PEDOT:PSS as an alternative hole selective contact for ITO-free hybrid crystalline silicon solar cell

Abstract

Organic-inorganic hybrid solar cells were fabricated by spin coating of conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as hole selective contact upon textured n-type crystalline silicon wafers. Two different PEDOT:PSS commercial products (Clevios HTL Solar and PH1000) were compared, enhancing their conductivity and wettability by addition of dimethyl sulfoxide cosolvent and Capstone FS-31 surfactant. Transmission line measurements (TLM) revealed that the sheet resistance of the PEDOT:PSS layer was comparable with that of conventional Indium-Tin oxide (ITO) electrodes, allowing its use as a conductive transparent layer in an ITO-free solar cell. Quasi-steady-state photoconductance measurements revealed an implied open-circuit voltage of 644 mV for HTL Solar, which is equivalent to a saturation current density of 255 fA/cm2. In general, the performance of HTL Solar was better than PH1000, exhibiting power conversion efficiency (1 × 1 cm2 cell area) of 11.6%, as compared with 8.5%.