Seo Jooyeok, Nam Sungho, Kim Hwajeong, Bradley Donal D C, Kim Youngkyoo
Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
Nanoscale Horiz. 2019 Mar 1;4(2):464-471. doi: 10.1039/c8nh00319j. Epub 2018 Dec 13.
Organic solar cells based on solution processes have strong advantages over conventional silicon solar cells due to the possible low-cost manufacturing of flexible large-area solar modules at low temperatures. However, the benefit of the low temperature process is diminished by a thermal annealing step at high temperatures (≥200 °C), which cannot be practically applied for typical plastic film substrates with a glass transition temperature lower than 200 °C, for inorganic charge-collecting buffer layers such as zinc oxide (ZnO) in high efficiency inverted-type organic solar cells. Here we demonstrate that novel hybrid electron-collecting buffer layers with a particular nano-crater morphology, which are prepared by a low-temperature (150 °C) thermal annealing process of ZnO precursor films containing poly(2-ethyl-2-oxazoline) (PEOz), can deliver a high efficiency (12.35%) similar to the pristine ZnO layers prepared by the conventional high-temperature process (200 °C) for inverted-type polymer:nonfullerene solar cells. The nano-crater morphology was found to greatly enhance the stability of solar cells due to improved adhesion between the active layers and ZnO:PEOz hybrid buffer layers.
基于溶液法制备的有机太阳能电池相较于传统硅太阳能电池具有显著优势，因为其有可能在低温下以低成本制造柔性大面积太阳能组件。然而，高温（≥200°C）热退火步骤会削弱低温工艺的优势，对于高效倒置型有机太阳能电池中诸如氧化锌（ZnO）之类的无机电荷收集缓冲层而言，这一高温热退火步骤实际上无法应用于玻璃化转变温度低于200°C的典型塑料薄膜基板。在此，我们证明了一种具有特定纳米坑形态的新型混合电子收集缓冲层，该缓冲层通过对含有聚（2-乙基-2-恶唑啉）（PEOz）的ZnO前驱体薄膜进行低温（150°C）热退火工艺制备而成，对于倒置型聚合物：非富勒烯太阳能电池，其可实现与通过传统高温工艺（200°C）制备的原始ZnO层相似的高效率（12.35%）。由于活性层与ZnO:PEOz混合缓冲层之间的附着力得到改善，发现纳米坑形态极大地提高了太阳能电池的稳定性。
