Structure dependence in hybrid Si nanowire/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) solar cells: Understanding photovoltaic conversion in nanowire radial junctions

Hybrid Si/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solar cells based on nanowire array structures with radial and axial junctions are prepared and investigated. Compared to axial junction cells, radial junction cells exhibit much higher external quantum efficiency for long wavelength light due to improved separation of photogenerated charge carriers, resulting in more than 10 times higher power conversion efficiency (PCE). By tuning the height of nanowire array for the hybrid radial junction cells and investigating the external quantum efficiency and open circuit voltage decay, we identify that inefficient carrier collection due to interfacial recombination is the major limiting factor for the hybrid radial junction cell performance.