Electrical characterization of inorganic-organic hybrid photovoltaic devices based on silicon-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)

Hybrid organic-inorganic photovoltaic devices based on nanostructured silicon and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hybrid devices present excellent light harvesting capabilities as well as a simple fabrication process. Unlike the metal/Si junction, PEDOT:PSS solution can be solution-casted onto the silicon surface structure to build up hybrid photovoltaic devices without using vacuum deposition techniques. Detailed electronic characterization at PEDOT:PSS/Si heterojunctions is indispensable for achieving a high-performance device. In this paper, the electronic properties of current-voltage, capacitance-voltage, and internal quantum efficiency are characterized in order to explore the organic-inorganic heterojunctions properties. The interfacial defect state density (D_it) of hybrid organic-inorganic photovoltaic devices as well as majority carrier charge transfer velocity (v_n) has been extracted from the electrical measurement results. It has been found that less D_it and lower v_n can lead to improved electric output characteristics of the organic-inorganic heterojunctions photovoltaic devices, which is ascribed to suppressed charge recombination at the organic-inorganic interface.