Odor sensing with organic transistors
AssigneeLucent Technologies Inc.
InventorsAnanth Dodabalapur, Rahul Sarpeshkar
Life of this patent
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Abstract
A circuit includes at least one odor-sensitive organic field effect transistor (OFET) having a conduction channel whose conductivity changes in response to certain ambient odors and a feedback loop coupled between an output and an input of the circuit. The feedback loop generates a feedback signal which stabilizes the output signal of the circuit for time drift of the odor-sensitive organic transistor. In one embodiment, the OFET is an integral part of an amplifier and generates input signals to the amplifier in response to certain odors. A selectively enabled switch may be coupled between the output and the input of the amplifier circuit to provide negative feedback that tends to cancel the effect on the amplifier of time drift due to the OFET.
Claims18
A gas sensor comprising:
- an amplifier section having an input and an output and including an organic field effect transistor (OFET) sensitive to an odor, said OFET being connected to supply an input signal to said amplifier section and said OFET being connected in circuit with a first field effect transistor(FET) to form one of a common source amplifier stage and a differential amplifier stage in said amplifier section;
- and
- a low pass filter selectively coupled between the output and the input of the amplifier section to provide negative feedback that cancels drift of an output from the amplifier section.
An amplifier circuit comprising
- an amplifier;
- an odor-sensitive organic field effect transistor (OFET) being connected in said amplifier to function as a sensor and as a source of an input signal to said amplifier and said amplifier including at least one field effect transistor (FET) connected in circuit with said OFET for amplifying said input signal;
- a selectively enabled feedback loop for canceling drift in an output signal produced by the amplifier;
- a controller for applying odors to the amplifier circuit and for, during the time the odors are applied to the amplifier, disabling the feedback loop;
- and
- wherein said selectively enabled feedback loop includes a low pass filter.
An amplifier circuit comprising:
- an amplifier;
- an odor-sensitive organic field effect transistor (OFET) being connected in said amplifier to function as a sensor and as a source of an input signal;
- a selectively enabled feedback loop for canceling drift in an output signal produced by the amplifier;
- and
- wherein said OFET has a channel formed from one of the following materials:
- (a) didodecyl α-sexithiophene (DDα6T);
- (b) dioctadecyl α-sexithiophene;
- (c) copperphthallocyanine;
- (d) α-sexithiophene;
- (e) αω-dihexylsexithiophene;
- (f) poly(3-alkythiophene);
- (g) poly(3-hexylthiophene);
- (h) poly(3-dodecylthiophene);
- (i) hexadecafluorocopperphthallocyanine (F16CuPc);
- and
- (j) naphthalenetetracarboxylic diimide compounds.
A circuit comprising:
- an odor-sensitive organic transistor having an organic semiconductor channel exposed to ambient odors;
- wherein the circuit includes a differential amplifier having first and second inputs defined by the odor sensitive organic transistor and a reference transistor, respectively;
- and
- a feedback circuit to generate a feedback signal that stabilizes an output signal of the odor-sensitive organic transistor for time drift caused by changes in the ratio of the currents in the organic transistor and the reference transistor.
An amplifier circuit comprising:
- an organic field effect transistor (OFET) for sensing odors, said OFET being characterized in that it is subject to drift and threshold shift as a function of time;
- said OFET being connected in said amplifier circuit for functioning as a sensor and as a source of input signal to the amplifier circuit in response to odors;
- means for sensing the conductivity of the OFET and including a selectively enabled feedback loop for canceling the effect of drift at an output of the OFET as a function of time;
- and
- means for applying odors to the amplifier circuit and for, during the time the odors are applied to the amplifier circuit, disabling the feedback loop;
- and
- said amplifier circuit including at least one field effect transistor (FET) connected in circuit with said OFET.
Dependencies are inferred from the claim text.