Computational analysis on D–π–A based perylene organic efficient sensitizer in dye-sensitized solar cells

We designed and screened a series of metal-free organic dyes with different tunable donors (D1–D3) based on literature dye (3a). The D1–D3 organic dyes have been applied in dye-sensitized solar cells (DSSCs). Triphenylamine, thiophene and 2-cyanoacrylic acid groups as an electron donor (D), spacer (π) and electron acceptor (A), respectively, to form a D–π–A system. Density functional theory (DFT) and time-dependent DFT was employed to study the electronic charge distribution, intramolecular charge transfer, absorption spectra and photovoltaic (PV) parameters of the dyes. PV presentation of the dye molecules depends on tunable donors (D1–D3) classification. Results reveal that the replacing group of D3 dye has been red-shift absorption spectra and improves PV cell performance. Particularly, D2 and D3 dyes have smaller energy gaps and higher absorption spectra covering entire visible region, compared to D1 dye. Therefore, these results display that molecular tailoring is a promising scheme to improve D–π–A design of sensitizer for highly efficient DSSCs application.