Abstract: A system that includes an energy device having an active region configured to generate or consume electrical energy provided by an electrical current is discussed. A current limiter is disposed between the energy device and a current collector layer. The current limiter controls the current flow between the energy device and the current collector layer. A plurality of electrochemical transistors (ECTs) are arranged in an array such that each ECT in the array provides localized current control for the energy device. Each ECT includes a gate electrode, a drain electrode, a source electrode, and a channel disposed between the drain and the source electrodes. An electrolyte electrically couples the gate electrode to the channel such that an electrical signal at the gate electrode controls electrical conductivity of the channel. The current collector layer is a shared drain or source electrode for the ECTs.

Abstract: A flexible oximeter device for measuring pulse and blood oxygen saturation in tissue includes a first array of first light emitting elements that emit red light, a second array of second light emitting elements that emit green light or near-infrared (NIR) light and an array of sensor elements arranged on at least one flexible substrate. Each sensor element is configured to detect red and green or NIR light, and to output a signal representing an amount of red or green or NIR light detected. The first and second arrays and the array of sensor elements form a plurality of interleaved measurement pixels, each pixel comprising one of the first light emitting elements and a corresponding sensor element, and one of the second light emitting elements and a different corresponding sensor element.

Abstract: A flexible oximeter device for measuring pulse and blood oxygen saturation in tissue includes a first array of first light emitting elements that emit red light, a second array of second light emitting elements that emit green light or near-infrared (NIR) light and an array of sensor elements arranged on at least one flexible substrate. Each sensor element is configured to detect red and green or NIR light, and to output a signal representing an amount of red or green or NIR light detected. The first and second arrays and the array of sensor elements form a plurality of interleaved measurement pixels, each pixel comprising one of the first light emitting elements and a corresponding sensor element, and one of the second light emitting elements and a different corresponding sensor element.

Abstract: A capacitive relative humidity sensor includes a first electrode and a second electrode, where at least the one of the electrodes is a water-permeable electrode. The electrodes act in conjunction with a water-sensitive hygroscopic dielectric material. The design enables low-cost and simple fabrication of fast-responding and stable relative humidity sensors using digital fabrication techniques.

Abstract: Methods for simultaneously forming two or more different colored material layers on a substrate. include performing surface energy patterning (SEP) to define a first, hydrophobic region and a second, hydrophilic region on the substrate, applying first and second materials on the second region, wherein the first material comprises a material having a first color, and wherein the second material comprises a material having a second color, and doctor blade coating the first and second materials simultaneously to form first and second material layers on the substrate. The methods are particularly useful for making multi-color light emitting and detecting components such as LEDs and OPDs.

Abstract: Methods for simultaneously forming two or more different colored material layers on a substrate. include performing surface energy patterning (SEP) to define a first, hydrophobic region and a second, hydrophilic region on the substrate, applying first and second materials on the second region, wherein the first material comprises a material having a first color, and wherein the second material comprises a material having a second color, and doctor blade coating the first and second materials simultaneously to form first and second material layers on the substrate. The methods are particularly useful for making multi-color light emitting and detecting components such as LEDs and OPDs.

Abstract: A system that includes an energy device having an active region configured to generate or consume electrical energy provided by an electrical current is discussed. A current limiter is disposed between the energy device and a current collector layer. The current limiter controls the current flow between the energy device and the current collector layer. A plurality of electrochemical transistors (ECTs) are arranged in an array such that each ECT in the array provides localized current control for the energy device. Each ECT includes a gate electrode, a drain electrode, a source electrode, and a channel disposed between the drain and the source electrodes. An electrolyte electrically couples the gate electrode to the channel such that an electrical signal at the gate electrode controls electrical conductivity of the channel. The current collector layer is a shared drain or source electrode for the ECTs.

Abstract: A system that includes an energy device having an active region configured to generate or consume electrical energy provided by an electrical current is discussed. A current limiter is disposed between the energy device and a current collector layer. The current limiter controls the current flow between the energy device and the current collector layer. A plurality of electrochemical transistors (ECTs) are arranged in an array such that each ECT in the array provides localized current control for the energy device. Each ECT includes a gate electrode, a drain electrode, a source electrode, and a channel disposed between the drain and the source electrodes. An electrolyte electrically couples the gate electrode to the channel such that an electrical signal at the gate electrode controls electrical conductivity of the channel. The current collector layer is a shared drain or source electrode for the ECTs.

Abstract: The following relates generally to ion sensing using organic electrochemical transistors (OECTs). In one aspect, a device comprises: an amplification portion including an OECT; a feedback portion that receives a differential voltage from the amplification portion and outputs a feedback signal; and a readout portion which receives the feedback signal and outputs an output voltage.

Abstract: A capacitive relative humidity sensor includes a first electrode and a second electrode, where at least the one of the electrodes is a water-permeable electrode. The electrodes act in conjunction with a water-sensitive hygroscopic dielectric material. The design enables low-cost and simple fabrication of fast-responding and stable relative humidity sensors using digital fabrication techniques.

Abstract: A system that includes an energy device having an active region configured to generate or consume electrical energy provided by an electrical current is discussed. A current limiter is disposed between the energy device and a current collector layer. The current limiter controls the current flow between the energy device and the current collector layer. A plurality of electrochemical transistors (ECTs) are arranged in an array such that each ECT in the array provides localized current control for the energy device. Each ECT includes a gate electrode, a drain electrode, a source electrode, and a channel disposed between the drain and the source electrodes. An electrolyte electrically couples the gate electrode to the channel such that an electrical signal at the gate electrode controls electrical conductivity of the channel. The current collector layer is a shared drain or source electrode for the ECTs.

Abstract: The following relates generally to ion sensing using organic electrochemical transistors (OECTs). In one aspect, a device comprises: an amplification portion including an OECT; a feedback portion that receives a differential voltage from the amplification portion and outputs a feedback signal; and a readout portion which receives the feedback signal and outputs an output voltage.

Abstract: Pulse oximeter devices include a first light emitting element that emits red light, a second light emitting element that emits green light or IR light; and a sensor element that detects red and green (or IR) light and that outputs signals representing detected red and green (or IR) light. The pulse oximeter device further includes a flexible substrate, wherein the first light emitting element, the second light emitting element and the sensor element are formed on the flexible substrate. The sensor element is configured to detect the emitted red and green light transmitted through tissue containing blood, and in certain aspects, the sensor element is configured to detect the emitted red and green (or IR) light reflected by tissue containing blood. A signal processing element (e.g., a processor) receives and processes the signals representing detected red and green (or IR) light output by the sensor element to produce signals representing blood oxygenation content.

Abstract: Methods for simultaneously forming two or more different colored material layers on a substrate. include performing surface energy patterning (SEP) to define a first, hydrophobic region and a second, hydrophilic region on the substrate, applying first and second materials on the second region, wherein the first material comprises a material having a first color, and wherein the second material comprises a material having a second color, and doctor blade coating the first and second materials simultaneously to form first and second material layers on the substrate. The methods are particularly useful for making multi-color light emitting and detecting components such as LEDs and OPDs.

Abstract: One embodiment provides electronic device, which can include at least two organic electrochemical transistors (OECTs). A respective OECT includes a conductive channel, a gate electrically coupled to the conductive channel via a first electrolyte, and source and drain electrodes separated from each other by the conductive channel. The electrochemical potentials of redox-couples of the at least two organic electrochemical transistors are different, thereby resulting in the at least two organic electrochemical transistors having different threshold voltages. An alternative embodiment can provide an organic electrochemical transistor (OECT). The OECT can include a conductive channel, a gate electrically coupled to the conductive channel via a first electrolyte, and source and drain electrodes separated from each other by the conductive channel. The gate can include a conductive current collector and at least one redox-couple.

Abstract: One embodiment provides electronic device, which can include at least two organic electrochemical transistors (OECTs). A respective OECT includes a conductive channel, a gate electrically coupled to the conductive channel via a first electrolyte, and source and drain electrodes separated from each other by the conductive channel. The electrochemical potentials of redox-couples of the at least two organic electrochemical transistors are different, thereby resulting in the at least two organic electrochemical transistors having different threshold voltages. An alternative embodiment can provide an organic electrochemical transistor (OECT). The OECT can include a conductive channel, a gate electrically coupled to the conductive channel via a first electrolyte, and source and drain electrodes separated from each other by the conductive channel. The gate can include a conductive current collector and at least one redox-couple.

Abstract: Pulse oximeter devices include a first light emitting element that emits red light, a second light emitting element that emits green light or IR light; and a sensor element that detects red and green (or IR) light and that outputs signals representing detected red and green (or IR) light. The pulse oximeter device further includes a flexible substrate, wherein the first light emitting element, the second light emitting element and the sensor element are formed on the flexible substrate. The sensor element is configured to detect the emitted red and green light transmitted through tissue containing blood, and in certain aspects, the sensor element is configured to detect the emitted red and green (or IR) light reflected by tissue containing blood. A signal processing element (e.g., a processor) receives and processes the signals representing detected red and green (or IR) light output by the sensor element to produce signals representing blood oxygenation content.