Alkyl-thiophene-alkyl linkers to construct double-cable conjugated polymers for single-component organic solar cells

In this work, semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct doublecable polymers. Three alkyl units, propyl (C 3 H 6 ), hexyl (C 6 H 12 ), and dodecyl (C 12 H 24 ), are applied as semirigid linkers, yielding three double-cable polymers: PBC6-T, PBC12-T, and PBC24-T, respectively. PBC12-T which uses C 6 H 12 -thiophene-C 6 H 12 linkers is found to exhibit the best device efficiency of 5.56%, while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65% and 1.09% in single-component organic solar cells (SCOSCs). Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport, resulting in better efficiencies. Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers, and it shows the importance of the linker length for the photovoltaic performance of SCOSCs. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.