Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), School of Flexible Electronics (Future Technologies), Nanjing Tech University, Nanjing 211816, Jiangsu, China.
School of Chemical Engineering, Center for Antibonding Regulated Crystals, Sungkyunkwan University, Suwon 16419, Republic of Korea.
ACS Appl Mater Interfaces. 2023 May 3;15(17):21152-21161. doi: 10.1021/acsami.3c02233. Epub 2023 Apr 19.
Electron transport layers (ETLs) are imperative in n-i-p structured perovskite solar cells (PSCs) because of their capability to affect light propagation, electron extraction, and perovskite crystallization, and any mismatch of optical constants, band position, and surface potential between the ETLs and the perovskites can cause unintentional optical and electrical losses. Herein, an antireflective and energetic cascade bilayer ETL with ubiquitously used SnO and TiO was constructed at 150 °C for PSCs, and the in-depth mechanism for performance improvement was systematically unraveled. It was revealed that the construction of an ETL with gradually increasing refractive indices can circumvent light reflection loss, resulting in enhanced photocurrent. The combined ETL forms an energetic cascade to promote electronic conductivity and facilitate electron extraction with reduced energy loss. Moreover, topologic perovskite growth with improved crystallinity and vertical orientation was preferred owing to the relative dewetting behavior, leading to reduced defect states and enhanced carrier mobility in the perovskite layer.
电子传输层（ETL）在 n-i-p 结构钙钛矿太阳能电池（PSC）中是必不可少的，因为它们能够影响光传播、电子提取和钙钛矿结晶，而 ETL 和钙钛矿之间的光学常数、能带位置和表面电势的任何不匹配都可能导致不必要的光和电损耗。在此，在 150°C 下为 PSCs 构建了具有普遍使用的 SnO 和 TiO 的具有反反射和能量级联双层 ETL，并且系统地揭示了性能提高的深入机制。结果表明，构建具有逐渐增加的折射率的 ETL 可以避免光反射损失，从而提高光电流。组合的 ETL 形成了一个能量级联，以促进电子导电性并促进电子提取，同时减少能量损失。此外，由于相对的去湿行为，优先选择具有改善结晶度和垂直取向的拓扑钙钛矿生长，从而减少钙钛矿层中的缺陷态并提高载流子迁移率。
