This Small Business Innovation Research (SBIR) Phase I project aims to develop a next-generation microsensor for dissolved oxygen (DO) in water. DO sensors are a primary tool for gauging the quality of both fresh water (rivers, lakes, reservoirs) and the oceans; for monitoring the various processes in waste water treatment plants; and, for monitoring fermentation processes in the food and beverage industries. Unfortunately, electrochemical sensors are slow (response time >1 min), short-lived (a few days), and expensive (~$500). The proposed DO sensor is based on a new platform of structurally integrated photoluminescence (PL)-based chemical and biological sensors. In this platform, the pulsed light source that excites the PL is an array of individually addressable ~100 um2 to ~1 cm2 organic light-emitting device (OLED) pixels. The small pixels will eventually enable development of microsensor arrays. The ~0.5 um-thick pixel array and ~1 um-thick sensor film will be fabricated on opposite sides of a glass or plastic substrate, or on two substrates attached back-to-back. The Si photodiode will be "behind" the OLED array, monitoring the PL passing between the OLED pixels. This uniquely simple structurally integrated platform should ultimately yield multianalyte chemical and biological microsensor arrays for a wide variety of agents.
If successful the proposed device will be uniquely simple, initially palm-size and eventually microsize, autonomous, fast (~1 sec response), miserly on power consumption, and inexpensive (ultimately with an essentially disposable OLED/sensor film module). It will operate in the PL-lifetime mode, eliminating the need for frequent calibration. It will consequently replace the short-lived electrochemical sensors and the expensive PL-based DO sensors that currently serve the diverse markets listed above. The proposed development of the DO microsensor will demonstrate the viability of the new OLED-based sensor platform, leading the way towards the development of multianalyte chemical and biological microsensor arrays for gas and liquid phases. This development will enhance scientific and technological needs in the field of sensor technology by addressing current issues of sensor size, cost, analyte sampling, and field deployability.
