Theoretical investigations on newly designed triphenylamine-based donors applied into the D–π–A and D–A–π–A type sensitizers

Abstract

Three organic electron donors (T1, T2 and T3) were creatively synthesized by researchers, based on their extraordinary characteristics under the experimental conditions. The three original donors were selected and designed to substitute the primary donors of two dye molecules of different types LJ1 (D–π–A) and WS4 (D–A–π–A). In the subsequent theoretical investigations, density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to explore and simulate the fundamental parameters for these six potential sensitizers in dye-sensitized solar cells (DSSCs). For the essential parameters in evaluating the energy conversion process, such as oscillator strength (f) and light harvesting efficiency (LHE), the driving force of electron injection (ΔGinject) vertical dipole moments (μnormal) and driving force of regeneration (ΔGregen) were simulated. In addition, energy levels and the orbital compositions, absorption spectra, natural bond orbital (NBO) analysis from S0 to S1, distance between hole and electron centroid (DCT), average hole-electron distance (Δr) upon photoexcitation, overlap distance of hole and electron (S), transferred charge (ΔQ) for intramolecular charge transfer (ICT) processing, excited lifetime and electron injection lifetime of the six chromophores were systematically computed. Because of the different configurations formed in the donor motif, the correlative properties of the six newly designed sensitizers compared with prototype sensitizers of LJ1 and WS4 were altered and promoted significantly.