In plane optical sensor based on organic electronic devices (original) (raw)

Organic Multi-Channel Optoelectronic Sensors for Wearable Health Monitoring

IEEE Access

Recent progress in printed optoelectronics and their integration in wearable sensors have created new avenues for research in reflectance photoplethysmography (PPG) and oximetry. The reflectionmode sensor, which consists of light emitters and detectors, is a vital component of reflectance oximeters. Here, we report a systematic study of the reflectance oximeter sensor design in terms of component geometry, light emitter and detector spacing, and the use of an optical barrier between the emitter and the detector to maximize sensor performance. Printed red and near-infrared (NIR) organic light-emitting diodes (OLEDs) and organic photodiodes (OPDs) are used to design three sensor geometries: (1) Rectangular geometry, where square OLEDs are placed at each side of the OPD; (2) Bracket geometry, where the OLEDs are shaped as brackets and placed around the square OPD; (3) Circular geometry, where the OLEDs are shaped as block arcs and placed around the circular OPD. Utilizing the bracket geometry, we observe 39.7% and 18.2% improvement in PPG signal magnitude in the red and NIR channels compared to the rectangular geometry, respectively. Using the circular geometry, we observe 48.6% and 9.2% improvements in the red and NIR channels compared to the rectangular geometry. Furthermore, a wearable two-channel PPG sensor is utilized to add redundancy to the measurement. Finally, inverse-variance weighting and template matching algorithms are implemented to improve the detection of heart rate from the multi-channel PPG signals.

Optical sensor array platform based on polymer electronic devices

Electro-Optical Remote Sensing, Detection, and Photonic Technologies and Their Applications, 2007

Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

Organic Light-Emitting Diode Sensing Platform: Challenges and Solutions

Advanced Functional Materials, 2011

electronics-based (bio)chemical sensing and biotechnology applications. As examples, luminescent conjugated polymers have been used to gain insight into biology and pathology of protein aggregation diseases, and for designing electrochemical switches and ion pumps for cell biology studies. [ 3 , 4 ] Organic thin fi lm transistors (OTFTs) were implemented to develop cost-effective and label-free DNA or protein sensor chips, and organic light-emitting diodes (OLEDs) have been evaluated as excitation sources in photo luminescence (PL)-based sensing of analytes such as oxygen, ethanol, glucose, lactate, and cholesterol. [ 1 , 6-13 ] Other examples of the use of OLEDs (including polymer LEDs (PLEDs)) in sensing applications include an integrated PL-based oxygen and pH sensor, utilizing an OLED as the light source and an organic photodetector (PD); [ 13 -16 ] two polarizers were used for separating the PL and the OLED's electroluminescence (EL). OLEDs were used also for fl uorescence detection of proteins and PLEDs were used as an integrated excitation source for microfabricated capillary electrophoresis. The use of PLEDs for monitoring biomolecules labeled with fl uorescent dyes by monitoring shifts in the PLED's EL and a surface plasmon resonance sensor utilizing an OLED and a metallic sensing layer were also reported. A nanotextured OLED-based chemical sensor for label-free detection of methanol and ethanol was demonstrated. The detection was based on monitoring analyte-induced changes in the OLED turn-on voltage and EL intensity. In another example, a refractometer with an integrated OLED light source and dual organic PDs (OPDs) were used for sensitive analyte detection by monitoring the change in light fl ux from the OLED to the PD that resulted from changes in refractive index of the analyte solution relative to a reference solution. Good detection sensitivities are often obtained using OTFTand OLED-based sensors, and the issue of the long-term stability that affects the organic devices is often less important in their sensing platforms, as the sensing probes are often shorter lived than the OLEDs. Moreover, as the cost of OTFTs and OLEDs is expected to drop, they are promising for use in disposable sensors.

All-organic optoelectronic sensor for pulse oximetry

Pulse oximetry is a ubiquitous non-invasive medical sensing method for measuring pulse rate and arterial blood oxygenation. Conventional pulse oximeters use expensive optoelectronic components that restrict sensing locations to finger tips or ear lobes due to their rigid form and area-scaling complexity. In this work, we report a pulse oximeter sensor based on organic materials, which are compatible with flexible substrates. Green (532 nm) and red (626 nm) organic light-emitting diodes (OLEDs) are used with an organic photodiode (OPD) sensitive at the aforementioned wavelengths. The sensor’s active layers are deposited from solution-processed materials via spin-coating and printing techniques. The all-organic optoelectronic oximeter sensor is interfaced with conventional electronics at 1 kHz and the acquired pulse rate and oxygenation are calibrated and compared with a commercially available oximeter. The organic sensor accurately measures pulse rate and oxygenation with errors of 1% and 2%, respectively.

Multianalyte sensor array based on an organic light emitting diode platform

Sensors and Actuators B: Chemical, 2008

A compact photoluminescence (PL)-based sensor array, utilizing pulsed organic light emitting diode (OLED) pixels as the excitation sources, for sequential or simultaneous detection of multiple analytes in a single sample, is described. The utility and potential advantages of the structurally integrated OLEDbased platform for multianalyte detection are demonstrated for oxygen, glucose, lactate, and ethanol. The detection of glucose, lactate, and ethanol is based on monitoring the concentration of dissolved oxygen (DO) at the completion of the enzymatic oxidation reactions of these analytes in sealed cells. The monitoring in sealed cells and the ready access of the enzyme, when in solution, to the analyte enable a limit of detection of ∼0.02 mM, which is better than that obtained with enzymes embedded in sol-gel films. The DO concentration is determined via its effect on the PL decay time of the oxygen-sensitive dye Pt octaethylporphyrin embedded in a polystyrene film. A modified Stern-Volmer equation is derived to generate a linear calibration. The 2 mm × 2 mm OLED pixels and the sensor films are fabricated on glass substrates that are attached back-to-back, generating a compact module devoid of any optical couplers. Two individually addressable OLED pixels are associated with the detection of each analyte. This configuration enables consecutive detection of all analytes within a few minutes utilizing a single photodetector (PD). Simultaneous detection is achieved by using an array of small-size Si photodiode PDs compatible with the OLED pixel array. The OLED-based sensing array is unique in its ease of fabrication and integration with the sensing component, while its performance attributes are comparable to those obtained for detection of a single analyte using any excitation source.

A flexible organic reflectance oximeter array

Proceedings of the National Academy of Sciences

Transmission-mode pulse oximetry, the optical method for determining oxygen saturation in blood, is limited to only tissues that can be transilluminated, such as the earlobes and the fingers. The existing sensor configuration provides only single-point measurements, lacking 2D oxygenation mapping capability. Here, we demonstrate a flexible and printed sensor array composed of organic light-emitting diodes and organic photodiodes, which senses reflected light from tissue to determine the oxygen saturation. We use the reflectance oximeter array beyond the conventional sensing locations. The sensor is implemented to measure oxygen saturation on the forehead with 1.1% mean error and to create 2D oxygenation maps of adult forearms under pressure-cuff–induced ischemia. In addition, we present mathematical models to determine oxygenation in the presence and absence of a pulsatile arterial blood signal. The mechanical flexibility, 2D oxygenation mapping capability, and the ability to place ...

An optical sensor array on a flexible substrate with integrated organic opto-electric devices

Procedia Engineering, 2010

A new optical integrated sensor array for multi-analyte sensing applications is presented. The sensor platform consists of monolithically integrated luminescent sensor spots together with ring-shaped organic photo-detector on one substrate and an assembled organic light emitting diode. The sensing layer is screen printed onto the flexible polymeric (PET) substrate. All production steps can be adapted to mass production. Due to the sensing geometry the array does not require to integrate filters to discriminate between excitation light and emitted luminescence of the sensing a layer. The sensor platform is suitable for the parallel detection of multiple parameters. Sensing schemes for the analytical parameters oxygen, carbon dioxide, temperature and ammonia are presented. The response of the sensor device when applied to different atmospheres showed good performance emphasizing the universal and simple use of the sensor platform.

Integrated organic light-emitting device/fluorescence-based chemical sensors

Applied Physics Letters, 2002

A fluorescent chemical sensor platform, integrating an organic light-emitting device ͑OLED͒ light-source with a fluorescent probe, is demonstrated for a subsecond-fast oxygen sensor. The integration results in strong light coupling and negligible heating of the sensor film or analyte. The potential in vivo operation of compact, stand-alone, battery-powered, OLED-based miniaturized sensor arrays for chemical and biological applications is discussed.

Performance of white organic light-emitting diode for portable optical biosensor

Sensors and Actuators B: Chemical, 2016

A white organic light-emitting diode (OLED) with enhanced sensitivity has been demonstrated as a novel light source in a portable surface plasmon resonance (SPR) optical biosensor. A disposable broad-spectral OLED was employed on the leg side of isosceles trapezoid prism for a fixed angle of incident light. Bimetallic Au/Ag composition layers were used as sensing layers and their composition evaluated such that the wavelength resonance occurred at the peak of the light spectrum. The SPR signal detection applied differential intensities at two reference wavelengths. We show that the integration of a white-spectral OLED on an SPR sensor improved the sensor's sensitivity by ~19.29% compared to an SPR sensor system using a green OLED as a bimetallic Ag/Au sensing layer. The limit of detection (LOD) of 2.4 × 10-6 refractive index units (RIU) has been established in the range of refractive index samples (∆n) around 3.6 × 10-3 RIU. This optical sensor demonstrated the capability of real-time monitoring, self-assembled monolayer (SAM) activation, antibody immobilization, and biomolecular interaction detection of immunoglobulin G (IgG) protein with a detection limit around 40.3 pg/mL.