Computational investigation of dyes-sensitized solar cells containing various π-bridges achieving high photovoltaic performance with triazatruxene-based dyes

[Display omitted] •Five-membered rings in the π-bridge, such as 5,5-Dimethylcyclopentadiene (TAT-C), furan (TAT-O), and 1,1-dimethyl-1H-silole (TAT-Si), were investigated by DFT and TD-DFT.•Geometry, electrical structure, intramolecular charge transfer, reorganization energy, light-harvesting efficiency, and other microscopic factors were examined.•The power conversion efficiency estimated for the TAT-C dye is 27.23%, followed by the dye TAT-O (25.80%), and finally, the TAT-Si (24.12%). In this work, three organic triazatruxene-based dyes, containing cyanoacrylic acid as acceptor and different five-membered rings in the π-bridge, such as 5,5-Dimethylcyclopentadiene for TAT-C, furan for TAT-O and 1,1-dimethyl-1H-silole for TAT-Si, were theoretically investigated by density functional theory (DFT) and time-dependent (TD-DFT) for application in dye-sensitized solar cells (DSSCs). Geometry, electrical structure, intramolecular charge transfer (ICT), reorganization energy, light-harvesting efficiency (LHE), and other microscopic factors were examined to determine how the π-bridges affected short-circuit current (JSC) and open circuit voltage (VOC). Our theoretical findings show that dye TAT-C exhibits remarkably better light-harvesting ability in the near-infrared region, with a broader LHE curve and a greater JSC. In parallel, all three dyes have a fast interfacial electron transfer (IET) rate. Furthermore, based on the overall evaluation model, we estimate the power conversion efficiency (PCE) for the TAT-C dye is 27.23 % (JSC = 37.30 mA.cm-2, VOC=0.838 V), followed by the dye TAT-O (PCE = 25.80 %, JSC=34.19 mA.cm-2, VOC= 0.868 V), and finally, the TAT-Si (PCE = 24.12 %, JSC=30.80 mA.cm-2, VOC= 0.898 V). Consequently, the principal objective of this investigation is to contribute a theoretical framework for creating and making novel organic dyes for promising DSSC applications.