Impact of terminal substituents on the electronic, vibrational and optical properties of thiophene-phenylene co-oligomers

Impact of terminal substituents on the electronic, vibrational and optical properties of thiophene-phenylene co-oligomers Full article

Journal

Physical Chemistry Chemical Physics
ISSN: 1463-9076 , E-ISSN: 1463-9084

Output data

Year: 2019, Volume: 21, Number: 22, Pages: 11578-11588 Pages count : 11 DOI: 10.1039/c9cp00910h

Authors

Sosorev Andrey Yu. ^1,2,3 , Nuraliev Muzaffar K. ^1,2 , Feldman Elizaveta V. ^1,2 , Maslennikov Dmitry R. ^1,2,3 , Borshchev Oleg V. ⁴ , Skorotetcky Maxim S. ⁴ , Surin Nikolay M. ⁴ , Kazantsev Maxim S. ^5,6 , Ponomarenko Sergei A. ^4,7 , Paraschuk Dmitry Yu. ^1,2

Affiliations

1	(Данные Web of science) Lomonosov Moscow State Univ, Fac Phys, Leninskie Gory 1-62, Moscow 119991, Russia
2	(Данные Web of science) Lomonosov Moscow State Univ, Ctr Int Laser, Leninskie Gory 1-62, Moscow 119991, Russia
3	(Данные Web of science) Russian Acad Sci, Inst Spect, Fizicheskaya 5, Moscow 108840, Russia
4	(Данные Web of science) Russian Acad Sci, Enikolopov Inst Synthet Polymer Mat, Profsoyuznaya 70, Moscow 117393, Russia
5	(Данные Web of science) NN Vorozhtsov Novosibirsk Inst Organ Chem, Lavrentieva 9, Novosibirsk 630090, Russia
6	(Данные Web of science) Novosibirsk State Univ, Pirogova 2, Novosibirsk 630090, Russia
7	(Данные Web of science) Lomonosov Moscow State Univ, Dept Chem, Leninskie Gory 1-3, Moscow 119991, Russia

Owing to the combination of efficient charge transport and bright luminescence, thiophene-phenylene co-oligomers (TPCOs) are promising materials for organic light-emitting devices such as diodes, transistors and lasers. The synthetic flexibility of TPCOs enables facile tuning of their properties. In this study, we address the effect of various electron-donating and electron-withdrawing symmetric terminal substituents (fluorine, methyl, trifluoromethyl, methoxy, tert-butyl, and trimethylsilyl) on frontier orbitals, charge distribution, static polarizabilities, molecular vibrations, bandgaps and photoluminescence quantum yields of 5,5'diphenyl-2,2'-bithiophene (PTTP). By combining DFT calculations with cyclic voltammetry and absorption, photoluminescence, and Raman spectroscopies, we show that symmetric terminal substitution tunes the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies of TPCOs within a range of similar to 0.7 eV, shifts the frequencies of the vibrational modes associated with the phenyl rings, changes the photoluminescence quantum yield by about two-fold and slightly changes the bandgap by similar to 0.1 eV. We demonstrate that these effects are governed by two factors: the Hammet constant of the substituents and their involvement in the pi-conjugation/hyperconjugation described by the effective conjugation length of the substituted oligomer. A detailed picture underlying the effect of the terminal substituents on the electronic, vibrational and optical properties of TPCOs is presented. Overall, the unraveled relationships between the structure and the properties of the substituted PTTPs should facilitate a rational design of pi-conjugated (co-)oligomers for efficient organic optoelectronic devices.

Sosorev A.Y. , Nuraliev M.K. , Feldman E.V. , Maslennikov D.R. , Borshchev O.V. , Skorotetcky M.S. , Surin N.M. , Kazantsev M.S. , Ponomarenko S.A. , Paraschuk D.Y.
Impact of terminal substituents on the electronic, vibrational and optical properties of thiophene-phenylene co-oligomers
Physical Chemistry Chemical Physics. 2019. V.21. N22. P.11578-11588. DOI: 10.1039/c9cp00910h WOS Scopus РИНЦ

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