Wang Chang, Dou Yichen, Wang Yi, Huang Fuzhi, Ku Zhiliang, Lu Jianfeng, Cheng Yi-Bing
State Key Laboratory of Advanced Technologies for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, Hubei Province, China.
Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory, Foshan 528216, Guangdong Province, China.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22601-22606. doi: 10.1021/acsami.2c01732. Epub 2022 May 9.
Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted great research attention due to their outstanding optoelectronic properties. The low-temperature synthesizing process of organic-inorganic hybrid perovskites can provide a significant advantage of reducing the manufacturing cost of solar cells. However, at the same time, this also brings challenges to PSCs in the form of long-term stability. Because of the low vacancy formation energy, organic-inorganic hybrid perovskites suffer from serious ion migration issue. Also, this ion migration will lead to a series of stability problems, which can hardly be addressed by encapsulation. Currently, modifying the surface of perovskite by an ion-blocking layer is a common strategy for achieving highly stable PSCs. These strategies could effectively address the stability issues caused by the interfacial ion diffusion between perovskite and the charge transport layer. However, the ion migration inside the perovskite layer could be still a knotty problem, which is difficult to be solved through surface modification. Herein, we propose a novel strategy to mitigate the internal ion migration by inserting two-dimensional graphene oxide (GO) into a perovskite layer. Close-space sublimation and ultrasonic spray coating were employed to prepare perovskite and GO layers, respectively. We found that the ion migration in the as-prepared perovskite/GO/perovskite can be successfully mitigated by the GO interlayer. As a result, the champion PSC with a GO interlayer maintained 85% of its initial power conversion efficiency (PCE) after 96 h of continuous illumination. By contrast, the efficiency of the PSC without a GO interlayer declined rapidly and maintained only 50% of the initial value. We believe that this novel interlayer strategy could provide a new idea and approach to preparing highly stable PSCs.
有机-无机杂化钙钛矿太阳能电池（PSCs）因其优异的光电性能而备受研究关注。有机-无机杂化钙钛矿的低温合成工艺能够显著降低太阳能电池的制造成本。然而，与此同时，这也给PSCs带来了长期稳定性方面的挑战。由于空位形成能较低，有机-无机杂化钙钛矿存在严重的离子迁移问题。而且，这种离子迁移会导致一系列稳定性问题，通过封装很难解决。目前，通过离子阻挡层修饰钙钛矿表面是实现高稳定性PSCs的常用策略。这些策略能够有效解决钙钛矿与电荷传输层之间界面离子扩散引起的稳定性问题。然而，钙钛矿层内部的离子迁移仍然是一个棘手的问题，难以通过表面修饰来解决。在此，我们提出一种新颖的策略，通过在钙钛矿层中插入二维氧化石墨烯（GO）来减轻内部离子迁移。分别采用近距离升华和超声喷雾涂层法制备钙钛矿层和GO层。我们发现，制备的钙钛矿/GO/钙钛矿中的离子迁移能够通过GO中间层成功减轻。结果，具有GO中间层的最佳PSCs在连续光照96小时后仍保持其初始功率转换效率（PCE）的85%。相比之下，没有GO中间层的PSCs效率迅速下降，仅保持初始值的50%。我们相信，这种新颖的中间层策略能够为制备高稳定性PSCs提供新的思路和方法。
