College of Science, China University of Petroleum, Qingdao, Shandong 266580, PR China; Key Laboratory of New Energy Physics and Materials in University of Shandong, China University of Petroleum, Qingdao, Shandong 266580, PR China.
College of Science, China University of Petroleum, Qingdao, Shandong 266580, PR China; Key Laboratory of New Energy Physics and Materials in University of Shandong, China University of Petroleum, Qingdao, Shandong 266580, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Apr 5;212:272-280. doi: 10.1016/j.saa.2019.01.002. Epub 2019 Jan 3.
Five novel T shaped phenothiazine-based organic dyes DTTP1~5 with different spacers at N (10) position were designed. The geometries, electronic structures, absorption spectra, electron transfer and injection properties of these isolated dyes and dye/(TiO) systems were investigated via density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculation. The optimized geometries indicate that these T shaped dyes show non-planar conformations, which are helpful in suppressing the close intermolecular π-π aggregation in device and enhancing thermal stability. The calculated results indicate that type of π-conjugated spacers can affect the molecular absorption spectra. Introduction of thiophene-benzothiadizole-thiophene unit as π-conjugated spacer can most effectively shift the light absorption to near infrared region and enhance the light harvesting efficiency (LHE). Moreover, it is found that these dyes show a good performance of electron injection and dye regeneration owing to the proper electron injection driving force (ΔG) and dye regeneration driving force (ΔG). The theoretical results reveal that these dyes could be used as potential sensitizers for DSSCs, and DTTP4 would be the most plausible sensitizer for high-efficiency DSSCs due to the narrow HOMO-LUMO energy gap (Δ), broad absorption spectrum, high LHE value, and large dipole moment (μ).
设计了 5 种新型 T 型吩噻嗪基有机染料 DTTP1~5，它们在 N（10）位具有不同的间隔基。通过密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）计算，研究了这些分离染料和染料/（TiO）体系的几何形状、电子结构、吸收光谱、电子转移和注入特性。优化的几何形状表明，这些 T 型染料呈现非平面构象，这有助于抑制器件中紧密的分子间π-π聚集，提高热稳定性。计算结果表明，π-共轭间隔基的类型可以影响分子吸收光谱。将噻吩-苯并噻二唑-噻吩单元作为π-共轭间隔基引入可以最有效地将光吸收转移到近红外区域，并提高光捕获效率（LHE）。此外，还发现由于适当的电子注入驱动力（ΔG）和染料再生驱动力（ΔG），这些染料表现出良好的电子注入和染料再生性能。理论结果表明，这些染料可作为 DSSC 的潜在敏化剂，由于 HOMO-LUMO 能隙（Δ）较窄、吸收光谱较宽、LHE 值较高和偶极矩（μ）较大，DTTP4 可能是高效 DSSC 最合理的敏化剂。
