Yikai Wang , Xiaolin Jiang , Haoming Song , Nan Wei , Yifan Wang , Xinjun Xu , Cuihong Li , Hao Lu , Yahui Liu , Zhishan Bo
{"title":"Thickness-insensitive, cyano-modified perylene diimide derivative as a cathode interlayer material for high-efficiency organic solar cells","authors":"Yikai Wang , Xiaolin Jiang , Haoming Song , Nan Wei , Yifan Wang , Xinjun Xu , Cuihong Li , Hao Lu , Yahui Liu , Zhishan Bo","doi":"10.3866/PKU.WHXB202406007","DOIUrl":null,"url":null,"abstract":"<div><div>Interlayer materials play a crucial role in achieving high efficiency in organic solar cells (OSCs). However, slight increases in film thickness often lead to significant charge accumulation and recombination, presenting a challenge for large-scale OSC device fabrication. Therefore, there is a pressing need for interlayer materials that are insensitive to variations in thickness. In this study, we synthesized a cost-effective cyano-modified perylene diimide (PDI) derivative, <strong>PDINBrCN</strong>, as an interlayer material. Compared to the analogous <strong>PDINBr</strong>, the introduction of cyano groups lowers the Lowest unoccupied molecular orbital (LUMO) energy level of the molecule, enhancing electron injection and charge transport efficiency. Additionally, <strong>PDINBrCN</strong> demonstrates excellent solubility in 2,2,2-trifluoroethanol (TFE) and effectively modifies the electrode work function, facilitating device fabrication through orthogonal solvent processing. When utilized as the cathode interlayer in D18:L8-BO devices, <strong>PDINBrCN</strong> achieved a high power conversion efficiency (PCE) of 18.83 % with a film thickness of 10 nm. Importantly, <strong>PDINBrCN</strong> maintained a PCE of 17.90 % even when the film thickness was increased to 50 nm. In contrast, the analogous PDI derivatives <strong>PDINBr</strong> and the star cathode interlayer material anthra [2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H, 9H)-tetrone (PDINN) achieved PCEs of 17.17 % and 17.06 %, respectively, at the same film thickness. Notably, <strong>PDINBrCN</strong> maintained a PCE of over 16 % even with an interlayer thickness of 80 nm, marking one of the best results for small molecule PDI derivatives as cathode interlayer materials at this thickness. Our findings demonstrate that <strong>PDINBrCN</strong> exhibits excellent processability, electrode work function adjustment capability, and crucially, thickness-insensitive properties. Therefore, <strong>PDINBrCN</strong> holds promise as an efficient and cost-effective cathode interlayer material, with potential for future commercial applications in OSCs.</div></div>","PeriodicalId":6964,"journal":{"name":"物理化学学报","volume":"41 3","pages":"Article 100027"},"PeriodicalIF":10.8000,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"物理化学学报","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1000681824000274","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Interlayer materials play a crucial role in achieving high efficiency in organic solar cells (OSCs). However, slight increases in film thickness often lead to significant charge accumulation and recombination, presenting a challenge for large-scale OSC device fabrication. Therefore, there is a pressing need for interlayer materials that are insensitive to variations in thickness. In this study, we synthesized a cost-effective cyano-modified perylene diimide (PDI) derivative, PDINBrCN, as an interlayer material. Compared to the analogous PDINBr, the introduction of cyano groups lowers the Lowest unoccupied molecular orbital (LUMO) energy level of the molecule, enhancing electron injection and charge transport efficiency. Additionally, PDINBrCN demonstrates excellent solubility in 2,2,2-trifluoroethanol (TFE) and effectively modifies the electrode work function, facilitating device fabrication through orthogonal solvent processing. When utilized as the cathode interlayer in D18:L8-BO devices, PDINBrCN achieved a high power conversion efficiency (PCE) of 18.83 % with a film thickness of 10 nm. Importantly, PDINBrCN maintained a PCE of 17.90 % even when the film thickness was increased to 50 nm. In contrast, the analogous PDI derivatives PDINBr and the star cathode interlayer material anthra [2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H, 9H)-tetrone (PDINN) achieved PCEs of 17.17 % and 17.06 %, respectively, at the same film thickness. Notably, PDINBrCN maintained a PCE of over 16 % even with an interlayer thickness of 80 nm, marking one of the best results for small molecule PDI derivatives as cathode interlayer materials at this thickness. Our findings demonstrate that PDINBrCN exhibits excellent processability, electrode work function adjustment capability, and crucially, thickness-insensitive properties. Therefore, PDINBrCN holds promise as an efficient and cost-effective cathode interlayer material, with potential for future commercial applications in OSCs.