A new low-bandgap polymer acceptor based on benzotriazole for efficient all-polymer solar cells

• Published in: Journal of Central South University Vol. 28; no. 7; pp. 1919 - 1931
• Main Authors: Li, Zhe, Chen, Hong-gang, Yuan, Jun, Zou, Jie, Li, Jing, Guan, Hui-lan, Zou, Ying-ping
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.07.2021; Springer Nature B.V
• Subjects: Benzotriazole; Circuits; Energy conversion efficiency; Energy gap; Engineering; Metallic Materials; Morphology; Open circuit voltage; Photovoltaic cells; Polymers; Short circuit currents; Solar cells; Thermal stability; 窄带隙; low-bandgap; 全聚合物太阳电池; 能量转换效率; power conversion efficiency; 聚合物受体; all-polymer solar cells; polymer acceptor; benzotriazole; 苯并三氮唑
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-021-4741-7

The rational design of polymer acceptors with strong and broad absorption is critical to improve photovoltaic performance. In this work, a new polymer acceptor PY9-T based on heptacyclic benzotriazole (Y9-C16) as a building block and thiophene unit as the linking unit was synthesized, which exhibited a low bandgap (1.37 eV) and a high extinction coefficient of the neat film (1.44×10 5 cm −1 ). When PY9-T was blended with the wide bandgap polymer donor PBDB-T, the all-polymer solar cells (APSCs) showed a high power conversion efficiency (PCE) of 10.45% with both high open circuit voltage of 0.881 V and short-circuit current density of 19.82 mA/cm 2 . In addition, APSCs based on PY9-T show good thermal stability, as evidenced by slight changes morphologies when annealed at 100 °C. These results suggest that Y9-C16 provides a new building block to develop efficient and stable polymer acceptors.