Abstract
The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. Achieving lossless coupling makes the power output from the hybrid device equal to the sum of the maximum power outputs produced separately from individual PV and TE devices. TE devices need to have low internal resistances enough to convey photo-generated currents without sacrificing the PV fill factor. Concomitantly, a large number of p-n legs are preferred to drive a high Seebeck voltage in TE. Our simple method of attaching a TE device to a PV device has greatly improved the conversion efficiency and power output of the PV device (~30% at a 15°C temperature gradient across a TE device).
Highlights
The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy
The PV devices used in our hybrid circuits were conventional crystalline Si solar cells with an open-circuit voltage (Voc) of 0.592 V, a short-circuit current density (Jsc) of 30 mA/cm[2], and a conversion efficiency of 12.5% under AM 1.5 G normal illumination of 100 mW/cm[2] at room temperature (25uC)
Our theoretical and experimental results indicate that resistance matching is of significant importance for optimal operation of a hybrid circuit
Summary
The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. One promising approach to further improve conversion efficiency is to combine PV and TE devices This would allow harvesting of a larger spectrum of solar energy along with the waste heat generated from the solar facing PV19–25. The maximum power output was lower than the sole PV output because the fill factor (FF) of the hybrid circuit decreased due to the internal resistance of the TE device without additional voltage gains. Upon optimizing the hybrid circuit (lossless coupling), we observed a remarkable improvement in the PV www.nature.com/scientificreports device: its efficiency increased by ,30% (conversion efficiency of 16.3%) with only a 15uC temperature gradient across the TE device
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