The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have reached 18% recently, which have already met the demand of practical application. However, these outstanding results were generally achieved with donor-acceptor (D-A) type copolymer donors, which can hardly fulfill the low-cost large-scale production due to their complicated synthesis processes. Therefore, developing polymer donors with simple chemical structures is urgent for realizing low-cost OSCs. Polythiophene (PT) derivatives are currently regarded as promising candidates for such kind of donor materials, which has been illustrated in many works. In this work, two new alkylthio substituted PT derivatives, P301 and P302, were synthesized and tested as donors in the OSCs using Y5 as the acceptor. In comparison, the introduction of fluorine atoms on the backbone of P302 can not only downshift the energy levels, but also greatly improve the phase separation morphologies of the active layers, which is ascribed to the enhanced aggregation effect and the reduced miscibility with the non-fullerene acceptor. As a result, the P302:Y5-based OSC exhibits a significantly improved PCE of 9.65% than that of P301:Y5-based one, indicating the important role of fluorination in the construction of efficient PT derivative donors.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |