Highly Sensitive InO_x Ozone Sensing Films on Flexible Substrates

Abstract

InOxthin films with a thickness of the order of 100 nm were grown by dc magnetron sputtering on glass, Si and flexible (PET) substrates. The electrical conductivity ofInOxthin films exhibited a change of two orders of magnitude during photoreduction with ultraviolet light and subsequent oxidation in ozone concentrations from 2370 to 15 ppb, at room temperature. Optical transparency of over 85% for all substrates was maintained. Film structural and ozone sensing properties were analyzed. Surface morphology investigations carried out by SEM for films on PET substrates showed extended surface cracking for bending angles beyond40∘. Optimization of growth conditions has led to films with extremely low detection levels for ozone down to 15 ppb at room temperature, demonstrating the wide prospective of utilizing these metal oxides as gas sensors on flexible substrates for a variety of automotive and air-conditioning applications.

Catalyst‐Free Vapor‐Phase Method for Direct Integration of Gas Sensing Nanostructures with Polymeric Transducing Platforms

“…Results presented in Figure 6 show a direct dependence of the sensing response to relatively low hydrogen concentrations (10,25, and 50 ppm), with polymer-and silicon-based microsensors showing good reproducibility of the sensor response to each concentration (standard errors below ∼1%).…”

“…Most of the literature reporting the direct integration of MOX nanostructures on flexible transducing platforms has been based on hydrothermal processes [7,8], and recently a direct two-step method based on thermal oxidation of a metal layer has been also proposed [9,10]. Overall, zinc oxide nanostructures have attracted much attention, particularly for direct integration approaches [7][8][9][10]22], whereas materials such as tin oxide, tungsten oxide, and indium oxide have been less used, with only few works reporting the use of these materials as thick or thin films integrated by wet transfer ( (InO ) [25] method. Similarly, most of the works on carbon nanofibers [26] and carbon nanotubes [27][28][29] report the integration of these materials using post transfer methods.…”

In2O3- and SnO2-Based Thin Film Ozone Sensors: Fundamentals

“…At present, there have been attempts to design SnO 2 -and In 2 O 3 -based ozone sensors for operation at room temperature (RT) [141,[163][164][165][166][167]. This type of ozone sensor has recently attracted great interest due to its advantages, such as low energy consumption and the possibilities of integration into plastic packages and portable devices [168]. However, one should note that such sensors usually have very low sensitivity, slow response, poor recovery features, and high sensitivity to air humidity.…”

Characterization and Gas-sensing Performance of Spray Pyrolysed In2O3Thin Films: Substrate Temperature Effect

“…Moreover, among them, indium oxide (In 2 O 3 ) thin film is one of the most significant TCO materials. It finds its usage in diverse fields like: photovoltaic devices [1] transparent windows in liquid crystal displays [2] gas sensors [3][4][5] antireflection coatings [6] electro chromic devices [7] and solar cells [8]. Various investigations have been carried out on their growth conditions.…”