Synthesis, characterization and photovoltaic properties of low band gap donor-acceptor polymers containing benzodithiophene donor unit with fluorenylthiophene as 2D-conjugated side for organic solar cell application

• Published in: Molecular Crystals and Liquid Crystals Vol. 635; no. 1; pp. 45 - 56
• Main Authors: Kim, Taeik, Chakravarthi, Nallan, Kumarasamy, Gunasekar, Jin, Sung-Ho
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 12.08.2016; Taylor & Francis Ltd
• Subjects: Band gap; benzodithiophene; Bulk heterojunction solar cells; Chemical synthesis; Conversion; Displays; Energy conversion efficiency; Esters; low-band gap polymers; Photovoltaic cells; Polymers; Shoulders; Solar cells; Solar energy; Synthesis (chemistry); π-conjugated polymer
• ISSN: 1542-1406; 1563-5287; 1527-1943
• DOI: 10.1080/15421406.2016.1199999

Two donor−acceptor low band gap polymers P1 (octyl as solubilizing group) and P2 (ethylhexyl as solubilizing group) containing fluorenylthiophene-substituted benzoditihiophene as an electron-rich unit and 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione as an electron-deficient unit are designed and synthesized for polymer solar cells application. Compared with P2 based on ethyl hexyl group, P1 with octyl group displays well resolved vibronic shoulder peak in absorption spectra, stronger intermolecular interactions, and higher hole mobility. Polymer solar cells based on P1 and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM) exhibit a maximum power conversion efficiency of 1.78% under AM 1.5G illumination (100 mW/cm 2 ).