Polythiophenes with alkylthiophene side chains for efficient polymer solar cells

• Published in: Polymer (Guilford) Vol. 274; p. 125890
• Main Authors: He, Jiangting, Liang, Ziqi, Lin, Linlin, Liang, Shifeng, Xu, Jie, Ni, Wang, Li, Miaomiao, Geng, Yanhou
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 02.05.2023
• Subjects: alkylthiophene side chains; intermolecular interaction; Polythiophene derivatives; alkylthiophene side chains; Polythiophene derivatives; intermolecular interaction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2023.125890

We synthesized two polythiophene derivatives with alkylthiophene side chains, named PT4T-0F and PT4T-2F. The introduction of alkylthiophene side chains endowed PT4T-0F with more ordered edge-on stacking in film, resulting in higher hole mobility of 0.45 cm2V−1s−1 in organic field-effect transistors in comparison to P3HT. Further introducing fluorine atoms, a mainly face-on orientation was achieved for PT4T-2F neat film, which was facilitated to charge transport and collection in polymer solar cells (PSCs). Using F8IC as acceptor, the PSC devices based on PT4T-2F achieved the champion efficiency of 10.48%, owing to the appropriate film morphology with moderate phase separation and favorable face-on molecular orientation. Such efficiency greatly outperformed those of PT4T-0F (2.85%) and P3HT (0.35%) based devices. [Display omitted] •Two polythiophene derivatives with alkylthiophene side chains, i.e., PT4T-0F and PT4T-2F were designed and synthesized.•Compared with P3HT, PT4T-0F and PT4T-2F displayed more ordered molecular packing and decreased energy levels.•A PCE of 10.48% was achieved by PT4T-2F based polymer solar cells.•Both moderate crystallinity and good miscibility of the blend were critical for obtaining proper film morphology.