Effect of TiO_2 Microstructure and Introduction of Silver Nanoparticles on Conversion Efficiency of Sb_2S_3 Sensitized Semiconductor Solar Cells

摘要

Sensitized semiconductor solar cells consisting of alternative heterojunction materials (TiO_2/Sb_2S_3/CuSCN) are characterized by an extremely thin absorber that allows effective charge transportation due to reduction in recombination. In these cells, Sb_2S_3 exhibited both positive and negative effects; it generated photocarriers and protected the cell from leakage current, but also behaved as a recombination center and increased the ohmic resistance. CuSCN was the additional critical factor of a cell performance with porous TiO_2. CuSCN deposited on top of the porous structure exhibited two effects: high ohmic resistance and control of effective Sb_2S_3 at pn junctions. To achieve maximization of photocarrier generation and minimization of recombination, silver nanoparticles, which express localized surface plasmons when illuminated, were then applied to Sb_2S_3 cells with compact TiO_2. The results revealed improved photoabsorption without having to increase the amount of Sb_2S_3, and revealed an improved Jsc from 0.66 mA/cm~2 to 1.88 mA/cm~2.