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 (eta(e)) increased by a factor of 5.13, whereas one with both LiI and tBP added at the optimum concentrations gives an eta(e) 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.