Zone-refinement effect in small molecule-polymer blend semiconductors for organic thin-film transistors

Yeon Sook Chung, Nayool Shin, Jihoon Kang, Youngeun Jo, Vivek M. Prabhu, Sushil K. Satija, R. Joseph Kline, Dean M. DeLongchamp, Michael F. Toney, Marsha A. Loth, Balaji Purushothaman, John E. Anthony, Do Y. Yoon

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


The blend films of small-molecule semiconductors with insulating polymers exhibit not only excellent solution processability but also superior performance characteristics in organic thin-film transistors (OTFTs) over those of neat small-molecule semiconductors. To understand the underlying mechanism, we studied triethylsilylethynyl anthradithiophene (TESADT) with small amounts of impurity formed by weak UV exposure. OTFTs with neat impure TESADT had drastically reduced field-effect mobility (<10-5 cm2/(V s)), and a disappearance of the high-temperature crystal phase was observed for neat impure TESADT. However, the mobility of the blend films of the UV-exposed TESADT with poly(R-methylstyrene) (PαMS) is recovered to that of a fresh TESADT-PαMS blend (0.040 cm2/(V s)), and the phase transition characteristics partly return to those of fresh TESADT films. These resultsarecorroboratedbyOTFTresultson"aged"TIPS-pentacene. These observations, coupled with the results of neutron reflectivity study, indicate that the formation of a vertically phase-separated layer of crystalline small-molecule semiconductors allows the impurity species to remain preferentially in the adjacent polymerrich layer. Such a "zone-refinement effect" in blend semiconductors effectively removes the impurity species that are detrimental to organic electronic devices from the critical charge-transporting interface region.

Original languageEnglish
Pages (from-to)412-415
Number of pages4
JournalJournal of the American Chemical Society
Issue number3
StatePublished - Jan 26 2011

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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