Theoretical calculation of the influence of internal acceptor on photovoltaic performances in triphenylamine-based dyes for dye-sensitized solar cells

Novel series of D-A(2)-pi-A1 metal-free organic dyes are taken into consideration to investigate the influence of different internal acceptors on their efficiency in dye sensitized solar cells (DSSCs), these dyes are designed based on C218 reference dye. The crucial parameters affecting open circuit photovoltage (V-OC) and short circuit current density (J(SC)), as well as light harvesting efficiency (LHE), driving force of regeneration (Delta G(reg)), electronic injection driving force (Delta G(inj)), vertical dipole moment (mu(norm)), electron reorganization energy (lambda(e)), hole reorganization energy (lambda(h)), ionization potential (IP), electron affinity (EA), chemical hardness (h), electrophilicity (omega), electroaccepting power (omega(+)), and the conduction band shift (Delta E-CB) are theoretically investigated in detail using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. The results indicate that the insertion of internal acceptor between donor and pi-bridge moieties leads to red-shifted for the UV-vis absorption spectra and improves the photovoltaic properties. Thus, this study is expected to provide a theoretical basis for proper design and structural modifications in the development of dyes in dye-sensitized solar cells (DSSCs).