Scalable spectrally selective solar cell for highly efficient photovoltaic thermal conversion

Abstract

Photovoltaic/thermal (PV/T) hybrid technology offers significant potential for carbon neutrality by simultaneously converting photons into electricity and heat simultaneously. However, the mismatch between PV/T output temperature and the temperature demand across a wide range of scenarios limits its practical uses. Traditional PV cells have high infrared emissivity, resulting in significant heat losses and seriously significantly hindering the development of PV/T systems. Spectrally selective solar cells characterized by high solar absorption, low thermal emission, and photoelectric conversion process, have yet to be realized thus far. In this study, we propose an integrated design and develop a scalable industrial approach for fabricating meter-scale spectrally selective solar cell with a high solar absorptivity of 92.3 % and a low infrared emissivity of 20.3 %, achieving the highest absorption-emission ratio of measured 4.6 experimentally. The primary novelty of the design lies in integrating the PV cell electrode atop and low-emissivity layer into one eliminating the need for rare metals and reducing complexity. Furthermore, we demonstrate that the spectrally selective PV/T significantly increases the overall solar efficiency from 13.7 % to 82.5 % and reduces the heat loss coefficient to 3.55 W/(m^2.K). The validated model accurately captures the high photovoltaic thermal efficiency, enabling new technological advancements.