Effects of inserting keto-functionalized side-chains instead of imide-functionalized side-chain on the pyrrole backbone of 2,5-bis(2-thienyl)pyrrole-based polymers for organic solar cells

Autor: Myung Ho Hyun, Rajalingam Agneeswari, Insoo Shin, Yun Kyung Jung, Jung Hyun Jeong, Yanliang Liu, Vellaiappillai Tamilavan, Sung Heum Park, Youngeup Jin, Bo Ram Lee
Rok vydání: 2019
Předmět:
Zdroj: Journal of Photochemistry and Photobiology A: Chemistry. 371:387-394
ISSN: 1010-6030
DOI: 10.1016/j.jphotochem.2018.11.046
Popis: A 2,5-bis(2-thienyl)pyrrole (TPT)-based new monomer unit incorporating the electron-withdrawing 1-decanone (ketone) at the 3- and 4-positions of the pyrrole unit of TPT was prepared. The resulting keto-functionalized TPT unit (≈TPTK) was polymerized with distannyl derivatives of 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (BDTT), 4,7-bis(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT), and 3,6-bis(thiophen-2-yl)-2,5-dioctylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DKPP), to obtain three new polymers (P(BDTT-TPTK), P(DTBT-TPTK) and P(DKPP-TPTK)), respectively. The photophysical, electrochemical, and energy conversion efficiency of the TPTK-based polymers were thoroughly studied and compared with those of structurally similar polymers (P(BDTT-TPTI), P(DTBT-TPTI), and P(DKPP-TPTI)) incorporating an imide-functionalized TPT unit (≈ TPTI). Overall, the TPTK-based polymers showed a higher band-gap (Eg ≈ 2.42 eV, 1.92 eV, and 1.42 eV), deeper highest occupied molecular orbital (HOMO ≈ −5.58 eV, −5.48 eV, and −5.31 eV, respectively) energy levels and lower carrier mobilities than those of the corresponding TPTI-based polymers. These combined effects led to relatively poor solar to electrical energy conversion efficiency for TPTK-based polymers compared to those of TPTI-based polymers.
Databáze: OpenAIRE
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