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Lawsone isomers, lawsone ether and bilawsone for dye-sensitized solar cells applications: DFT and UV–Vis studies
摘要： Structural and optoelectronic properties of lawsone (L), lawsone ether (LE) and bilawsone (BL) were studied theoretically using the DFT and time-dependent DFT methods with hybrid functional B3LYP5 and 6-311G (2d,p) basis set. For the monomer lawsone molecule, isomerization reaction between two rotational isomers was analyzed based on a thermodynamic approach. The electronic spectra of the dyes molecules in a vacuum and solvents (DMSO and CH2Cl2) were computed. The maximum wavelengths were found at 355e408 nm for the LE and 350e448 nm for BL that indicated bands shift to visible range compared to L (340 nm). The UVeVis spectra of the L and BL were measured experimentally in DMSO solution. For the BL, a broad and intensive band was observed in a visible region at 452 nm that apparently would favour sensitizing ability of the dye. The optoelectronic properties of the LE and BL showed them as more promising candidates for DSSCs applications compared to the individual lawsone dye.
关键词： Lawsone ether,Dye-sensitized solar cells,Lawsone isomers,DFT/TD-DFT,Bilawsone,UVeVis/vibrational spectra
更新于2025-09-19 17:13:59
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Performance Enhancement of Betanin Solar Cells Co-Sensitized with Indigo and Lawsone: A Comparative Study
摘要： Co-sensitization is an important strategy toward e?ciency enhancement of solar cells by enabling better light harvesting across the solar spectrum. Betanin is a natural dye which absorbs light in the major portion of the incident solar spectrum (green region) and is the most e?cient natural pigment used in dye-sensitized solar cells. This study investigates the performance enhancement of a betanin solar cell by co-sensitizing it with two natural pigments which show complementary light absorption, indigo and lawsone, absorbing in the red and blue regions of the solar spectrum, respectively. The calculated highest occupied molecular orbital and lowest unoccupied molecular orbital energies of the pigment molecules, derived from density functional theory (DFT) simulations, con?rmed their optimal alignment with respect to the conduction band energy of the TiO2 semiconductor and reduction potential energy level of the I?/I3 ? electrolyte, a necessary requirement for optimal device performance. Lawsone solar cells displayed better performance, showing average e?ciencies of 0.311 ± 0.034%, compared to indigo solar cells showing e?ciencies of 0.060 ± 0.004%. Betanin was co-sensitized with indigo and lawsone, and the performances of the co-sensitized solar cells were compared. The betanin/lawsone co-sensitized solar cell showed a higher average e?ciency of 0.793 ± 0.021% compared to 0.655 ± 0.019% obtained for the betanin/indigo co-sensitized solar cell. An 11.7% enhancement in e?ciency (with respect to betanin) was observed for the betanin/indigo solar cell, whereas a higher enhancement of 25.5% was observed for the betanin/lawsone solar cell. Electrochemical impedance spectroscopy studies con?rmed that the higher e?ciency can be attributed to the higher electron lifetime of 313.8 ms in the betanin/lawsone co-sensitized solar cell compared to 291.4 ms in the betanin/indigo solar cell. This is due to the energy levels being more optimally aligned in lawsone compared to that of indigo, as observed in the DFT studies, and the lack of dipole moment in indigo, resulting in more e?cient charge separation and charge transfer in lawsone.
关键词： DFT simulations,indigo,electrochemical impedance spectroscopy,dye-sensitized solar cells,co-sensitization,betanin,lawsone
更新于2025-09-12 10:27:22