Xing Zhou, Li Shu-Hui, Xie Fang-Fang, Xu Piao-Yang, Deng Lin-Long, Zhong Xinxian, Xie Su-Yuan
State Key Lab for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China.
ACS Appl Mater Interfaces. 2020 Aug 5;12(31):35081-35087. doi: 10.1021/acsami.0c10074. Epub 2020 Jul 27.
In structure perovskite solar cells (PSCs), the most prevalent electron transport layer (ETL), [6, 6]-phenyl-C-butyric acid methyl ester (PCBM), acts as both electron extractor and protective coverage to the underlayer perovskite. Notably, multifunctional mixed fullerene ETLs show great potential in further improving both the power conversion efficiency (PCE) and stability of PSCs compared to the single PCBM ETL. In this work, we reported the mixed fullerene ETLs comprising of PCBM and its two analogs with different length of fluorocarbon chains, [6, 6]-phenyl-C-buryric acid 1H,1H-trifluoro-1-ethyl ester (abbreviated, CF-PCBM) and [6, 6]-phenyl-C-buryric acid 1H, 1H-tridecafluoro-1-heptyl ester (abbreviated, CF-PCBM). We obtained excellent PCEs of 18.37% and 17.71% for 1 wt % CF-PCBM- and CF-PCBM-based PSCs (1 wt % addition of PCBM) with CHNHPbI (MAPbI) perovskites, respectively. Moreover, champion PCEs of ∼19% were obtained based on the CsFAMAPbIBr perovskites. Subsequent experiments demonstrated that the fluorocarbon chains of CF-PCBM and CF-PCBM assembled at the surfaces of ETLs with the formation of thin-layer moisture-resistant protective coverage above perovskite. Results show that it significantly retarded water penetrating down to perovskite layers and led to optimal humidity stability under ambient atmosphere.
在结构钙钛矿太阳能电池（PSC）中，最常见的电子传输层（ETL），[6,6]-苯基-C-丁酸甲酯（PCBM），既作为电子提取器，又对下层钙钛矿起到保护覆盖作用。值得注意的是，与单一的PCBM ETL相比，多功能混合富勒烯ETL在进一步提高PSC的功率转换效率（PCE）和稳定性方面显示出巨大潜力。在这项工作中，我们报道了由PCBM及其两种具有不同长度碳氟链的类似物组成的混合富勒烯ETL，[6,6]-苯基-C-丁酸1H,1H-三氟-1-乙酯（简称CF-PCBM）和[6,6]-苯基-C-丁酸1H,1H-十三氟-1-庚酯（简称CF-PCBM）。对于基于1 wt% CF-PCBM和CF-PCBM的PSC（添加1 wt%的PCBM）与CHNHPbI（MAPbI）钙钛矿，我们分别获得了18.37%和17.71%的优异PCE。此外，基于CsFAMAPbIBr钙钛矿获得了约19%的最佳PCE。随后的实验表明，CF-PCBM和CF-PCBM的碳氟链在ETL表面组装，在钙钛矿上方形成了防潮薄层保护覆盖层。结果表明，它显著阻碍了水渗透到钙钛矿层，并在环境大气下导致了最佳的湿度稳定性。
