Yu Xueliang, Ding Pengfei, Yang Daobin, Yan Pengyu, Wang Hongqian, Yang Shuncheng, Wu Jie, Wang Zhongqiang, Sun He, Chen Zhenyu, Xie Lin, Ge Ziyi
Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
College of Electronic Information and Optical Engineering, Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan, 030024, China.
Angew Chem Int Ed Engl. 2024 Apr 24;63(18):e202401518. doi: 10.1002/anie.202401518. Epub 2024 Mar 27.
The hole-transporting material (HTM), poly (3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), is the most widely used material in the realization of high-efficiency organic solar cells (OSCs). However, the stability of PEDOT : PSS-based OSCs is quite poor, arising from its strong acidity and hygroscopicity. In addition, PEDOT : PSS has an absorption in the infrared region and high highest occupied molecular orbital (HOMO) energy level, thus limiting the enhancement of short-circuit current density (J) and open-circuit voltage (V), respectively. Herein, two asymmetric self-assembled molecules (SAMs), namely BrCz and BrBACz, were designed and synthesized as HTM in binary OSCs based on the well-known system of PM6 : Y6, PM6 : eC9, PM6 : L8-BO, and D18 : eC9. Compared with BrCz, BrBACz shows larger dipole moment, deeper work function and lower surface energy. Moreover, BrBACz not only enhances photon harvesting in the active layer, but also minimizes voltage losses as well as improves interface charge extraction/ transport. Consequently, the PM6 : eC9-based binary OSC using BrBACz as HTM exhibits a champion efficiency of 19.70 % with a remarkable J of 29.20 mA cm and a V of 0.856 V, which is a record efficiency for binary OSCs so far. In addition, the unencapsulated device maintains 95.0 % of its original efficiency after 1,000 hours of storage at air ambient, indicating excellent long-term stability.
空穴传输材料（HTM）聚（3,4 - 乙撑二氧噻吩）聚（苯乙烯磺酸盐）（PEDOT : PSS）是实现高效有机太阳能电池（OSC）中使用最广泛的材料。然而，基于PEDOT : PSS的OSC稳定性相当差，这源于其强酸性和吸湿性。此外，PEDOT : PSS在红外区域有吸收且最高占据分子轨道（HOMO）能级较高，从而分别限制了短路电流密度（J）和开路电压（V）的提高。在此，基于著名的PM6 : Y6、PM6 : eC9、PM6 : L8 - BO和D18 : eC9体系，设计并合成了两种不对称自组装分子（SAMs），即BrCz和BrBACz，作为二元OSC中的HTM。与BrCz相比，BrBACz表现出更大的偶极矩、更深的功函数和更低的表面能。此外，BrBACz不仅增强了活性层中的光子捕获，还最小化了电压损失并改善了界面电荷提取/传输。因此，以BrBACz作为HTM的基于PM6 : eC9的二元OSC展现出19.70 %的最优效率，显著的J为29.20 mA cm，V为0.856 V，这是迄今为止二元OSC的最高效率记录。此外，未封装的器件在空气环境中储存1000小时后仍保持其原始效率的95.0 %，表明具有出色的长期稳定性。
