| With the recent development of quantum chemistry and theoretical methods, thedeep understanding of the detailed metal-free dyes utilized in dye-sensitized solarcells has been achieved. It has forced researchers to find experimental renewable andclean energy due to the energy crisis in the last two decades, the solar energy becauseof its infinite nature and its environmental friendliness has become the focus ofresearchers in the field of photovoltaic. Various types of organic photosensitive dyeshave been synthesized by experimental researchers around the world to takeadvantage of solar energy, but most synthetic dyes are unsatisfied efficiency whichcould not be explained rationally. Therefore, analyze and explore the unsatisfiedresults deeply via the computational method which contains the quantum chemistrytheory, density functional theory (DFT), time-dependent density functional theory(TD-DFT), natural bond orbital analysis (NBO) and the excited state theory is critical.Based on the optimized molecular structure to simulate the UV-Vis, InfraredSpectroscopy, the NBO population of ground and excited states as well as thereorganization energy could help to shed light on the relationship between themolecular structure and properties. Based on these computed results, it could pave anew way to design new sensitizers.The whole paper consists of five sections.The first section is mainly about the development and application of dye-sensitized solar cells and the common series of sensitizers.The second section summarizes the theory of quantum chemistry and calculationmethods of this paper. The content of the section is the basis of our studies and offerus with useful and reliable quantum methods.The third section focused on the theoretical study on the properties of indolinedyes with D-A-π-A and D-π-A configurations for dye-sensitized solar cells. We haveengaged in a detailed study to elucidate the difference between the D-A-π-A andD-π-A configurations. Calculations indicate that the D-A-π-A could exhibit betterphotophysic properties than the D-π-A architecture.The fourth section concentrated on the molecular engineering of indoline-based D-A-π-A organic sensitizers WS-9towards high efficiency performance from firstprinciples calculations. On the basis of the report of dye WS-9by Tian, Zhu andco-workers, we have engaged in a detailed design and characterization. The sectioninvolves four sides, i.e., introduction, computational methods, results and discussion,conclusion. Based on the dye WS-9reported by Tian and Zhu et al., we have engagedin a detailed design and investigation for new six series dyes. Calculations indicatethat dye CDQ-A1is the best candidate due to it performs nicely on these parametersof the maximum absorption λmax, light harvesting efficiency LHE, adsorbed dipolemoment, and kinetics of electron injection and recombination could achieve a goodbalance and are superior to WS-9. We hope this will be helpful for the design oforganic dye with target properties to improve the performance of DSSCs.The fifth section contains the influence on the performance of DSSCs whichrelated with the dimmers of sensitizers C219, sensitizer and coadsorbent (CDCA) orsolvent. we motivated to investigate the absorption of the dimmers between thedye-dye, dye-solute, and dye-co-adsorbent, respectively, to provide a new sight toconstruct new sensitizers and optimize the conditions which related to the finalconversion efficiency. We use C219as chromophore, CDCA as co-adsorbent,methanol and ethanol as solvent to computed their intramolacular and absorption. Theresults show that all dimmers could present different effect on absorption.All research work in section3-5is that computational investigations on thesedyes have been carried out by the density functional and time-dependent densityfunctional approaches. We wish that the conclusions provided in this thesis could behelpful for the designing of new metal-free organic sensitizers in the future. |
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