Flexible nanostructured TiO2-based gas and UV sensors: a review

Abstract

Flexible sensors have been attracting an ever-growing attention over the last years due to their outstanding characteristics, that include their lightweight and cost-effective characteristics, high stretchability, biocompatibility, and conformability. Moreover, the pursue of such devices has exponentially raised, with the IoT (Internet of Things) technology and the integration of several kinds of sensor devices that allow exchanging information on the internet, as well as remotely operating devices and collecting data. In fact, IoT is bringing sensor usage to a new level, where gas and ultraviolet (UV) sensors are largely integrated, guaranteeing the well-being and safety of people, with the immediate detection and response to changes in an environment. Gas and UV sensors based on titanium dioxide (TiO2) have been largely reported, where numerous efforts have been devoted to improving its sensing performance, especially when employing TiO2 at the nanoscale. TiO2 has the advantage of being chemical stable, non-toxic, inexpensive, and compatible with low-cost wet-chemical synthesis routes. This review outlines the current state of flexible gas and UV sensor technologies having TiO2 as the sensing layer and the impact of this nanostructured material on the field.

Nanostructured thin films of TiO2 tailored by anodization

“…3.37 ± 0.02 eV, for the 3 to 9 min samples, is suitable for HPSC applications[41]. These values are higher than in bulk TiO 2 (3.2 eV[13,40,44]), but within the expected range for TNS (∼3.3-3.43 eV[2,[45][46][47][48][49][50]). Table…”

Plasmons Enhancing Sub-Bandgap Photoconductivity in TiO2 Nanoparticles Film

“…Due to their potential for clean and sustainable technology, light harvesting materials and strategies have gained considerable attention in the last couple of years. TiO 2 is extensively investigated due to its direct wide bandgap and tunable electrical and optical properties that originate from its intragap energy levels related to inherited surface defects and oxygen vacancies. , Such unique properties enable TiO 2 to be highly desirable in light harvesting applications such as photocatalysis, photovoltaics, photodetection, and photoelectrochemical sensing . Due to its hypotoxicity and abundance, developing efficient photoconductivity of TiO 2 in the visible band will significantly impact the environment and device production cost .…”

Green Synthesis of TiO2 Using Impatiens rothii Hook.f. Leaf Extract for Efficient Removal of Methylene Blue Dye

“…21,23 There are three crystallographic forms of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), and brookite (orthorhombic). 24,25 In general, TiO 2 is considered as an ecologically friendly and has been used in various industrial applications including gas sensors, 26 corrosion protection, 27 white pigment, 28 dye-sensitized solar cells, 29 remediation of the environment, 30 hydrogen gas production, 31 providing high dielectric constant and high electrical resistance, 32 and reduction of carbon dioxide. 33 Titanium dioxide NPs can be synthesized using a variety of methods, including sol−gel, sono-chemical, microwave-assisted, 34 deposition, hydro/solvothermal, and oxidation methods.…”

“…Due to its numerous benefits, such as great photocatalytic ability, high oxidizing power, low toxicity and biocompatibility, excellent chemical stability, and ease of accessibility, TiO 2 is one of the best materials for photocatalytic processes. , There are three crystallographic forms of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), and brookite (orthorhombic). , In general, TiO 2 is considered as an ecologically friendly and has been used in various industrial applications including gas sensors, corrosion protection, white pigment, dye-sensitized solar cells, remediation of the environment, hydrogen gas production, providing high dielectric constant and high electrical resistance, and reduction of carbon dioxide …”