Organic thin-film transistor sensor arrangements

Patent metadata

Field	Value
Publication number	US-9442087-B2
Application number	US-201414537690-A
Country	US
Kind code	B2
Filing date	Nov 10, 2014
Priority date	Jul 24, 2006
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A sensor includes an organic thin-film transistor (OTFT) that operates under low voltage conditions in an aqueous environment. According to an example embodiment, an OTFT includes an organic channel that electrically connects source and drain electrodes, with a gate electrode separated from the channel by a dielectric layer. The channel, gate and dielectric layer are arranged to facilitate switching of the channel region to pass current between the source and drain electrodes, in response to a low voltage applied to the gate electrode, when the channel is exposed to an aqueous solution. The current that is passed is indicative of characteristics of the aqueous solution, and is used to characterize the same. For various implementations, the low voltage operation of the sensor facilitates such characterization with substantially no ionic conduction through an analyte in the aqueous solution.

First claim

What is claimed is:

1. A method comprising:
providing an organic transistor including a gate and including a source, a drain, and an organic semiconducting channel therebetween and with exposed portions of each of the source, drain and channel for permitting direct interaction between each of the source, drain and channel with an aqueous solution;
presenting the aqueous solution to the exposed portions;
presenting a low voltage to the gate; and
sensing, in response to the steps of presenting and to direct chemical interaction between the aqueous solution and the channel while the aqueous solution is also in direct contact with both the source and drain, characteristics of the aqueous solution based on the direct chemical interaction between the aqueous solution and the channel.

2. The method of claim 1 , wherein
sensing characteristics of the aqueous solution includes sensing a change in current flowing between the source and drain via the channel as altered by interaction between a material in the solution and the channel, and sensing a type of the material based on the change in current, and
presenting the low voltage to the gate includes presenting a voltage of less than about 2 V to the gate that biases the channel to provide the current flow between the source and drain for the sensing of the change in current flowing, and that is sufficiently low to provide about no electrolytic hydrolysis or ionic conduction between the source and drain and through the material in the solution while the change in current is detected.

3. The method of claim 1 , wherein providing the organic transistor includes providing a dielectric layer between the gate and the channel, and wherein presenting the low voltage to the gate includes presenting a voltage that is less than about 2 V to the gate and using the voltage and the dielectric layer to apply an electric field to the channel that switches the channel to a conducting state via which the source and drain are electrically coupled.

4. The method of claim 3 , wherein presenting the low voltage to the gate includes presenting a voltage that is about 1 V and using the 1 V with the dielectric layer to switch the channel to the conducting state.

5. The method of claim 1 , wherein
providing the organic transistor includes providing a dielectric layer between the channel and the gate, and providing the channel with grain boundaries that facilitate the diffusion of small molecules or ions from the solution to an interface between the channel and the dielectric layer,
presenting the aqueous solution to the exposed portions includes influencing charge transport in the channel by interacting the small molecules or ions with the channel while the low voltage is presented to the gate, thereby changing an amount of current that is passed in the channel between the source and drain.

6. An apparatus comprising:
an organic transistor including a gate and including a source, a drain, and an organic semiconducting channel therebetween and with exposed portions of each of the source, drain and channel, the source, drain and channel configured and arranged to directly interact with an aqueous solution;
means for presenting the aqueous solution in direct contact with the exposed portions of each of the channel, source and drain;
means for presenting a low voltage to the gate; and
means for sensing, in response to the steps of presenting and to direct chemical interaction between the aqueous solution and the channel while the aqueous solution is also in direct contact with both the source and drain, characteristics of the aqueous solution based on the direct chemical interaction between the aqueous solution and the channel.

7. The apparatus of claim 6 , wherein
the means for sensing is configured and arranged to sense characteristics of the aqueous solution by sensing a change in current flowing between the source and drain via the channel as altered by interaction between a material in the solution and the channel, and sensing a type of the material is based on the change in current, and
the means for presenting the low voltage to the gate is configured and arranged to present a voltage of less than about 2 V to the gate to bias the channel and to provide the current flow between the source and drain for the sensing of the change in current flowing, the voltage being sufficiently low to provide about no electrolytic hydrolysis or ionic conduction between the source and drain and through the material in the solution while the change in current is detected.

8. The apparatus of claim 6 , wherein the organic transistor includes a dielectric layer between the gate and the channel, and wherein the means for presenting the low voltage to the gate is configured and arranged to present a voltage that is less than about 2 V to the gate and use the voltage and the dielectric layer to apply an electric field to the channel that switches the channel to a conducting state via which the source and drain are electrically coupled.

9. The apparatus of claim 8 , wherein the means for presenting the low voltage to the gate is configured and arranged to present a voltage that is about 1 V to the gate and use the 1 V with the dielectric layer to switch the channel to the conducting state.

10. The apparatus of claim 6 , wherein
the organic transistor includes a dielectric layer between the channel and the gate;
the channel has grain boundaries that facilitate the diffusion of small molecules or ions from the solution to an interface between the channel and the dielectric layer; and
the means for presenting the aqueous solution to the exposed portions is configured and arranged to influence charge transport in the channel by interacting the small molecules or ions with the channel while the low voltage is presented to the gate, thereby changing an amount of current that is passed in the channel between the source and drain.

11. An apparatus comprising:
an organic semiconducting channel having a conductivity characteristic and being configured and arranged to chemically interact with material in an aqueous solution in contact with the organic semiconducting channel, and to effect a change in the conductivity characteristic via the chemical interaction;
a gate configured and arranged to apply a bias to the organic semiconducting channel;
a dielectric layer electrically arranged between the gate and the organic semiconducting channel; and
source and drain electrodes connected to opposing ends of the organic semiconducting channel, the source and drain electrodes being configured and arranged as an organic transistor with the channel, the gate and the dielectric layer to characterize the material in the solution by
responding to a low voltage at the gate by conducting current through the channel while the source and drain electrodes are in direct contact with the aqueous solution, and
providing a characterization of the material in the aqueous solution by altering the flow of the current through the channel, via the chemical interaction of the organic semiconductor with the material in the aqueous solution, while the aqueous solution is in direct contact with the source and the drain.

12. The apparatus of claim 11 , wherein the channel, gate and dielectric layer are configured and arranged to facilitate switching of the channel to electrically couple the source and drain in response to a low voltage that is less than about 2 V applied to the gate, by providing a detectable change in the current through the channel via the chemical interaction at the low voltage while providing about no electrolytic hydrolysis or ionic conduction between the source and drain through th

Assignees

• Univ Leland Stanford Junior

Inventors

• Bao Zhenan
• Roberts Mark E

Classifications

• G01N27/02 Primary

  by investigating impedance · CPC title

• H01L51/052

  Electricity · mapped topic

• H01L51/0558

  Electricity · mapped topic

• H10K10/471 Primary

  the gate dielectric comprising only organic materials · CPC title

• H10K10/484

  characterised by the channel regions · CPC title