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May 20-21, 2019 | Vienna, Austria
Biomaterials and Nanomaterials &
Materials Physics and Materials Science
2
nd
International Conference on
Journal of Materials Science and Nanotechnology | Volume 3
Highly sensitive and selective gas sensor utilising tips pentacene based organic thin
film transistor
Amjad Al Shawi
Bangor University, UK
O
rganic sensing technology has been widely
investigated in the last few years. The low fabrication
cost, high sensitivity, short response and recovery time
allowed this type of sensors to dominate the research
activities in academia and industry. In this work, solution
processed organic thin film transistors (OTFTs) based on
6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene were
fabricated and characterized using the bottom-gate,
top-contact (B-G, T-C) configuration. After preparing
clean glass substrate, a 50nm aluminium was thermally
evaporated as the gate electrode. The insulating layer was
spin coated (2000 rpm) from a cross-linked polymethyl
methacrylate (cPMMA) 5% anisole solution by using
[1,6-bis(trichlorosilyl) hexane (C6-Si) (10μ/1ml) as a cross-
linking agent to produce 330nm layer thick. Tips-pentacene
semiconductor (2% toluene solution) was drop coasted on
the cPMMA layer as the active layer. Finally, gold electrodes
of 50nm thickness were thermally evaporated on the TIPS-
pentacene active layer to provide the drain and source.
After exposing the OTFTs to different concentrations of
ethanol vapour, the current-voltage characteristics of the
OTFT sensor and the response to different concentrations
of ethanol (from 1ppm to 8ppm) were investigated. The
output characteristics (VDS = 0 – (-60) V) with different
gate voltages (VGS= 0 – (-50) V) and different ethanol
concentration were investigated. It was found that the
drain source current in the saturation region decreases
rapidly when the OTFT was exposed to ethanol vapour
at room temperature (~25 Co). Furthermore, the transfer
characteristics with different ethanol concentrations
showed a clear shift in the threshold voltage, which
increased (from -2V to -18 V) with increasing the ethanol
concentration.
Therefore, the source drain current in the TIPS pentacene
based OTFTs can be considered as a significant parameter
to monitor chemical species and it can be used as a sensor
for chemical gases.
Speaker Biography
Amjad Al Shawi is a PhD student at the school of electronic engineering,
Bangor University, UK. He is in his third year of the PhD in the field of
organic transistors and organic memory devices. He completed his
B.Sc.and
M.Sc.study in physics from Basra University, Iraq. He also worked
as a researcher in the Polymer Research Centre at Basra University, Iraq.
e:
a.alshawi@bangor.ac.uk