Impact of TiO2 on performance and thermal characteristics of bifacial solar modules: A computational and experimental approach

Temperature-induced efficiency degradation poses a persistent challenge for silicon photovoltaic (PV) modules, especially under high-irradiance conditions. Radiative cooling has recently gained attention as a promising passive strategy for thermal management without additional energy input. In this study, TiO2 thin films were applied as radiative cooling layers on silicon modules, and their thermal behavior was systematically analyzed through the finite difference method (FDM). The calculation results revealed temperature reductions of 2.3 degrees C and 4.0 degrees C for 10 nm and 50 nm TiO2 layers, respectively, driven by both enhanced radiative emission and optical reflection losses. These two effects were independently evaluated to identify the optimal layer thickness. To validate the calculation results, outdoor experiments were conducted using modules integrated with TiO2 coatings. A temperature drop of 0.9 degrees C was observed under real-world conditions, accompanied by an 11 %p energy yield in the module stage. This work demonstrates that integrating a thin TiO2 layer offers a practical and scalable approach to suppress thermal stress in silicon PV modules, ultimately contributing to improved energy yield and long-term stability.