Optical modelling and energy-yield assessment of UV down-shifting layers for high-efficiency TOPCon solar modules

The transition of the photovoltaic industry towards n-type TOPCon technology has increased interest in ultraviolet (UV)-induced degradation mechanisms affecting both solar cells and module materials. While conventional UV absorbers can mitigate degradation, they also reduce photocurrent generation by removing a portion of the incident solar spectrum. Luminescent UV down-shifting (UVDS) layers offer an alternative approach by absorbing harmful UV photons and re-emitting them at longer wavelengths, where silicon solar cells exhibit higher conversion efficiency. In this work, we present an experimentally calibrated and validated comprehensive optical modelling framework for simulation of UVDS layers integrated into n-type TOPCon solar cells and modules. The model was calibrated using experimentally characterized UVDS layers based on luminescent dyes embedded in a polyolefin elastomer matrix and validated through comparison with measured external quantum efficiency data. Parametric simulations identified dye concentration and photoluminescent quantum yield as the key parameters governing UVDS performance. The results show that UVDS layers capable of absorbing approximately 90% of incident UV radiation introduce photocurrent losses below 1%, while providing more than 2% photocurrent gain relative to conventional UV-blocking layers with comparable absorption characteristics. The validated modelling framework was further applied to long-term energy-yield simulations and realistic module geometries, demonstrating its usefulness for the analysis and optimization of UVDS-enhanced photovoltaic devices and modules.