First-Principles Screening and Design of Novel Triphenylamine-Based D−π–A Organic Dyes for Highly Efficient Dye-Sensitized Solar Cells

We screen a series of π-conjugated bridge groups and design a range of metal-free organic donor−π–acceptor (D−π–A) <b>SPL101</b>–<b>SPL108</b> dyes based on the experimentally synthesized <b>C217</b> dye for highly efficient dye-sensitized solar cells (DSSC) using density functional theory (DFT) and time-dependent DFT (TDDFT), and further calculate their physical and electronic properties, including geometrical structures, electronic cloud distribution, molecular orbital energy levels, absorption spectra, light harvesting efficiency (LHE), driving force of injection (Δ<i>G</i>_inj) and regeneration (Δ<i>G</i>_reg), and electron dipole moment (μ_normal). Results reveal that the π-conjugated bridge groups in <b>SPL103</b> and <b>SPL104</b> are promising functional groups for D−π–A organic dyes. In particular,<b> SPL106 </b>and<b> SPL108</b> have not only smaller energy gaps, higher molar extinction coefficients, and 128 and 143 nm redshifts, but also a broader absorption spectrum covering the entire visible range up to the near-IR region of 1200 nm compared to <b>C217</b> dye