Enhancing Passive Radiative Cooling Performance on Solar Panels via Multiple Scattering Effects in Aggregated Silica Particles/Polydimethylsiloxane Films

Photovoltaic (PV) technology has become a crucial component of the global move toward clean energy, offering a power source that is sustainable, scalable, and increasingly cost-effective. However, thermal degradation of solar cells under elevated operating temperatures remains a critical challenge. This study reports a zero-energy passive daytime radiative cooling (PDRC) approach to mitigate this issue using a high-performance transparent cooling film. The film incorporates hierarchically structured aggregated dense silica (ADS) particles embedded within a polydimethylsiloxane (PDMS) matrix, i.e., the ADS/PDMS film. ADS particles, synthesized via a spray-drying process, exhibit a distinctive porous architecture composed of nanoscale building blocks, enabling enhanced spectral selectivity. The ADS/PDMS films maintain considerable visible transparency across the crystalline-silicon absorption band to maximize power generation while achieving high near-infrared (NIR) reflection through Mie resonance and multiple scattering within the ADS architecture and exhibiting high emissivity in the 8–13 μm atmospheric transparency window. Outdoor evaluations conducted under different atmospheric conditions confirmed the reliable performance of the ADS/PDMS films, which consistently reduced operating temperatures of solar panels up to 7.5 °C on average and improved open-circuit voltages (Voc) by about 3.56%. These results demonstrate that ADS design provides an effective framework for advanced passive thermal management, contributing to enhancing the PV and long-term operational stability.