Enhanced Light Harvesting and Photovoltaic Output in Perovskite Solar Cells via Methyltrimethoxysilane-Modified Porous Silica Anti-Reflective Coatings

Anti-reflective coatings (ARCs) offer an effective strategy to increase the electrical energy output of perovskite solar cells (PSCs) by improving light harvesting without altering device architecture. Here, MTMS-modified porous SiO2 ARCs were fabricated through a sol–gel process to simultaneously optimize optical transmittance and photovoltaic performance. The hybrid modification produced a porous cross-linked network with optimized transmittance, while dip-coating and thermal treatment enabled regulation of film thickness and microstructure. The optimized coating exhibited an average transmittance of 98.23% and a peak transmittance of 99.67% over 400–800 nm, along with a water contact angle of 100°, and it also improved wear resistance. When integrated onto the rear non-conductive glass side of FTO glass substrates for perovskite solar cells, the ARC significantly enhanced light harvesting, the ARC significantly enhanced light harvesting, increasing the short-circuit current density from 24.12 to 24.93 mA cm−2, while leaving Voc and FF essentially unchanged, resulting in a power conversion efficiency improvement from 23.44% to 24.27%. EQE analysis confirms that the performance enhancement originates from increased photon utilization rather than changes in internal electrical properties. Energy-yield analysis further predicts an additional 4.278 × 106 kWh of annual electricity generation for a representative 100 MW photovoltaic plant, demonstrating that front-side optical engineering is a practical route toward higher-energy-output perovskite photovoltaics.