Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics , The University of Queensland , Brisbane 4072 , Australia.
Institute of Physics and Astronomy , University of Potsdam , Karl-Liebknecht-Str. 24-25 , D-14476 Potsdam-Golm , Germany.
ACS Appl Mater Interfaces. 2018 Jun 27;10(25):21681-21687. doi: 10.1021/acsami.8b02503. Epub 2018 Jun 18.
Engineering the interface between the perovskite absorber and the charge-transporting layers has become an important method for improving the charge extraction and open-circuit voltage ( V) of hybrid perovskite solar cells. Conjugated polymers are particularly suited to form the hole-transporting layer, but their hydrophobicity renders it difficult to solution-process the perovskite absorber on top. Herein, oxygen plasma treatment is introduced as a simple means to change the surface energy and work function of hydrophobic polymer interlayers for use as p-contacts in perovskite solar cells. We find that upon oxygen plasma treatment, the hydrophobic surfaces of different prototypical p-type polymers became sufficiently hydrophilic to enable subsequent perovskite junction processing. In addition, the oxygen plasma treatment also increased the ionization potential of the polymer such that it became closer to the valance band energy of the perovskite. It was also found that the oxygen plasma treatment could increase the electrical conductivity of the p-type polymers, facilitating more efficient charge extraction. On the basis of this concept, inverted MAPbI perovskite devices with different oxygen plasma-treated polymers such as P3HT, P3OT, polyTPD, or PTAA were fabricated with power conversion efficiencies of up to 19%.
在钙钛矿吸收层和电荷传输层之间进行工程设计，已成为提高杂化钙钛矿太阳能电池的电荷提取和开路电压（V）的重要方法。共轭聚合物特别适合形成空穴传输层，但它们的疏水性使得难以在钙钛矿吸收层的顶部进行溶液处理。在此，我们引入氧等离子体处理作为一种简单的方法，以改变疏水性聚合物层的表面能和功函数，用作钙钛矿太阳能电池的 p 型接触。我们发现，经过氧等离子体处理后，不同原型 p 型聚合物的疏水性表面变得足够亲水，从而能够进行后续的钙钛矿结处理。此外，氧等离子体处理还增加了聚合物的电离势，使其更接近钙钛矿的价带能量。还发现，氧等离子体处理可以提高 p 型聚合物的电导率，从而更有效地提取电荷。基于这一概念，我们制备了具有不同氧等离子体处理聚合物（如 P3HT、P3OT、polyTPD 或 PTAA）的倒置 MAPbI 钙钛矿器件，其功率转换效率高达 19%。
