title: Nanotextured organic light emitting diode based chemical sensor.
abstract: In this paper we present the design, fabrication and development of an optical, label free chemical sensor technology based on the portable "lab-on-a-chip" format. This sensor technology employs the use of nanotextured thin film surfaces packaged in a stacked vertical array format functioning as organic light emitting diodes (OLED's). The intensity of emitted light from OLED's is modulated as a function of the analyte concentration. The OLEDs were fabricated in a layer by layer configuration with an indium tin oxide anode and an aluminum cathode and TPD as a hole transport layer and AIQ3 as an electron transport layer. ITO/TPD/AlQ3/Al sandwich OLEDs were converted into sensors by converting the cathode (Al) surface into an active sensing area. The prototype sensor performance was evaluated in the detection of two aliphatic hydrocarbons-ethanol and methanol. The detection sensitivity was found to be in the lower parts per million (ppm). The limit of detection for ethanol was 1 ppm and that for methanol was 10 ppm. Chemical detection was achieved upon the comparison of turn-on voltages and the intensities of the output light from the OLED when chemical was being injected onto the cathode surface, with that of a standard OLED turn-on voltage and intensity. The modulation in these two parameters with respect to the standard was determined as a measure of detection of the two chemical species.
authors.affiliation: Department of Electrical and Computer Engineering, Portland State University, Portland, OR-97201, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Devabhaktuni
authors.forename: Shalini
authors.initials: S
authors.lastname: Prasad
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006838:Hydrocarbons / Q000032:analysis*; D056656:Lab-On-A-Chip Devices; D008029:Lighting / Q000295:instrumentation*; D036103:Nanotechnology / Q000295:instrumentation*; D010783:Photometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity; D014159:Transducers
chemical_list: D006838:Hydrocarbons