Molecular Screening of Different p-Linker-Based Organic Dyes for Optoelectronic Applications: Quantum Chemical Study

In this work, metal-free organic dyes (SZ-1-SZ-5) based on phenothiazine (PTZ) as donor (D) unit and different p-conjugated (p) as spacers and acceptors (A) representing cyanoacetic acid (D-p-A) have been investigated to examine their optoelectronic properties by density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. A favourable electron transfer into the semiconducting material (TiO2) is effectively obtained by the optimized ground state HOMO-LUMO energy values of the SZ-3 molecule. The photovoltaic (PV) parameters of the oxidation and reduction potential energies (E-dye and Edye*), a driving force of electron injection (Delta G (inject)), dye regeneration (Delta G (reg)), light-harvesting efficiency (LHE), dipole moment ( mu (normal)), short-circuit current density ( J (SC)) and open-circuit photovoltage ( eV (OC)) were obtained and are discussed in detail. On the other hand, the TD-DFT approach was used to calculate and describe the optical properties of all SZ-1-SZ-5 molecules in terms of absorption energy associated with maximum wavelengths ( lambda (max)), emission spectra ( lambda (emi)), oscillator strengths (f) and excitation energies (E). Finally, the theoretical findings represent the various p-spacers in the optoelectronic capabilities of the D-p-A-based dye derivative materials, and they offer useful guidelines for future structures designed for solar cell applications.

Automated summary

In this study, the optoelectronic properties of metal-free organic dyes (SZ-1-SZ-5) based on phenothiazine (PTZ) as the donor unit and different p-conjugated spacers and acceptors were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The optimized ground state HOMO-LUMO energy values of the SZ-3 molecule demonstrated favorable electron transfer into the semiconducting material (TiO2). Photovoltaic parameters and optical properties of the SZ-1-SZ-5 molecules were obtained and discussed in detail, providing useful guidelines for future structures designed for solar cell applications.