LAUSR

Polymer/Si hybrid solar cells (HSCs) are promising for mass production because of their high performance and low cost, but several problems such as big reflective index of Si, low aperture ratio of the mesa-type metal transparent conductive electrodes (TCEs), and large recombination loss at Si rear contact should be solved for the practical applications. Here, we first report a HSC structure of multilayer graphene TCE/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/Si nanowires/n-Si/TiOx (back surface passivation layer) to cope with aforementioned problems. Resulting maximum power conversion efficiency (PCE) is 12.10%, much larger than that of the planar-Si-type HSC (10.11%) as a control sample, mainly due to the lowered reflectance (increased absorption) and recombination loss. As the active area increases from 14 to 50 mm2, the PCE decreases by only 2.5% from 12.10 to 9.60%, possibly resulting from the area-dependent change in the uniformity of the Si NWs. The PCE shows only a 10% decrease for 3...