Affordable Access

Publisher Website

Novel fused-LEDs devices as optical sensors for colorimetric analysis

Authors
Journal
Talanta
0039-9140
Publisher
Elsevier
Publication Date
Volume
63
Issue
1
Identifiers
DOI: 10.1016/j.talanta.2003.10.034
Keywords
  • Fused-Leds
  • Optical Sensor
  • Ph Sensing
  • Reflectance Measurements
  • Colorimetric Analysis
  • Acidochromic Dyes
  • Evanescent Wave
Disciplines
  • Physics

Abstract

Abstract The development of a novel, low power optical sensing platform based on light emitting diodes (LEDs) is described. The sensor is constructed from a pair of LEDs fused together at an angle where one LED functions as the light source and the other LED is reverse biased to function as a light detector. Sensor function is based on the level of light received by the detector diode, which varies with the reflectance of the interface between the device and its environment, or the chemochromic membrane that covers the device. A simple microprocessor circuit is used to measure the time taken for the photon-induced current to discharge the detector LED from an initial 5 V (logic 1) to 1.7 V (logic zero). This sensing device has been successfully used for colour and colour-based pH measurements and offers extremely high sensitivity, enabling detection down to the sub micro molar level of dyes.

There are no comments yet on this publication. Be the first to share your thoughts.