Bifacial Tandem Solar Panels with MOS Cells on the Backside for Applications in Deserts

Abstract

This work proposes bifacial tandem solar panels with MOS cells on the backside aiming at applications in deserts. MOS solar cells were fabricated using Al(200nm)/ Mg(30nm)/SiO2 (1.73nm)/Si-p structures. The gate oxide was grown by rapid thermal processing (RTP) and the main parameters studied were extracted by means of electric characterization through IxV curves of the MOS solar cells. For the operation temperature of the MOS cell varying from 25°C to 70°C, it was shown that the loss of the conversion efficiency ($\eta$) was at least 25% lower compared to conventional solar modules based on PN junctions and multi-crystalline-Si [9, 12]. As a result, the use of MOS solar cell on the backside of two different generations of CdS_CdTe cells with different conversion efficiencies at 25° C (15.8% and 21.0%), operating at the typical temperature of 70°C in deserts, promotes the increase of the conversion efficiency of 10.0% for CdS_CdTe1 (15.8%) and 6.0% for CdS_CdTe2 (21.0%).