Graduate School of Convergence Science and Technology, and Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Republic of Korea.
Nanoscale. 2018 Jul 9;10(26):12588-12594. doi: 10.1039/c8nr00292d.
Interconnection layers (ICLs) for polymer tandem solar cells reported so far are limited in materials' choice and layer structure, because of a requirement that the ICLs must prevent the penetration of solvents used for the top cells. In this research, it is demonstrated that depositing the active layer of the top subcell using a dry thin-film transfer technique allows for incorporation of an ICL composed of vacuum deposited materials in a polymer tandem cell, providing a large degree of freedom in ICL design. Specifically, a polymer tandem solar cell was fabricated using an ICL composed of bathocuproine:silver/silver islands/1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (BCP:Ag/Ag islands/HAT-CN), where the thicknesses of the BCP:Ag and Ag island layers are precisely controlled at the nanoscale to facilitate the transport of electrons generated in the bottom subcell and to ensure their efficient recombination with holes generated in the top subcell. Consequently, the tandem device featuring the optimized ICL, whose active layers are composed of poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) and poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)]:[6,6]-phenyl-C71-butyric acid methyl ester (PCPDTBT:PC71BM), exhibits an open-circuit voltage of 1.20 V, which is equal to the sum of the open-circuit voltages of the two subcells, with a fill factor (FF) of 0.60 almost identical to the FFs of the subcells.
迄今为止，报道的聚合物串联太阳能电池的互连层（ICLs）在材料选择和层结构方面受到限制，因为需要 ICL 阻止用于顶部电池的溶剂渗透。在这项研究中，证明使用干法薄膜转移技术沉积顶部子电池的活性层允许将由真空沉积材料组成的 ICL 结合到聚合物串联电池中，从而在 ICL 设计方面提供了很大的自由度。具体来说，使用由铜酞菁：银/银岛/1,4,5,8,9,11-六氮杂三苯六碳腈（BCP:Ag/Ag 岛/HAT-CN）组成的 ICL 制造了聚合物串联太阳能电池，其中 BCP:Ag 和 Ag 岛层的厚度精确地控制在纳米尺度，以促进底部子电池中产生的电子的传输，并确保它们与顶部子电池中产生的空穴有效复合。因此，具有优化 ICL 的串联器件，其活性层由聚（3-己基噻吩）：[6,6]-苯基-C61-丁酸甲酯（P3HT：PC61BM）和聚[2,6-（4,4-双（2-乙基己基）-4H-环戊并[2,1-b;3,4-b']二噻吩）-交替-4,7-（2,1,3-苯并噻二唑）]：[6,6]-苯基-C71-丁酸甲酯（PCPDTBT：PC71BM）组成，表现出 1.20 V 的开路电压，这等于两个子电池的开路电压之和，填充因子（FF）为 0.60，几乎与子电池的 FF 相同。
