Sol–gel preparation of light scattering monolithic silica plates and their application to photovoltaics

Abstract

This study proposes a concentrating photovoltaic (PV) device that generates power solely through the scattering of incident light. Due to its translucent or opaque nature, this system is uniquely suited for building-integrated photovoltaics, such as power-generating frosted glass. A key advantage is the facile fabrication of light-scattering structures using a simple sol–gel method. Monolithic silica plates were easily synthesized from an aqueous tetramethylammonium silicate solution. Two approaches to induce light scattering were demonstrated: transferring surface roughness from abrasive paper during molding, and dispersing high-refractive-index TiO₂ nanoparticles within the silica matrix. Edge-mounted monocrystalline silicon PV module was evaluated under the simulated solar irradiation. Compared to a device using a flat silica plate as control (short-circuit current, I_SC = 11.6 mA), the rough-surfaced silica significantly enhanced the photocurrent, achieving an I_SC of 18.2 mA in a face-down configuration due to improved light-trapping and confinement efficiencies. Similarly, dispersing TiO₂ nanoparticles at a low concentration of 0.07 wt % increased the I_SC to 25.6 mA. This simple sol–gel strategy offers a highly practical and environmentally friendly pathway for developing translucent solar-harvesting building materials.