High-Efficiency Solar Hybrid Photovoltaic/Thermal System Enabled by Ultrathin Asymmetric Fabry-Perot Cavity.

Solar hybrid photovoltaic/thermal (HPT) systems maximize the overall solar energy conversion by simultaneously converting solar energy into electrical and thermal energy. However, the practical implementation of HPT systems is hindered by a lack of suitable optical materials capable of efficiently splitting the incident solar spectrum into the desired photovoltaic (PV) and photothermal (PT) bands. In this work, we provide the first demonstration of a multifunctional asymmetric metal-dielectric-metal (asym-MDM) optical coating to be used in an HPT system. The asym-MDM serves as the dual function of a quad-band spectrum splitter and a thermal receiver, leveraging on the multiorder spectral responses and the lossy nature of nickel. Moreover, silica aerogel is employed as a transparent insulting material to enhance the thermal storage capability, while the heat is effectively utilized for increasing the temperature difference of a thermoelectric generator (TEG). As a result, a simple and highly compact HPT system is developed, with simultaneous extraordinary heat mitigation of the single-junction amorphous silicon solar cell and heat generation at the hot side of the TEG. This leads to 63.9 and 370% performance improvements for the PV and PT subsystems at a solar concentration of 3, respectively. Asym-MDM will provide a low-cost yet high-efficiency solution for application of an HPT system in solar energy harnessing.