Synthesis of a thiophene derivative and its effects as an additive on the performance of solar cells

Abstract

Effects of a newly synthesized additive, 2,2’5,5’-tetrathiophene-3,3’-hexyldithiophene (TTH), on the performance of polymer solar cells (PSCs) based on poly(3-hexylthiophene):[6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PCBM) bulk-heterojuction were investigated. The PSC with a non-annealed P3HT:PCBM:TTH blend film showd an increase in the short-circuit current and the fill factor, resulting in a significant enhancement in the power conversion efficiency, compared to that of a reference cell without the TTH additive. It was revealed that the addition of 5wt% TTH to the P3HT:PCBM blend film facilitated the crystallization (ordering) of P3HT chains without even post-thermal annealing, leading to a higher absorbance and a larger crystal size of P3HT, and thereby increasing the short-circuit current and the fill factor.

Keywords:

• thiophene derivative
• polymer solar cell
• P3HT
• PCBM
• post-thermal annealing

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT) (No. NRF-2016R1A2B1015037). This work was also supported by the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20194010201760).