12 research outputs found
H<sub>2</sub>S and NH<sub>3</sub> Detection with Langmuir-Schaefer Monolayer Organic Field-Effect Transistors
In this work gas sensing properties of Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) have been investigated. The monolayer has been deposited using Langmuir-Schaefer method, which results in a uniform low-defect monolayer with excellent electrical performance, hole mobility up to 7 × 10−2 cm2 V−1 s−1, the threshold voltage around 0 V and on-off ratio of 104. Developed sensors demonstrate a long-term stability of a half-year storage under ambient conditions. Preliminary investigations demonstrated that the LS OFETs give instantaneous response on ammonia and hydrogen sulfide at low concentrations. The results reported open new perspectives for the OFET-based gas-sensing technology
Applying of C8-BTBT-Based EGOFETs at Different pH Values of the Electrolyte
Electrolyte-gated organic field-effect transistors (EGOFETs) is a popular platform for numerous sensing and biosensing applications in aqueous media. In this work, the variation of electrical characteristics of EGOFETs based on small-molecule organic semiconductor C8-BTBT and polystyrene blend in water solutions at different pH values was investigated. A positive shift of the threshold voltage with near-Nernstian pH sensitivity was demonstrated in the pH range from 4.9 to 2.8, while no measurable pH dependence in the range from 4.9 to 8.6 pH was registered. These results indicate chemical doping of the molecules of organic semiconductors by protons from the electrolyte in the acidic region. In order to check the applicability of the EGOFETs in a flow mode, a flow chamber was designed and assembled. The preliminary results obtained in the flow mode measurements showed a fast response to pH variation
Applying of C8-BTBT-Based EGOFETs at Different pH Values of the Electrolyte
Electrolyte-gated organic field-effect transistors (EGOFETs) is a popular platform for numerous sensing and biosensing applications in aqueous media. In this work, the variation of electrical characteristics of EGOFETs based on small-molecule organic semiconductor C8-BTBT and polystyrene blend in water solutions at different pH values was investigated. A positive shift of the threshold voltage with near-Nernstian pH sensitivity was demonstrated in the pH range from 4.9 to 2.8, while no measurable pH dependence in the range from 4.9 to 8.6 pH was registered. These results indicate chemical doping of the molecules of organic semiconductors by protons from the electrolyte in the acidic region. In order to check the applicability of the EGOFETs in a flow mode, a flow chamber was designed and assembled. The preliminary results obtained in the flow mode measurements showed a fast response to pH variation
Quantitative Detection of the Influenza a Virus by an EGOFET-Based Portable Device
Elaboration of biosensors on the base of organic transistors with embedded biomolecules which can operate in an aqueous environment is of paramount importance. Electrolyte-gated organic field-effect transistors demonstrate high sensitivity in detection of various analytes. In this paper, we demonstrated the possibility of quantitative fast specific determination of virus particles by an aptasensor based on EGOFET. The sensitivity and selectivity of the devices were examined with the influenza A virus as well as with control bioliquids like influenza B, Newcastle disease viruses or allantoic fluid with different dilutions. The influence of the semiconducting layer thickness on EGOFETs sensory properties is discussed. The fabrication of a multi-flow cell that simultaneously registers the responses from several devices on the same substrate and the creation of a multi-sensor flow device are reported. The responses of the elaborated bioelectronic platform to the influenza A virus obtained with application of the portable multi-flow mode are well correlated with the responses obtained in the laboratory stationary mode
Polymer Surface Engineering for Efficient Printing of Highly Conductive Metal Nanoparticle Inks
An approach to polymer surface modification
using self-assembled
layers (SALs) of functional alkoxysilanes has been developed in order
to improve the printability of silver nanoparticle inks and enhance
adhesion between the metal conducting layer and the flexible polymer
substrate. The SALs have been fully characterized by AFM, XPS, and
WCA, and the resulting printability, adhesion, and electrical conductivity
of the screen-printed metal contacts have been estimated by cross-cut
tape test and 4-point probe measurements. It was shown that (3-mercaptopropyl)Âtrimethoxysilane
SALs enable significant adhesion improvements for both aqueous- and
organic-based silver inks, approaching nearly 100% for PEN and PDMS
substrates while exhibiting relatively low sheet resistance up to
0.1 Ω/sq. It was demonstrated that SALs containing functional
−SH or −NH<sub>2</sub> end groups offer the opportunity
to increase the affinity of the polymer substrates to silver inks
and thus to achieve efficient patterning of highly conductive structures
on flexible and stretchable substrates
Easily Processable Highly Ordered Langmuir-Blodgett Films of Quaterthiophene Disiloxane Dimer for Monolayer Organic Field-Effect Transistors
Self-assembly of highly soluble water-stable
tetramethyldisiloxane-based
dimer of α,α′-dialkylquaterthiophene on the water–air
interface was investigated by Langmuir, grazing incidence X-ray diffraction,
and X-ray reflectivity techniques. The conditions for formation of
very homogeneous crystalline monolayer Langmuir-Blodgett (LB) films
of the oligomer were found. Monolayer organic field-effect transistors
(OFETs) based on these LB films as a semiconducting layer showed hole
mobilities up to 3 × 10<sup>–3</sup> cm<sup>2</sup>/(V
s), on–off ratio of 10<sup>5</sup>, small hysteresis, and high
long-term stability. The electrical performance of the LB films studied
is close to that for the same material in the bulk or in the monolayer
OFETs prepared from water vapor sensitive chlorosilyl derivatives
of quaterthiophene by self-assembling from solution. These findings
show high potential of disiloxane-based LB films in monolayer OFETs
for large-area organic electronics
Luminescent Organic Semiconducting Langmuir Monolayers
In
recent years, monolayer organic field-effect devices such as transistors
and sensors have demonstrated their high potential. In contrast, monolayer
electroluminescent organic field-effect devices are still in their
infancy. One of the key challenges here is to create an organic material
that self-organizes in a monolayer and combines efficient charge transport
with luminescence. Herein, we report a novel organosilicon derivative
of oligothiophene–phenylene dimer <b>D2-Und-PTTP-TMS</b> (D2, tetramethyldisiloxane; Und, undecylenic spacer; P, 1,4-phenylene;
T, 2,5-thiophene; TMS, trimethylsilyl) that meets these requirements.
The self-assembled Langmuir monolayers of the dimer were investigated
by steady-state and time-resolved photoluminescence spectroscopy,
atomic force microscopy, X-ray reflectometry, and grazing-incidence
X-ray diffraction, and their semiconducting properties were evaluated
in organic field-effect transistors. We found that the best uniform,
fully covered, highly ordered monolayers were semiconducting. Thus,
the ordered two-dimensional (2D) packing of conjugated organic molecules
in the semiconducting Langmuir monolayer is compatible with its high-yield
luminescence, so that 2D molecular aggregation per se does not preclude
highly luminescent properties. Our findings pave the way to the rational
design of functional materials for monolayer organic light-emitting
transistors and other optoelectronic devices