Optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has been considered as an ideal candidate for more efficiently harnessing solar energy. This focuses mostly on partitioning of the solar spectrum into ultraviolet/visible region for PV and infrared region for TE. Especially for PV-TE stack approaches, the TE part aims mainly for converting the transmission and thermali-zation losses from a sun-sided PV device to useful electrical energy.
Enhancing the utilization of solar energy and waste heat recovery are broad societal demand to resolve global energy crisis because the energy sources are readily accessible and abundant in contrast to wind, water, and pressure. Photovoltaic (PV)and thermoelectric (TE) devices have therefore been studied at the viewpoints of increasing the cell conversion efficiency and a thermoelectric figure of merit, respectively. However, their conversion performance still does not meet industrial requirements. One approach that has received considerable attention is to combine PV and TE for further improving the conversion efficiency by harvesting the waste heat generated from the sun-side PV part. In PV operation, ~40% of solar spectral irradiance is spontaneously transformed into heat by thermalization loss for high energy photons as well as transmission loss for low energy photons. Therefore, additional energy harvesting from the waste heat is useful not only for increasing the efficiency but also for removing the unwanted heat that prevents efficient PV operation.