Influence of Small Molecules in Conducting Polyaniline on the Photovoltaic Properties of Solid-State Dye-Sensitized Solar Cells

Solid-state dye-sensitized solar cells (DSSCs) were fabricated using 4-dodecylbenzenesulfonic acid-doped polyaniline (PANI−DBSA) blended with LiI and 4-tert-butylpyridine (tBP) as hole conductors. The introduction of LiI and tBP into the polymer improves the photovoltaic behavior of solid-state DSSCs significantly. Compared with a DSSC only using PANI−DBSA as a hole conductor, one with LiI added at the optimum concentration gives an overall solar-to-electric energy conversion efficiency (ηe) increased by a factor of 5.13, whereas one with both LiI and tBP added at the optimum concentrations gives an ηe increased by a factor of 6.6 and a maximum value of the incident photon to current conversion efficiency increased 100%. In addition, the photovoltage and photocurrent transients are determined to investigate the influence of LiI and tBP in PANI−DBSA on the photovoltaic performance of solid-state DSSCs.