Syafri Syafri, Fandi Oktasendra, Nurul Widya, Permono Adi Putro, Harman Amir, Husin Alatas, Faozan Ahmad, Aditya Wibawa Sakti
Renewable energy technology plays an important role in tssshe realization of sustainable development objectives, such as those by the United Nations (UN) on Sustainable Development Goals (SDGs). In this regard, the natural dye extracted from Indigofera tinctoria (indigo) is a potential source for low cost and eco-friendly photo-sensitizer which could be used in Dye-Sensitized Solar Cells (DSSCs). In this study, the electronic and optical characteristics of modified indigo derivatives are investigated for utilization in DSSCs using first-principles method. Four donor-indigo-acceptor (D-Indigo-A) architectures were developed by replacing the amine-type donating groups as well as the cyanoanistan acceptor conformations in the indigo scaffold. The DFT/TDDFT calculations at the B3LYP/def2-SVP level in DMF identified that these structure modifications brought about remarkable improvements in the optoelectronic properties, especially for M2. This derivative showed a red shift in absorption peak (518.8 nm), lower HOMO-LUMO energy gap (2.25 eV), high light-harvesting efficiency (74.72%), low exciton binding energy (0.28 eV) and suitable kinetics of electron injection/dye regeneration. These findings demonstrate the potential of these modified indigo derivatives as effective, environmentally friendly and low-cost natural sensitizers that correspond to SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action). © 2026, Walailak University. All rights reserved.
Department of Physics, Universitas Negeri Padang, Padang, 25131, Indonesia; Department of Chemistry, Universitas Negeri Padang, Padang, 25131, Indonesia; Theoretical Physics Division, Department of Physics, IPB University, Kampus IPB Darmaga, Bogor, 16680, Indonesia; Department of Physics, Faculty of Science, Universitas Mandiri, Subang, Indonesia; Indonesia Computational Research Consortium on Renewable Energy, IPB University, Bogor, 16680, Indonesia; Waseda Research Institute for Science and Engineering, Waseda University, Tokyo, 169-8555, Japan
