Li Chi, Ganesan Paramaguru, Li Yuheng, Tang Shicheng, Wang Yao, Liu Chunming, Liang Lusheng, Yu Yaming, Yusoff Abd Rashid Bin Mohd, Grätzel Michael, Gao Peng
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
Laboratory for Advanced Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institute, Chinese Academy of Sciences, Xiamen 361021, China.
J Am Chem Soc. 2025 Jul 23;147(29):25738-25749. doi: 10.1021/jacs.5c07357. Epub 2025 Jul 8.
Work function modulation of transparent conductive oxides via self-assembled monolayers (SAMs) facilitates efficient hole or electron extraction in optoelectronic devices. However, recent SAMs for perovskite solar cells (PSCs) diverge from traditional interfacial dipole orientation design principles, instead leveraging electron-rich and electron-deficient surface modifications. In light of these discrepancies, this study systematically analyses electron-deficient materials of varying strength, revealing the dominance of surface modifications over interfacial dipole orientation. Specifically, modulating the electron-withdrawing strength by replacing the carboxylic acid group (Bpy-COOH) with a cyanoacrylic acid moiety (Bpy-CAA) in dual-functional bipyridine-based electron-selective molecular layers (ESMLs) enhances adsorption, electron extraction, and passivation in n-i-p PSCs. Consequently, Bpy-CAA devices achieve 23.98% efficiency, surpassing Bpy-COOH-based devices (23.20%), and maintain an impressive 21.63% efficiency in 1 cm cells, the highest reported for 1 cm n-i-p PSCs utilizing organic ESMLs. A remarkable efficiency of 26.00% is achieved by integrating Bpy-CAA as an interfacial layer into SnO/ESML/perovskite contacts while adapting this architecture into four-terminal perovskite/silicon tandem solar cells (4T-P/STSCs) yields an impressive efficiency of 30.83%, ranking among the highest reported efficiencies for 4T-P/STSCs. Overall, this work demonstrates that the electronic nature of the molecule is more decisive than dipole orientation for efficient electron extraction, and tailoring the dual-functional ESMLs effectively facilitated the development of efficient single-junction PSCs and 4T-P/STSCs.
通过自组装单分子层（SAMs）对透明导电氧化物的功函数进行调制，有助于在光电器件中实现高效的空穴或电子提取。然而，最近用于钙钛矿太阳能电池（PSC）的SAMs背离了传统的界面偶极取向设计原则，转而利用富电子和缺电子的表面修饰。鉴于这些差异，本研究系统地分析了不同强度的缺电子材料，揭示了表面修饰相对于界面偶极取向的主导作用。具体而言，在基于双功能联吡啶的电子选择性分子层（ESMLs）中，通过用氰基丙烯酸部分（Bpy-CAA）取代羧酸基团（Bpy-COOH）来调节吸电子强度，可增强n-i-p型PSC中的吸附、电子提取和钝化作用。因此，Bpy-CAA器件实现了23.98%的效率，超过了基于Bpy-COOH的器件（23.20%），并且在1平方厘米的电池中保持了令人印象深刻的21.63%的效率，这是利用有机ESMLs的1平方厘米n-i-p型PSC所报道的最高效率。通过将Bpy-CAA作为界面层集成到SnO/ESML/钙钛矿接触中，实现了26.00%的显著效率，同时将这种结构应用于四端钙钛矿/硅串联太阳能电池（4T-P/STSCs），获得了令人印象深刻的30.83%的效率，跻身于4T-P/STSCs所报道的最高效率之列。总体而言，这项工作表明，对于高效的电子提取，分子的电子性质比偶极取向更具决定性，并且定制双功能ESMLs有效地促进了高效单结PSC和4T-P/STSCs的发展。
