Efficient organic-inorganic hybrid Schottky solar cell: The role of built-in potential

The organic-inorganic hybrid Schottky solar cells based on solution processed poly(3,4-ethlenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in combination with silicon offer the merits of simple fabrication process and potential low cost. Here, we demonstrate that the work function (WF) of PEDOT:PSS films plays a critical role on the electronic output characteristics of the device. The WF of PEDOT:PSS is tuned by adding an aqueous solution of perfluorinated ionomer (PFI) due to its high electron affinity, which is compatible to fabricate the hybrid Si/PEDOT:PSS device. With an addition of 4% (weight) PFI into PEDOT:PSS, the device achieves a fill factor (FF) as high as 0.70 without sacrifice of open-circuit voltage and short-circuit current density, which improves 20% in comparison with the pristine PEDOT:PSS (0.58). The detailed electrical output measurements reveal that the high FF is ascribed to the enhanced built-in potential as well as suppression of charge recombination at organic-inorganic interface.