Carrier transport in PEDOT:PSS/n-Si heterojunction solar cells

Abstract

We have investigated solution-processed n-type silicon (n-Si) heterojunction solar cells with a transparent hole-conducting polymer PEDOT:PSS. PEDOT:PSS/n-Si solar cells showed a power conversion efficiency (PCE) of 13〜14% (11〜12%) for a 2×2 cm² (4 inch) size device. Solar cell modules consisting of ten units of series-connected 2×2 cm² (4 inch) sized cells, exhibited an output power of 0.37W (7.3W). The junction property at the PEDOT:PSS/n-Si interface was also monitored for varying donor concentrations of n-Si using the current-voltage, capacitance-voltage, Kelvin-probe, and the photoemission yield characterizations. The carrier transport at the PEDOT:PSS/n-Si heterojunction is mainly determined by the diffusion of the minority carrier, which suggests that the PEDOT:PSS/n-Si junction forms a p⁺n-junction.