Improving the performance of solar thermophotovoltaic (STPV) cells with spectral selected absorbers and small apertured radiation shields

An integrated analysis considering radiative energy transport among each component and carrier generation in the photovoltaic (PV) material is established for solar thermophotovoltaic (STPV) devices. STPV has been estimated with previous thermodynamics analysis to provide up to similar to 85% solar energy conversion efficiency (ECE) because of its capability to convert broadband solar radiation to narrowband thermal radiation that can be fully used with PV materials. However, in previous demonstrations, the ECE of STPVs is less than 10%, even with similar to 200 solar radiation concentrations. Based on our analysis, the maximum ECE of STPV without any radiation heat loss control is nearly zero when the solar concentration ratio is 1 and is similar to 18.78% when the solar concentration ratio is 10 0 0. Maximum ECE of STPV with spectral selected absorber optimized for 10 0 0 K level temperature, which has been proposed in recent STPV studies, can be similar to 9.56% when the solar concentration is 1 and can be similar to 31.72% when the solar concentration ratio is 10 0 0. Maximum ECE of STPV with our proposed multi-layered radiation shield to prevent radiative heat loss from the STPV to the ambient can provide ECE up to similar to 9.53% and similar to 57.02%, when the solar concentration ratio is 1 and 10 0 0, respectively. When we combine both the spectral selected absorber and our designed radiation shield, the ECE value of STPV can be up to similar to 20.65% and similar to 59.23% when the solar concentration ratio is 1 and 10 0 0, respectively. It is also observed that a similar to 1 mu m level bandwidth of photonic crystal (PhC), a device that can control the emission bandwidth, is required for STPV to achieve high ECE under each solar concentration ratio with difference radiative heat loss control. (c) 2021 Elsevier Ltd. All rights reserved.