Identification of novel indole-based dyes as active photo-sensitizers: Synthesis, photophysical, electrochemical and computational investigation

• Published in: Optical materials Vol. 145; p. 114391
• Main Authors: Roys, Krupa Elsa, S L, Manju
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2023
• Subjects: Density functional theory (DFT); Electrochemical; Indole; Light-harvesting efficiency (LHE); Molecular electrostatic potential; Time-dependent density functional theory (TD-DFT); Time-dependent density functional theory (TD-DFT); Molecular electrostatic potential; Indole; Density functional theory (DFT); Electrochemical; Light-harvesting efficiency (LHE)
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2023.114391

Novel D–π–A type indole-based compounds have been designed and synthesized as active photosensitizers for dye-sensitized solar cells (DSSCs). The molecular structures of indole-based compounds were identified and characterized using IR, NMR, and HRMS spectra data. The attributes of the indole-based compounds were evaluated in terms of their optical, electrochemical, light-harvesting efficiency (LHE), HOMO/LUMO level and redox behaviour. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were conducted to disclose the electronic and optical attributes of novel indole-based compounds. All the compounds revealed well-defined absorption with elevated absorptivity and a small band gap (2.89–3.01 eV). The HOMO to LUMO energy transfer percentage obtained from TD-DFT, for the synthesized compounds is in the range of 86%–99%. The projected light-harvesting efficiency (LHE) for the indole-based compounds is between 0.371 and 0.666. The greatest open circuit voltage (Voc) value was found in the methoxyphenyl-substituted indole-based compound, which is advantageous for DSSCs to obtain external maximum power output. As active photosensitizers for dye-sensitized solar cells (DSSCs), novel D–π–A type indole-based compounds have been developed and synthesized. The optical, electrochemical, light-harvesting efficiency (LHE), HOMO/LUMO level, and redox behaviour of the new compounds were examined. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were used to reveal the electrical and optical properties of new indole-based molecules. All of the compounds demonstrated well-defined absorption with high absorptivity and a narrow band gap (3.13–3.25 eV). For the synthesized molecules, the HOMO to LUMO energy transfer percentage achieved using TD-DFT ranges from 86% to 99%. The LHE of indole-based compounds is expected to be between 0.371 and 0.666. [Display omitted] •Novel D–π–A type indole-based compounds have been designed and synthesized for dye-sensitized solar cells (DSSCs).•The properties of the synthesized compounds were assessed in terms of their optical and electrochemical behaviour. DFT and TD-DFT were conducted to disclose the electronic and optical properties of synthesized compounds.•All the compounds revealed well-defined absorption with high absorptivity and low band gap (3.13–3.25 eV).•The HOMO to LUMO energy transfer percentage obtained from TD-DFT, for the synthesized compounds is in the range of 86%–99%.•The projected light-harvesting efficiency (LHE) for the indole-based compounds is between 0.371 and 0.666.