High photovoltaic performance (23.75) of triazatruxene-based dye-sensitized solar cells containing different π bridges: computational investigation

Abstract

Inspired by the reference R with the IUPAC name ((Z)-2-(aminomethyl)-3-(5-((3-methyl-5-(7-(4-methyl-5-(5,10,15-trimethyl-10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazol-3-yl)thiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)thiophen-2-yl)ethynyl)furan-2-yl)acrylic acid)), six new organic (D–π–A) dyes for dye-sensitized solar cell (DSSC) applications have been designed. The designed molecules have an electron donor (D), triazatruxene, connected through different π-bridges and an electron acceptor (A), 2-cyanoacrylic acid. The key parameters of the optoelectronic and photoelectric performances were computed by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Compared to the original dye R, the designed compounds have a higher light harvesting ability with an absorption spectrum that appeared around the infrared region. The maximum absorption wavelength shifted to red from 78 nm to 148 nm, and the light-harvesting efficiency (LHE) curve broadened in the visible region and excellent electron injection efficiency was observed. All these contribute to better short-circuit current density (J_SC) and power conversion efficiency (PCE). The results obtained through the global evaluation model for the reference dye R were J_SC = 19.21 mA cm⁻², V_OC = 0.838 V, and PCE = 13.92%. These values are closer to the experimental results (J_SC = 19.74 mA cm⁻², V_OC = 0.957 V, and PCE = 13.4%). The Tat-2 dye achieved a PCE of 23.75%. Therefore, it can be considered a candidate dye for high-yield DSSCs.