In Situ Localized Growth of Ordered Metal Oxide Hollow Sphere Array on Microheater Platform for Sensitive, Ultra-Fast Gas Sensing

Abstract

A simple and versatile strategy is presented for the localized on-chip synthesis of an ordered metal oxide hollow sphere array directly on a low power microheater platform to form a closely integrated miniaturized gas sensor. Selective microheater surface modification through fluorinated monolayer self-assembly and its subsequent microheater-induced thermal decomposition enables the position-controlled deposition of an ordered two-dimensional colloidal sphere array, which serves as a sacrificial template for metal oxide growth via homogeneous chemical precipitation; this strategy ensures control in both the morphology and placement of the sensing material on only the active heated area of the microheater platform, providing a major advantage over other methods of presynthesized nanomaterial integration via suspension coating or printing. A fabricated tin oxide hollow sphere-based sensor shows high sensitivity (6.5 ppb detection limit) and selectivity toward formaldehyde, and extremely fast response (1.8 s) and recovery (5.4 s) times. This flexible and scalable method can be used to fabricate high performance miniaturized gas sensors with a variety of hollow nanostructured metal oxides for a range of applications, including combining multiple metal oxides for superior sensitivity and tunable selectivity.

Gas sensors using ordered macroporous oxide nanostructures

“…12 Meanwhile, it is indicated that it becomes easier for gas molecules to access thin nanobridges in ordered nanostructures, which facilitates the sensing process. [82][83][84] The results of both 2D IO structures and 2D hollow hemispheres clearly reveal that the 2DOM nanostructures are promising nanoarchitectures to simultaneously achieve high and rapid response. In addition, the ordered frame matrix would be robust in tolerating the compressive and tensile stresses experienced during the heating/cooling operations due to the more uniform force distribution in ordered porous lms, which can yield higher sensing stability.…”

Simulation & modelling of dilute solutions in drop-on-demand inkjet printing: a review

“…One of the most advantages of "CIJ" is a lower probability of nozzle obstruction due to the working of jetting system at all time. The major disadvantages of CIJ systems are the problem in sizes controlling, generating satellite, and splattering of the droplets on the target [9,10]. In DOD, droplets are formed alternatively by the piezoelectric properties in response to discontinued pulses and pressures, respectively.…”

Growth mechanism and electrochemical properties of hierarchical hollow SnO2 microspheres with a “chestnut” morphology

“…For example, HHMSs have been frequently investigated as nano-reactors and drug-delivery carriers, in electromagnetic wave absorption, 3,4 as well as in photocatalysis 5 and as active compounds in gas sensors 6 and in photovoltaic devices. [7][8][9] In recent years, the focus on HHMSs has shifted to their use as anode materials in lithium ion batteries (LIBs) and, recently, sodium-ion batteries (SIBs).…”