Synthesis and photophysical properties of N-alkyl dithieno[3,2- b:2',3'- d]pyrrole based donor/acceptor-π-conjugated copolymers for solar-cell application

Cuc Kim Trinh; Gamal M Nassar; Nabiha I Abdo; Suhyun Jung; Wonbin Kim; Kwanghee Lee; Jae-Suk Lee

doi:10.1039/d2ra02608b

Synthesis and photophysical properties of N-alkyl dithieno[3,2- b:2',3'- d]pyrrole based donor/acceptor-π-conjugated copolymers for solar-cell application

RSC Adv. 2022 Jun 15;12(28):17682-17688. doi: 10.1039/d2ra02608b. eCollection 2022 Jun 14.

Authors

Cuc Kim Trinh¹, Gamal M Nassar^{2

3}, Nabiha I Abdo⁴, Suhyun Jung², Wonbin Kim², Kwanghee Lee², Jae-Suk Lee²

Affiliations

¹ Chemical Engineering in Advanced Materials and Renewable Energy Research Group, School of Engineering and Technology, Van Lang University Ho Chi Minh City Vietnam cuc.tk@vlu.edu.vn.
² School of Materials Science & Engineering, Gwangju Institute of Science and Technology (GIST) Gwangju 61005 Republic of Korea jslee@gist.ac.kr.
³ Department of Chemistry, Faculty of Science, Tanta University Tanta 31527 Egypt.
⁴ Higher Institute of Engineering and Technology New Borg Al Arab Alexandria Egypt.

Abstract

Two kinds of donor-acceptor π-conjugated copolymer based on poly{[N-hexyl-dithieno(3,2-b:2',3'-d)pyrrole-2,6-diyl]alt-[isoindigo]} (PDTP-IID) and poly{[N-hexyl-dithieno(3,2-b:2',3'-d)pyrrole-2,6-diyl]alt-[thiazol-2,5-diyl]} (PDTP-Thz) were investigated. These copolymers were synthesized via a Stille coupling reaction. The results showed the structure-property relationships of different donor-acceptor (D-A) combinations. The polymer structures and photophysical properties were characterized by ¹H NMR, TGA, DSC, UV-vis absorption spectroscopy, AFM, CV, and XRD measurement. Through UV-vis absorption and cyclic voltammetry (CV) measurements, it showed that the copolymers exhibit not only a low bandgap of 1.29 eV and 1.51 eV but also a deep highest occupied molecular orbital (HOMO) of -5.49 and -5.11 eV. Moreover, photovoltaic properties in combination with the fullerene derivatives were investigated. The device based on the copolymers with PC₇₁BM exhibited higher maximum power conversion efficiency and higher maximum short-circuit current density of 0.23% with 1.64 mA cm^-2 of PDTP-IID:PC₇₁BM and 0.13% with 1.11 mA cm^-2 of PDTP-Thz:PC₇₁BM than those of the copolymers with PC₆₁BM. Measurements performed for N-hexyl-dithieno(3,2-b:2',3'-d)pyrrole-based copolymers proved the potential of these polymers to be applied in optoelectronic applications.