Hierarchical ZnO Nanowires-loaded Sb-doped SnO2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules

Abstract

We propose a novel synthetic route by combining imprinting transfer of a Sb-doped SnO2 (ATO)-ZnO composite micrograting pattern (MP), i.e., microstrip lines, on a sensor substrate and subsequent hydrothermal growth of ZnO nanowires (NWs) for producing a hierarchical ZnO NW-loaded ATO-ZnO MP as an improved chemo-resistive sensing layer. Here, ATO-ZnO MP structure with 3-μm line width, 9-μm pitch, and 6-μm height was fabricated by direct transfer of mixed ATO and ZnO nanoparticle (NP)-dispersed resists, which are pre-patterned on a polydimethylsiloxane (PDMS) mold. ZnO NWs with an average diameter of less than 50 nm and a height of 250 nm were quasi-vertically grown on the ATO-ZnO MP, leading to markedly enhanced surface area and heterojunction composites between each ATO NP, ZnO NP, and ZnO NW. A ZnO NW-loaded MP sensor with a relative ratio of 1:9 between ATO and ZnO (1:9 ATO-ZnO), exhibited highly sensitive and selective acetone sensing performance with 2.84-fold higher response (Rair/Rgas = 12.8) compared to that (Rair/Rgas = 4.5) of pristine 1:9 ATO-ZnO MP sensor at 5 ppm. Our results demonstrate the processing advantages of direct imprinting-assisted hydrothermal growth for large-scale homogeneous coating of hierarchical oxide layers, particularly for applications in highly sensitive and selective chemical sensors.

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

“…Other than porous nanostructures, hierarchical nanostructures synthesized by either hydrothermal or thermal oxidation tactics were effectively applied in acetone detection. Hierarchical nanostructures of ZnO NWs-loaded Sb-doped SnO 2 -ZnO, 3D flower-like ZnO, and Au NPs-SnO 2 NTs seems to be impressive in the selective detection of acetone at operating temperatures ≥ 200 °C as presented in Table 1 [ 138 , 139 , 140 ]. Wherein, Wang et al described the direct transformation of SnS 2 NShs to hierarchical porous SnO 2 NTs via thermal oxidation, which evinced a better selectivity upon Au NPs decoration at 200 °C with a LOD of 0.445 ppm, thereby stated as an exceptional candidate in acetone sensing [ 140 ].…”

“…NTs seems to be impressive in the selective detection of acetone at operating temperatures ≥ 200 • C as presented in Table 1[138][139][140]. Wherein, Wang et al…”

Investigation of Strain Effects on Photoelectrochemical Performance of Flexible ZnO Electrodes

“…Among these metal oxides, ZnO perfectly matches with the desired properties of optoelectronics due to its higher electron mobility compared to the other metal oxides, excellent stability, and large exciton binding energy (60 meV) 13,14 . Hence, it has been used in several optoelectronic application areas including light-emitting diodes, panel displays, sensors 15 , photodetectors 16 , piezoelectrical applications 17 , and solar cells 18 . A variety of synthesis techniques have been employed for the formation of ZnO nanostructures 19–22 .…”

Aligned hierarchical Ag/ZnO nano-heterostructure arrays via electrohydrodynamic nanowire template for enhanced gas-sensing properties

“…Semiconducting metal oxides, especially ZnO, have been commonly used as the active sensing materials for gas sensors due to their fast response, short response-recovery time, excellent electrical performance, and long term stability 1 – 3 . Recently, researches have focused on enhancing the gas sensing performance of ZnO nanostructures by using nanostructured materials with ultra-high specific surface areas 4 – 6 , appropriate element doping 7 – 10 , surface decoration with noble metals (Au, Pt, Pd, and Ag) 11 – 14 nanocomposite 15 – 17 and construction of heterostructure 18 – 22 . Among them, the hierarchical nano-heterostructures have attracted great attention due to their rich architectures, extraordinary properties, and novel applications 23 , 24 .…”