Photoactuated properties of acetylene-congeners non-metallic dyes and molecular design for solar cells

This paper theoretically simulated (using DFT and TD-DFT in N,N-dimethylformamide (DMF) solvent) the photodynamic properties of three non-metallic dye molecules with D-π-A₁-π- A₂ structure. The total photoelectric conversion efficiency (PCE) could be evaluated by the following parameters: the geometric structures, the electronic structures, and the absorption spectra, the analyses of charge difference density (CDD) and natural bond orbitals (NBO), the analyses of ionization potential (IP) and electron affinity (EA) from electronic contribution capacity, the reorganization energies (λ_h, λ_e, and λ_total), and the chemical reaction parameter (h, ω, ω^-, and ω⁺) for intramolecular charge transfer (ICT) processing, the excited lifetime (τ) and the vertical dipole moment (μ_normal). The ΔG^inject, the ΔG_dye ^regen, the light harvesting efficiencies (LHE) and the excited lifetime (τ) were used to explain experimental J_sc. The experimental trend of V_oc was explained by the calculation of ΔE_CBand μ_normal. Moreover, the 15 dyes were designed by adding the electron-donor groups (-OH, -NH₂, and -OCH₃) and the electron-acceptor groups (-CF₃, -F, and -CN) to the LS-387 molecular skeleton, which improved electronic contribution, intramolecular charge transfer (ICT), and optoelectronic performance.