Computational Study on D-π-A-Based Metal-Free Donor-Tuned Molecules for Efficient Organic Dye-Sensitized Solar Cells

Abstract

In this paper, newly metal-free four donor-[Formula: see text]-acceptor (D-[Formula: see text]-A) molecules (C1D1–C1D4) were designed and used for dye-sensitized solar cells (DSSCs) application, based on literature C1-1. Tetrahydroquinoline, thiophene, and 2-cyanoacrylic acid act as the electron-D, spacer, and electron-A/anchoring groups for all dyes, respectively, while the donor part was tuned and the effect was examined. The density functional theory (DFT) and time-dependent DFT (TD-DFT) have been used on the electronic transitions, geometric structures, absorption properties, electron injection ([Formula: see text]), dye regeneration ([Formula: see text]), light harvesting efficiency (LHE), ground and excited states of dipole moments ([Formula: see text]), open-circuit photovoltage ([Formula: see text]), molecular electrostatic potential (MEP) and Mulliken population analysis (MPA) of the dyes. The TD-DFT method using different functionals with exchange-correlational (XC) and long-range correlated (LC) was calculated to obtain literature data. The computational outcomes have displayed that the Coulomb-attenuating method (CAM-B3LYP) in conjunction with a 6-31G(d,p) basis set was proficient in calculating the UV-Vis spectra of the molecules. The frontier molecular orbitals’ (FMOs) contribution of the HOMOs and LUMOs of C1D1-C1D4 molecules can be confirming positive consequences on the regeneration and electron injection processes. In particular, C1D4 (N(CH3)2) molecule shows a smaller energy gap ([Formula: see text]), longer wavelength, high [Formula: see text] and [Formula: see text]. To conclude, these outcomes display that the calculated C1D1–C1D4 molecules are capable applicants to deliver better performance of the DSSCs.