A New Type Back Contact Solar Cells Based on Si Wafer and Combined with the Multilayer MoOx/Ag/MoOx and Cesium Carbonate Films

32nd European Photovoltaic Solar Energy Conference and Exhibition; 656-659
We present a new dopant-free back contact solar cells combined with the multi-functional emitter MoOx (20 nm)/Ag (15 nm)/MoOx (10 nm) (MAM) and 3nm Cs2CO3 as back surface field (BSF). The initial efficiency of 14.06% has been achieved, featuring the short circuit current density of 36.4 mA/cm2, open-circuit voltage of 591 mV and FF of 65.37% under STC (AM 1.5 global spectrum, 25 °C and 1000 W/m2) on the 4 cm2 area single side textured FZ n-Si. The front textured surface is passivated by plasma-enhanced chemical vapour deposition (PECVD) 70 nm SiNx and thermal oxide 10 nm SiO2. The rear-side 100 m interdigital gap, 250 m half-width electrode/Cs2CO3 and 750 m half-width electrode/MAM are deposited by thermal evaporation with accurate control by metal masking instead of high temperature diffusion and photolithographic masking. In order to achieve higher efficiency, we analyze the power loss, due to the front surface recombination velocity can be reduced to S=2.9 cm/s, the main losses of JSC are the light escape and back surface recombination. Additionally, the trend of series resistance changing with voltage is different from the homojunction back contact solar cells.