Hybrid Ag Nanowire–ITO as Transparent Conductive Electrode for Pure Sulfide Kesterite Cu2ZnSnS4 Solar Cells

5 years ago

Hybrid Ag Nanowire–ITO as Transparent Conductive Electrode for Pure Sulfide Kesterite Cu2ZnSnS4 Solar Cells

Martin Green, Fangyang Liu, Zi Ouyang, Heng Sun, Kaiwen Sun, Xiaojing Hao, Jongsung Park, Chang Yan

We present the hybrid silver nanowire network–ultrathin ITO as the transparent conductive electrode for earth-abundant and environmentally friendly pure sulfide Cu₂ZnSnS₄ solar cells, replacing the scarce and expensive ITO. For this new hybrid transparent electrode, sputtered intrinsic zinc oxide is introduced as an antireflective coating replacing MgF₂ in traditional Cu₂ZnSnS₄ solar cells. Random arrays of silver nanowire network with different densities hybridized with 20 nm ITO layer are employed in Cu₂ZnSnS₄ devices and their device performance is compared with the reference device with conventional ITO electrode. The devices with the hybrid electrodes with similar sheet resistance to ITO show generally improved current density due to their better optical transparency than ITO while maintaining similar fill factor. Cu₂ZnSnS₄ devices with low density Ag nanowire hybrid electrode give the highest efficiency of 6.4% on average mainly due to improved current density, among which the highest efficiency value is 6.72%. Here, 20 nm intrinsic zinc oxide is selected as an antireflective coating based on optical FDTD simulations, which gives an additional 5% increase in current density and efficiency. A Cu₂ZnSnS₄ device with the low density hybrid electrode is improved from 6.72 to 6.84% after introducing an intrinsic zinc oxide antireflective coating layer.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b05776

DOI: 10.1021/acs.jpcc.7b05776