure is optimized through simulation tools to maximize light gathering efficiency. Simulation results demonstrate that a five-layered equilateral triangular waveguide structure can achieve up to 100% light gathering efficiency, effectively overcoming the limitations of traditional materials’ refractive indices. The integration of optimized FSCs with HPSCs reduces temperature stress mitigates UV degradation, and minimizes spatial footprint. The combination of the multi-colored CDs and optimized waveguide structure leads to a significant performance boost, achieving an optical efficiency of up to 16.95%. This work offers a cost-effective and scalable approach for improving the optical efficiency and stability of HPSCs, with promising applications in building-integrated photovoltaics, smart windows, and rooftop solar systems.