Xiong Sixing, Hu Lin, Hu Lu, Sun Lulu, Qin Fei, Liu Xianjie, Fahlman Mats, Zhou Yinhua
Wuhan National Laboratory for Optoelectronics, and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China.
Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183, Linköping, Sweden.
Adv Mater. 2019 May;31(22):e1806616. doi: 10.1002/adma.201806616. Epub 2019 Jan 17.
Nonfullerene (NF) organic solar cells (OSCs) have been attracting significant attention in the past several years. It is still challenging to achieve high-performance flexible NF OSCs. NF acceptors are chemically reactive and tend to react with the low-temperature-processed low-work-function (low-WF) interfacial layers, such as polyethylenimine ethoxylated (PEIE), which leads to the "S" shape in the current-density characteristics of the cells. In this work, the chemical interaction between the NF active layer and the polymer interfacial layer of PEIE is deactivated by increasing its protonation. The PEIE processed from aqueous solution shows more protonated N than that processed from isopropyl alcohol solution, observed from X-ray photoelectron spectroscopy. NF solar cells (active layer: PCE-10:IEICO-4F) with the protonated PEIE interfacial layer show an efficiency of 13.2%, which is higher than the reference cells with a ZnO interlayer (12.6%). More importantly, the protonated PEIE interfacial layer processed from aqueous solution does not require a further thermal annealing treatment (only processing at room temperature). The room-temperature processing and effective WF reduction enable the demonstration of high-performance (12.5%) flexible NF OSCs.
在过去几年中，非富勒烯（NF）有机太阳能电池（OSCs）一直备受关注。实现高性能的柔性NF OSCs仍然具有挑战性。NF受体具有化学反应性，容易与低温处理的低功函数（low-WF）界面层发生反应，例如聚乙撑亚胺乙氧基化产物（PEIE），这导致电池电流密度特性呈“S”形。在这项工作中，通过增加PEIE的质子化来钝化NF活性层与聚合物界面层之间的化学相互作用。从X射线光电子能谱观察到，从水溶液中处理的PEIE比从异丙醇溶液中处理的PEIE显示出更多的质子化氮。具有质子化PEIE界面层的NF太阳能电池（活性层：PCE-10:IEICO-4F）的效率为13.2%，高于具有ZnO中间层的参考电池（12.6%）。更重要的是，从水溶液中处理的质子化PEIE界面层不需要进一步的热退火处理（仅在室温下处理）。室温处理和有效的功函数降低使得高性能（12.5%）的柔性NF OSCs得以展示。
