Transmissive concentrator multijunction solar cells with 47{\%} in-band efficiency for a hybrid photovoltaic-solar thermal system

Transmissive concentrator multijunction (TCMJ) solar cells with over 47{\%} in-band power conversion efficiency (PCE) have been demonstrated. The illuminated I-V test under concentrated 500-sun solar spectra have shown that the PCE of the TCMJ solar cells for in-band light (photon energy above the cell's lowest bandgap) can reach up to 47.6{\%} (29.5{\%} for the full solar spectrum). Temperature coefficients of several parameters (open circuit voltage, short circuit current, fill factor) have been derived under 1 sun and 500 suns, showing linear variations versus temperature change. Optical measurements indicate that the cells show 76.5{\%} solar-weighted optical transmission for the out-of-band light (photon energy below the cell's lowest bandgap). This TCMJ solar cell exhibits promising spectrum splitting capability, which has potential for use in hybrid photovoltaic-solar thermal energy conversion systems.