Regio(ir)regular naphthalenediimide- and perylenediimide-bithiophene copolymers: How MO localization controls the bandgap
| Autor: | Antonio Facchetti, Johannes Gierschner, Begoña Milián-Medina, Zhihua Chen, Michael Wykes |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Absorption spectroscopy
Organic solar cell Band gap Chemistry 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Acceptor 0104 chemical sciences Materials Chemistry Copolymer Molecular orbital Singlet state Triplet state 0210 nano-technology |
| Zdroj: | Repositorio Institucional del Instituto Madrileño de Estudios Avanzados en Nanociencia instname |
| Popis: | Absorption spectra of regio(ir)regular naphthalenediimide (NDI)- and perylenediimide (PDI)-bithiophene (2T) donor/acceptor (D/A) copolymers are surprisingly similar despite cross-conjugation in the regioirregular structures. This result is traced back to largely localized frontier molecular orbitals (FMOs) as revealed by (time-dependent) DFT calculations. Interestingly, while the FMOs of the P(PDI-2T) copolymer are localized solely in the PDI units, they are predominantly localized in the respective D/A units of the P(NDI-2T) copolymer. The pronounced CT character of the lowest singlet state in P(NDI-2T) should give rise to a close lying CT triplet state, generating small singlet–triplet gaps; this property might be of significant importance for the future design of polymers for organic solar cells with reduced charge recombination rates. |
| Databáze: | OpenAIRE |
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