Theoretical investigation of the nitrogen-heterocyclic as π-linker in diphenylthienylamine-based dyes adsorbed on TiO2 nanotubes for DSSCs applications

Abstract

A planer π-conjugated spacer is one of the strategies used to develop the performance of the dye-sensitized solar cell (DSSC). This study focuses on describing the effect of the nitrogen-based heterocycles as π-linker on the properties of novel photosensitizers based on diphenylthienylamine (DPTA). The π-linker is five- (5M), or six-membered rings (6M) contains none (D0), one (D1), two (D2), and three (D3) nitrogen atoms. The geometrical structures, electronic properties, and photovoltaic parameters are calculated using the DFT/B3LYP and TD-DFT/CAM-B3LYP functional with 6-31G+(d,p) basis set. As well, the polarised continuum model (PCM) is used to simulate the solvation effects. To understand the mechanism of electrons injection to semiconductor, the adsorbed dyes on titanium dioxide nanotube (TiO2NT) are studied, using B3LYP/6-31G(d) and LANL2DZ basis sets. The results revealed that 6M is better than 5M dyes due to the extended conjugation in the 6M dyes. As well, the 5M-D0 (cyclopenta-1,3-diene) shows a broad absorption band from 400 to 850 nm at the near-infrared (NIR) region with an absorption wavelength of 561.24 nm. Besides, 5M-D0, 6M-D3 (1,2,4-triazine) can be considered promising photosensitizers due to their unique electronic properties that will be expected to improve the power conversion efficiency of the DSSC device.