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Title: Microstructural control of charge transport in organic blend thin-film transistors

Abstract

In this paper, the charge-transport processes in organic p-channel transistors based on the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT), the polymer poly(triarylamine)(PTAA) and blends thereof are investigated. In the case of blend films, lateral conductive atomic force microscopy in combination with energy filtered transmission electron microscopy are used to study the evolution of charge transport as a function of blends composition, allowing direct correlation of the film's elemental composition and morphology with hole transport. Low-temperature transport measurements reveal that optimized blend devices exhibit lower temperature dependence of hole mobility than pristine PTAA devices while also providing a narrower bandgap trap distribution than pristine diF-TES ADT devices. These combined effects increase the mean hole mobility in optimized blends to 2.4 cm 2/Vs; double the value measured for best diF-TES ADT-only devices. The bandgap trap distribution in transistors based on different diF-TES ADT:PTAA blend ratios are compared and the act of blending these semiconductors is seen to reduce the trap distribution width yet increase the average trap energy compared to pristine diF-TES ADT-based devices. In conclusion, our measurements suggest that an average trap energy of <75 meV and a trap distribution of <100 meV is needed to achieve optimum hole mobility in transistors basedmore » on diF-TES ADT:PTAA blends.« less

Authors:
 [1];  [2];  [1]
  1. Imperial College, London (United Kingdom)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1265395
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Advanced Functional Materials
Additional Journal Information:
Journal Volume: 24; Journal Issue: 38; Journal ID: ISSN 1616-301X
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; organic transistors; organic blend semiconductors; conductive AFM; charge transport; percolation

Citation Formats

Hunter, Simon, Chen, Jihua, and Anthopoulos, Thomas D. Microstructural control of charge transport in organic blend thin-film transistors. United States: N. p., 2014. Web. doi:10.1002/adfm.201401087.
Hunter, Simon, Chen, Jihua, & Anthopoulos, Thomas D. Microstructural control of charge transport in organic blend thin-film transistors. United States. doi:10.1002/adfm.201401087.
Hunter, Simon, Chen, Jihua, and Anthopoulos, Thomas D. Thu . "Microstructural control of charge transport in organic blend thin-film transistors". United States. doi:10.1002/adfm.201401087. https://www.osti.gov/servlets/purl/1265395.
@article{osti_1265395,
title = {Microstructural control of charge transport in organic blend thin-film transistors},
author = {Hunter, Simon and Chen, Jihua and Anthopoulos, Thomas D.},
abstractNote = {In this paper, the charge-transport processes in organic p-channel transistors based on the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT), the polymer poly(triarylamine)(PTAA) and blends thereof are investigated. In the case of blend films, lateral conductive atomic force microscopy in combination with energy filtered transmission electron microscopy are used to study the evolution of charge transport as a function of blends composition, allowing direct correlation of the film's elemental composition and morphology with hole transport. Low-temperature transport measurements reveal that optimized blend devices exhibit lower temperature dependence of hole mobility than pristine PTAA devices while also providing a narrower bandgap trap distribution than pristine diF-TES ADT devices. These combined effects increase the mean hole mobility in optimized blends to 2.4 cm2/Vs; double the value measured for best diF-TES ADT-only devices. The bandgap trap distribution in transistors based on different diF-TES ADT:PTAA blend ratios are compared and the act of blending these semiconductors is seen to reduce the trap distribution width yet increase the average trap energy compared to pristine diF-TES ADT-based devices. In conclusion, our measurements suggest that an average trap energy of <75 meV and a trap distribution of <100 meV is needed to achieve optimum hole mobility in transistors based on diF-TES ADT:PTAA blends.},
doi = {10.1002/adfm.201401087},
journal = {Advanced Functional Materials},
number = 38,
volume = 24,
place = {United States},
year = {Thu Jul 17 00:00:00 EDT 2014},
month = {Thu Jul 17 00:00:00 EDT 2014}
}

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Free Publicly Available Full Text
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Cited by: 27works
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  • Organic thin-film electronics have long been considered an enticing candidate in achieving high-throughput manufacturing of low-power ubiquitous electronics. However, to achieve this goal, more work is required to reduce operating voltages and develop suitable mass-manufacture techniques. Here, we demonstrate low-voltage spray-cast organic thin-film transistors based on a semiconductor blend of 2,8-difluoro- 5,11-bis (triethylsilylethynyl) anthradithiophene and poly(triarylamine). Both semiconductor and dielectric films are deposited via successive spray deposition in ambient conditions (air with 40%–60% relative humidity) without any special precautions. Despite the simplicity of the deposition method, p-channel transistors with hole mobilities of >1 cm{sup 2}/Vs are realized at −4 V operation, andmore » unipolar inverters operating at −6 V are demonstrated.« less
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