2020 Fiscal Year Annual Research Report
Elucidation of Stability of NIR Dyes Capable Efficient Photo-conversion by Logical Molecular Design
| Project/Area Number |
18K05300
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
PANDEY SHYAM S. 九州工業大学, 大学院生命体工学研究科, 准教授 (60457455)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | Structure optimization / TD-DFT calculations / Dye sensitizers / Squaraine dyes / Anchoring group / Adsorption behaviour / Binding strength / DSSC |
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| Outline of Annual Research Achievements |
Combined theoretical based on quantum chemical (QC) calculations and experimental approaches have been used for designing a series of NIR dyes with varying anchoring groups aiming towards improved stability and photoconversion efficiency (PCE). Our results indicated only 60-70 nm (0.06 eV) in λmax and (±0.06 eV) in Eg difference between theoretical prediction and experiment results of newly designed dyes. Inspired from the experimental determination of the energy band gap (Eg), a new method to construct the theoretical energy band diagram based on QC calculations. Amongst newly designed NIR dyes, ten potential candidates were successfully synthesized and their experimental energy band diagram matches very well with that of the theoretically calculated counterparts having error of only ± 0.06 eV. Nature of the anchoring group of the newly designed dyes on their adsorption behaviour and binding strength on TiO2 along with PCE was also systematically investigated. Phosphonic acid and cyanoacrylic acid anchoring groups were demonstarted to exhibit contrasting opposite behaviour in terms of binding strength and PCE. In terms of the PCE and stability acrylic acid group was found to be optimum. A perusal of the binding strength corroborated that SQ-162 bearing double anchoring groups of phosphonic and acrylic acid exhibited >550 times stronger binding as compared to dye SQ-140 having cyanoacrylic anchoring group, while keeping appreciably good PCE as compared to the dye with only phosphonic acid group.
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