Abstract
In this work, the newly designed phenothiazine-based organic dye (PT-BTBA, PT-EBTBA, and PT-EBTEBA) derivatives were screened and investigated for dye-sensitized solar cell (DSSC) application. The literature dye of SB covers the electron-donor (D) in phenothiazine and cyanoacrylic acid in electron-acceptor (A) based on D-A structure. In order to improve the pi-conjugation and acceptor group effects on the SB dye were theoretically investigated. The effect of D-pi-A designed dyes on the optical absorption spectra and photovoltaic (PV) parameters was implemented by the density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. Also, the hybrid functionals were initially evaluated to establish an accurate methodology for calculating the first-singlet absorption peak of SB dye. Consequently, TD-CAM-B3LYP functional and 6-311++G(d,p) theory were well matched with the literature data. According to this result, phenothiazine-4-((7-ethynylbenzo[c][1,2,5]thiadiazol-4-yl)ethynyl)benzoic acid (PT-EBTEBA) dye has the strong group for more red-shifted and successful electron injected into the conduction band edge of TiO2 surface. It is expected to provide some theoretical guidance on designing photosensitive with new metal-free organic dyes for use in DSSCs yielding highly efficient performance.