Comparative study of aliphatic vs. aromatic substituted perylenediimide as electron transport layer material. (15th May 2021)

• Record Type: Journal Article
• Authors: Bhardwaj, Komal; Naqvi, Samya; Kumar, Rachana
• Is Part Of: Solar energy. Volume 220(2021)
• Page Start: 608
• Page End: 616
• Publication Date: 2021-05-15
• Subjects: Perylene diimide -- Organic solar cells -- Excitonic solar cells -- Solution processable -- Transport layer; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2021.04.010
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A comparative study has been performed for the device properties of two quaternary salts of PDI derivatives (PDI-Q) having aliphatic / aromatic substituents at imide position. PDI-Q derivatives show suitable properties to be used as ETL like high transmittance in visible region, suitable HOMO-LUMO energy levels and good electron mobility. Device with PDI-EDAQ with aliphatic substitution shows better device performance compared to PDI-PyQ with aromatic substituent due to better electron transport in the former improving the fill factor. Theoretical simulation has also been performed to understand the difference in device properties of the two materials. Abstract: This work describes the study of solution processable perylene diimide (PDI) derivatives bearing aliphatic (PDI-EDAQ) and aromatic (PDI-PyQ) substituents at imide position as electron transport layer (ETL) material for organic solar cells. The PDI derivatives are easy to synthesize and most importantly soluble in methanol for processing feasibility. The materials have been characterized for their opto-electronic and electrochemical properties. The electron mobility was calculated by fabricating electron only devices and finally were tested PDI derivatives in inverted organic solar cell devices as ETL material using PTB7:PC71 BM as active layer. Average power conversion efficiency was found to be 4.2% and 2.2% for PDI-EDAQ and PDI-PyQ based devices respectively. The champion device for PDI-EDA showed efficiency ~4.5%. The device properties have been compared with standard ZnO ETL devices and by theoretical simulation an explanation has been provided for observed behaviour.