Enhancing efficiency with fluorinated interlayers in small molecule organic solar cells

Hsieh Cheng Han, Chi Ang Tseng, Chan Yi Du, Abhijit Ganguly, Cheong Wei Chong, Sheng Bo Wang, Chi Feng Lin, Sheng Hsiung Chang, Chao Chin Su, Jiun Haw Lee, Kuei Hsien Chen, Li Chyong Chen

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

This study presents a simple approach to improve the performance of small molecule based organic solar cells (OSCs) by inserting a fluorinated buffer layer (e.g., PFAS) at the hetero-interface of bilayer devices. As demonstrated in this work, the PFAS modification reduces the surface energy of the conventional PEDOT:PSS photoanode and results in a significant improvement in the pentacene based OSC. The passivated PEDOT:PSS surface after PFAS modification has a lower interface energy with pentacene and facilitates 3D single crystalline (dendritic-like) phase pentacene growth. Concurrently, the accumulated negative charges of the fluorinated PFAS layer result in the development of interfacial dipole moments that in turn lead to an enhanced built-in potential across the devices, and consequently enhanced hole transport efficiency. Improved performance of the modified OSCs is evident from the ∼97% enhancement in efficiency from 0.88% to 1.73%, along with the open-circuit voltage improvement from 0.29 to 0.42 V. As well as improving the photovoltaic performance, the PFAS treatment also enhances the stability of the device under high temperature annealing, which is essential in the fabrication process.

Original languageEnglish
Pages (from-to)22899-22905
Number of pages7
JournalJournal of Materials Chemistry
Volume22
Issue number43
DOIs
Publication statusPublished - 2012 Nov 21

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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