The Multisensor Array Based on Grown-On-Chip Zinc Oxide Nanorod Network for Selective Discrimination of Alcohol Vapors at Sub-ppm Range

Abstract

We discuss the fabrication of gas-analytical multisensor arrays based on ZnO nanorods grown via a hydrothermal route directly on a multielectrode chip. The protocol to deposit the nanorods over the chip includes the primary formation of ZnO nano-clusters over the surface and secondly the oxide hydrothermal growth in a solution that facilitates the appearance of ZnO nanorods in the high aspect ratio which comprise a network. We have tested the proof-of-concept prototype of the ZnO nanorod network-based chip heated up to 400 °C versus three alcohol vapors, ethanol, isopropanol and butanol, at approx. 0.2–5 ppm concentrations when mixed with dry air. The results indicate that the developed chip is highly sensitive to these analytes with a detection limit down to the sub-ppm range. Due to the pristine differences in ZnO nanorod network density the chip yields a vector signal which enables the discrimination of various alcohols at a reasonable degree via processing by linear discriminant analysis even at a sub-ppm concentration range suitable for practical applications.

Quasi-2D Co3O4 nanoflakes as an efficient gas sensor versus alcohol VOCs

“…As the Debye length becomes comparable with the thickness of the oxide nanosheets the influence of barriers might be rather pronounced. To further evaluate the mechanism of conductivity, we have performed impedance spectroscopy applying different a.c. amplitude of bias, 0.1 V and 5 V. 73 The results are presented in Figure 5c as a dependence of imaginary part of impedance (Zim) on its real part (Zreal), or Nyquist plot, for the exemplary sensor exposed to pure air. The Z(f) spectrum recorded in the air at 0.1 V of a.c. amplitude is represented by at least two semicircles allowing us to use an equivalent circuit consisting of two RC components responsible for the influence of "bulk" and "boundary" parts 74 (Figure 6c).…”

New Insights towards High-Temperature Ethanol-Sensing Mechanism of ZnO-Based Chemiresistors

“…Certain conceptual approaches to the impedance measurement of sensors are discussed in [ 24 ]. In [ 25 ], the authors report the detection of ethanol vapours at a concentration of 0.7–5.0 ppm on ZnO nanorods at a working temperature of approximately 400 °C. The nanorods were grown via a hydrothermal route directly on a multielectrode chip.…”

Двухэтапный Синтез Структурированных Микросистем Из Наностержней Оксида Цинка С Использованием Ультразвукового Спрей-Пиролиза И Низкотемпературного Гидротермального Метода

“…В настоящее время оксид цинка в виде наностержней, синтезируемых жидкостными методами, привлекает значительный интерес для таких практических применений, как фотокатализ [1,2], чувствительные слои резистивных газовых сенсоров с термо-и фотоактивацией [3,4], а также фотовольтаика [5].…”