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Title: Change in Electronic States in the Accumulation Layer at Interfaces in a Poly(3-hexylthiophene) Field-Effect Transistor and the Impact of Encapsulation

Abstract

The electrical properties of organic field-effect transistors (OFETs) are largely determined by the accumulation layer that extends only a few molecular layers away from the gate dielectric/organic semiconductor interface. To understand degradation processes that occur within the device structure under ambient conditions, it is thus essential to probe the interface using an architecture that minimizes the effects of bulk transport of contaminating species through upper layers of material in a thick film device. Using FETs designed with multiple voltage probes along the conducting channel and an ultrathin film of the active material, we found that the charge carrier density and the FET mobility decrease, and further, the contact and channel properties are strongly correlated. FET devices prepared with an ultrathin film of P3HT become significantly contact limited in air due to a hole diffusion barrier near the drain electrode. Encapsulation of the device with a layered organic/inorganic barrier material consisting of parylene and Al₂O₃ appreciably retarded diffusion of molecular species from ambient air into P3HT.

Authors:
 [1];  [1];  [1];  [1]
  1. Georgia Institute of Technology, Atlanta, GA (United States)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC); Center for Interface Science: Solar Electric Materials (CISSEM)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1065635
DOE Contract Number:  
SC0001084
Resource Type:
Journal Article
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 3(9); Journal Issue: 9; Related Information: CISSEM partners with the University of Arizona (lead); Georgia Institute of Technology; National Renewable Energy Laboratory; Princeton University; University of Washington; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; solar (photovoltaic), electrodes - solar, charge transport, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)

Citation Formats

Park, Byoungnam, Kim, Y. J., Graham, Samuel, and Reichmanis, Elsa. Change in Electronic States in the Accumulation Layer at Interfaces in a Poly(3-hexylthiophene) Field-Effect Transistor and the Impact of Encapsulation. United States: N. p., 2011. Web. doi:10.1021/am200760m.
Park, Byoungnam, Kim, Y. J., Graham, Samuel, & Reichmanis, Elsa. Change in Electronic States in the Accumulation Layer at Interfaces in a Poly(3-hexylthiophene) Field-Effect Transistor and the Impact of Encapsulation. United States. doi:10.1021/am200760m.
Park, Byoungnam, Kim, Y. J., Graham, Samuel, and Reichmanis, Elsa. Wed . "Change in Electronic States in the Accumulation Layer at Interfaces in a Poly(3-hexylthiophene) Field-Effect Transistor and the Impact of Encapsulation". United States. doi:10.1021/am200760m.
@article{osti_1065635,
title = {Change in Electronic States in the Accumulation Layer at Interfaces in a Poly(3-hexylthiophene) Field-Effect Transistor and the Impact of Encapsulation},
author = {Park, Byoungnam and Kim, Y. J. and Graham, Samuel and Reichmanis, Elsa},
abstractNote = {The electrical properties of organic field-effect transistors (OFETs) are largely determined by the accumulation layer that extends only a few molecular layers away from the gate dielectric/organic semiconductor interface. To understand degradation processes that occur within the device structure under ambient conditions, it is thus essential to probe the interface using an architecture that minimizes the effects of bulk transport of contaminating species through upper layers of material in a thick film device. Using FETs designed with multiple voltage probes along the conducting channel and an ultrathin film of the active material, we found that the charge carrier density and the FET mobility decrease, and further, the contact and channel properties are strongly correlated. FET devices prepared with an ultrathin film of P3HT become significantly contact limited in air due to a hole diffusion barrier near the drain electrode. Encapsulation of the device with a layered organic/inorganic barrier material consisting of parylene and Al₂O₃ appreciably retarded diffusion of molecular species from ambient air into P3HT.},
doi = {10.1021/am200760m},
journal = {ACS Applied Materials and Interfaces},
issn = {1944-8244},
number = 9,
volume = 3(9),
place = {United States},
year = {2011},
month = {9}
}