Prediction of Power Conversion Efficiencies of Diphenylthienylamine-Based Dyes Adsorbed on the Titanium Dioxide Nanotube.

The power conversion efficiency (η) is the most important key to determine the efficiency of dye-sensitized solar cell (DSSC) devices. However, the calculation of η theoretically is a challenging issue since it depends on a large number of experimental and theoretical parameters with extensive related data. In this work, η was successfully predicted using the improved normal model with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) for eight diphenylthienylamine-based (DP-based) dyes with various π-bridge adsorbed on titanium dioxide. The titanium dioxide is represented by a nanotube surface (TiONT); this surface is rarely investigated in the literature. The π-linker consists of five (DP1)- or six (DP2)-membered rings and contains none to three nitrogen atoms (D0-D3). The reliability of the estimated values was confirmed by the excellent agreement with those available for the two experimentally tested ones (DP2-D0 and DP2-D2). The deviations between the experimental and estimated values were in the ranges of 0.03 to 0.06 mA cm, 0.05 to 0.3 mV, and 0.37 to 0.18% for short-circuits current density ( ), open-circuit voltage ( ), power conversion efficiency (%η), respectively. More importantly, the results revealed that using pyridine (DP2-D1), pyrimidine (DP2-D2), and 1,2,4-triazine (DP2-D3) improves the power conversion efficiencies in the range of 6.03 to 6.90%. However, the cyclopenta-1,3-diene (DP1-D0) shows superior performance with a predicted η value that reaches 9.55%.