Ultrasensitive Room-Temperature Operable Gas Sensors Using p-Type Na:ZnO Nanoflowers for Diabetes Detection

Abstract

Ultrasensitive room-temperature operable gas sensors utilizing the photocatalytic activity of Na-doped p-type ZnO (Na:ZnO) nanoflowers (NFs) are demonstrated as a promising candidate for diabetes detection. The flowerlike Na:ZnO nanoparticles possessing ultrathin hierarchical nanosheets were synthesized by a facile solution route at a low processing temperature of 40 °C. It was found that the Na element acting as a p-type dopant was successfully incorporated in the ZnO lattice. On the basis of the synthesized p-type Na:ZnO NFs, room-temperature operable chemiresistive-type gas sensors were realized, activated by ultraviolet (UV) illumination. The Na:ZnO NF gas sensors exhibited high gas response (S of 3.35) and fast response time (∼18 s) and recovery time (∼63 s) to acetone gas (100 ppm, UV intensity of 5 mW cm), and furthermore, subppm level (0.2 ppm) detection was achieved at room temperature, which enables the diagnosis of various diseases including diabetes from exhaled breath.

Atomic layer deposited TiO2 ultrathin layer on Ag_ZnO nanorods for stable and efficient photocatalytic degradation of RhB

“…In addition, as reported in literature, ZnO nanomaterials can be easily obtained with 0-3 D morphologies: nanoparticles [10], nanorods [11], nanoflakes [12], and nanoflowers [13,14], among which the anisotropic structure of ZnO nanorods can facilitate the electron transportation [15]. Besides, ZnO is easier to crystallize on different supports (e.g., stainless steel mesh) with low-temperature methods [16][17][18][19].…”

Recent Developments in Printing Flexible and Wearable Sensing Electronics for Healthcare Applications

“…Conventionally, gas chromatography coupled with mass spectrometry (GC–MS) is used to determine the trace levels of VOCs in human breath; however, portable systems are desired for wearable, real-time, and continuous monitoring. The latest developments in nanoscale materials, especially the thin films of metal-oxide semiconductors (MOX), resulted in the development of miniaturized sensors that are more suitable for handheld monitoring systems [102,103]. The higher surface-to-volume ratio of nanomaterials and the porosity in the thin films were reported to be sensitive to minute trace levels (i.e., parts per billion (ppb)) of the gas analytes.…”

“…Representative MOX semiconductor materials such as SnO 2 (tin oxide), ZnO (zinc oxide), WO 3 (tungsten oxide), CuO (copper oxide) nanowires, In 2 O 3 (indium oxide), Fe 2 O 3 (ferrous oxide), etc. were used for sensing various gases in human breath [22,101,102,103]. MOX gas sensors usually require a micro-hotplate to activate the redox reactions occurring at the sensing layer [104].…”

Polyionic Liquids (PIL) Promoted Ce Doped ZnO for the Photocatalytic Degradation of Rhodamine B (RhB)

“…ZnO is a wide band gap (3.37 eV at room temperature) and can only be activated by ultraviolet . In order to fabricate novel nanomaterials with enhanced optical properties, a variety of morphologies have been investigated including nanoparticles, nanoplatelets, nanorods, nanoflowers, nanotubes, hollow spheres and so on. Among the various forms and structures of ZnO nanostructures, porous structures with high porosity, mesoporous structure and hierarchical assembly structure demonstrated good photocatalytic activity, most likely because of their high porosity and large specific surface area.…”