Energy-efficient colorful silicon photovoltaic modules driven by transparent-colored radiative cooling

Abstract

Building-integrated photovoltaics (BIPVs) shows attractive potential in utilizing solar energy and easing the global greenhouse effect. However, the strong absorption of traditional silicon (Si) photovoltaic (PV) modules makes the high surface temperature and keeps the black appearance. For the current BIPVs, improving the power conversion efficiency (PCE) of Si PV modules with aesthetic requirements remains a great challenge. Herein, we design a novel transparent-colored radiative cooling nanocomposite coating that can be applied to the cover glass of Si PV modules. The functional coating consists of the non-metallic nanoparticle (Si@SiO2 core-shell nanoparticle) for the structural coloration of PV modules and poly (methyl methacrylate) (PMMA) as the matrix. The Si@SiO2 core-shell nanoparticle with Mie resonance selectively reflects visible light to generate a structural color. The PMMA exhibits high transmittance above the bandgap of the Si solar cell and good emittance in the mid-infrared region. The simulated results show that the colored PV modules with integrated coatings display a wide range of colors in the CIE−1931 color space and the PCE loss reduction of all the colored PV modules is less than 10%. Meanwhile, the solar transmittance above the Si bandgap T‾solar > 0.9 and the emittance in the atmospheric window ε‾IR > 0.95. The equilibrium temperature of Si PV modules with functional coatings is only 2∼3 K higher than the ideal minimum. This work provides an alternative and convenient method to design the structural colored PV module with radiative cooling for effectively balancing PV module color and PCE, promoting the development of BIPVs.