N-Type Small Molecule Electron Transport Layers with Excellent Surface Energy and Moisture Resistance Siloxane for Non-Fullerene Organic Solar Cells.
N-Type Small Molecule Electron Transport Layers with Excellent Surface Energy and Moisture Resistance Siloxane for Non-Fullerene Organic Solar Cells.
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DOI：
10.1002/smll.202308961
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发表时间：
2023-12
期刊：
影响因子：
13.3
通讯作者：
Yubing Li;Dan Zhou;Liangjing Han;Jianwei Quan;Fang Wang;Xufang Yang;Lin Hu;Jianru Wang;Haitao Xu;Lie Chen
中科院分区：
文献类型：
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作者：
Yubing Li;Dan Zhou;Liangjing Han;Jianwei Quan;Fang Wang;Xufang Yang;Lin Hu;Jianru Wang;Haitao Xu;Lie Chen
电子传输层（ETL）通常含有用于增强性能和降低功函数的极性基团。然而，具有高表面能的极性基团可能导致较差的界面相容性，这对ETL平衡稳定性和性能提出了挑战。在此，合成了两种具有低表面能硅氧烷的共轭小分子ETL，即PDI-Si和PDIN-Si。具有低表面能的硅氧烷不仅增强了ETL与有源层之间的界面相容性，而且提高了器件的防潮稳定性。令人印象深刻的是，胺官能化的PDIN-Si可以同时表现出显著的n型自掺杂特性和出色的防潮稳定性。界面接触和形貌的优化使得具有PDIN-Si的PM 6：Y 6基OSC能够实现15.87%的功率转换效率（PCE），这略上级经典ETL PDINO器件的功率转换效率（15.27%），并且当PDIN-Si膜厚度达到28 nm时，PCE保持在13.19%（约83%），这表明PDIN-Si具有令人满意的厚度不敏感性以促进卷对卷加工。令人兴奋的是，在湿度高于45%的环境中储存120小时后，具有PDIN-Si作为ETL的未封装器件保持在初始PCE值的75%，而具有PDINO作为ETL的器件仅为50%。
Electron transport layers (ETLs) generally contain polar groups for enhancing performance and reducing the work function. Nevertheless, the polar group with high surface energy may cause inferior interfacial compatibility, which challenges the ETLs to balance stability and performance. Here, two conjugated small molecules of ETLs with low surface energy siloxane, namely PDI-Si and PDIN-Si, are synthesized. The siloxane with low surface energy not only enhances the interfacial compatibility between ETLs and active layers but also improves the moisture-proof stability of the device. Impressively, the amine-functionalized PDIN-Si can simultaneously exhibit conspicuous n-type self-doping properties and outstanding moisture-proof stability. The optimization of interfacial contact and morphology enables the PM6:Y6-based OSC with PDIN-Si to achieve a power conversion efficiency (PCE) of 15.87%, which is slightly superior to that of classical ETL PDINO devices (15.27%), and when the PDIN-Si film thickness reaches 28 nm, the PCE remains at 13.19% (≈83%), which indicates that PDIN-Si has satisfactory thickness insensitivity to facilitate roll-to-roll processing. Excitingly, after 120 h of storage in an environment with humidity above 45%, the unencapsulated device with PDIN-Si as ETL remains at 75% of the initial PCE value, while the device with PDINO as ETL is only 50%.