First-Principle Determination of Electronic Coupling and Prediction of Charge Recombination Rates in Dye-Sensitized Solar Cells

详细信息    查看全文

• 作者：Hsien-Hsin ChouChou-Hsun Yang ; Jiann T’suen Lin ; Chao-Ping Hsu
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：121
• 期：2
• 页码：983-992
• 全文大小：692K
• ISSN：1932-7455

文摘

In the study of dye-sensitized solar cells (DSCs), developing computational predictions of key properties of the dyes is highly desirable for identifying promising candidates. In this work, we report first-principle-based, theoretically estimated charge-recombination (CR) rates from TiO₂ to the cationic dye for 2 pairs of organic dye molecules. A recently developed multistate fragment charge difference (msFCD) scheme, together with long-range-corrected time-dependent density functional theory, was used to calculate the electronic coupling. The msFCD scheme removes the local excitation components in the charge-transfer states, and generates acceptable diabatic states. The range-separated ωPBE and BNL functionals were useful for the charge-transfer problem, and results were largely independent of TiO₂–dye binding modes. The rates obtained for CR to oxidized dye (CRD) followed a trend similar to experimental results. In general, a difference in the reorganization energy (λ) and the free energy (ΔG⁰) had a large effect on electron transfer rates. However, electronic coupling strength could also have a dominant role over (λ+ΔG⁰) in the CRD rate. We report a generally applicable ab initio approach to predict CRD rate and explored the potential roles of coupling factors in the performance of DSCs.