Wang Jianqiu, Wang Yafei, Xian Kaihu, Qiao Jiawei, Chen Zhihao, Bi Pengqing, Zhang Tao, Zheng Zhong, Hao Xiaotao, Ye Long, Zhang Shaoqing, Hou Jianhui
State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Adv Mater. 2024 Jan;36(1):e2305424. doi: 10.1002/adma.202305424. Epub 2023 Nov 20.
All-polymer solar cells (all-PSCs) possess excellent operation stability and mechanical robustness than other types of organic solar cells, thereby attracting considerable attention for wearable flexible electron devices. However, the power conversion efficiencies (PCEs) of all-PSCs are still lagging behind those of small-molecule-acceptor-based systems owing to the limitation of photoactive materials and unsatisfactory blend morphology. In this work, a novel terpolymer, denoted as PBDB-TFCl (poly4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo[1,2-b:4,5-b″]dithiophene-1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c″]dithiophene-4,8-dione-4,8-bis(4-chloro-5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene), is used as an electron donor coupled with a ternary strategy to optimize the performance of all-PSCs. The addition of PBDB-TCl unit deepens the highest occupied molecular orbital energy level, reducing voltage losses. Moreover, the introduction of the guest donor (D18-Cl) effectively regulates the phase-transition kinetics of PBDB-TFCl:D18-Cl:PY-IT during the film formation, leading to ideal size of aggregations and enhanced crystallinity. PBDB-TFCl:D18-Cl:PY-IT devices exhibit a PCE of 18.6% (certified as 18.3%), judged as the highest value so far obtained with all-PSCs. Besides, based on the ternary active layer, the manufactured 36 cm flexible modules exhibit a PCE of 15.1%. Meanwhile, the ternary PSCs exhibit superior photostability and mechanical stability. In summary, the proposed strategy, based on molecular design and the ternary strategy, allows optimization of the all-polymer blend morphology and improvement of the photovoltaic performance for stable large-scale flexible PSCs.
全聚合物太阳能电池（all-PSC）比其他类型的有机太阳能电池具有出色的运行稳定性和机械强度，因此在可穿戴柔性电子设备方面备受关注。然而，由于光活性材料的限制和不理想的共混形态，all-PSC的功率转换效率（PCE）仍落后于基于小分子受体的系统。在这项工作中，一种新型三元聚合物，记为PBDB-TFCl（聚[4,8-双(5-(2-乙基己基)-4-氟噻吩-2-基)苯并[1,2-b:4,5-b″]二噻吩-1,3-双(2-乙基己基)-5,7-二(噻吩-2-基)-4H,8H-苯并[1,2-c:4,5-c″]二噻吩-4,8-二酮-4,8-双(4-氯-5-(2-乙基己基)噻吩-2-基)苯并[1,2-b:4,5-b']二噻吩），被用作电子供体，并结合三元策略来优化all-PSC的性能。PBDB-TCl单元的加入加深了最高占据分子轨道能级，降低了电压损失。此外，客体供体（D18-Cl）的引入有效地调节了PBDB-TFCl:D18-Cl:PY-IT在成膜过程中的相变动力学，导致形成理想尺寸的聚集体并提高了结晶度。PBDB-TFCl:D18-Cl:PY-IT器件的PCE为18.6%（认证值为18.3%），被认为是目前all-PSC所获得的最高值。此外，基于三元活性层制造的36厘米柔性模块的PCE为15.1%。同时，三元PSC表现出优异的光稳定性和机械稳定性。总之，基于分子设计和三元策略所提出的方法能够优化全聚合物共混形态，并改善用于稳定大规模柔性PSC的光伏性能。
