Hierarchical ZnO Nanosheet-Nanorod Architectures for Fabrication of Poly(3-hexylthiophene)/ZnO Hybrid NO₂ Sensor

Abstract

A facile one-step solution method has been developed here to fabricate hierarchical ZnO nanosheet-nanorod architectures for compositing with poly(3-hexylthiophene) (P3HT) for fabricating a hybrid NO2 sensor. The hierarchical ZnO nanosheet-nanorod architectures were controllably synthesized by aging the solutions containing 0.05 mol·L(-1) Zn(2+) and 0.33 mol·L(-1) OH(-) at 60 °C through a metastable phase-directed mechanism. The concentration of OH(-) played a huge role on the morphology evolution. When the [OH(-)] concentration was decreased from 0.5 to 0.3 mol·L(-1), the morphology of the ZnO nanostructures changed gradually from monodispersed nanorods (NR) to nanorod assemblies (NRA), and then to nanosheet-nanorod architectures (NS-NR) and nanosheet assemblies (NSA), depending on the formation of various metastable, intermediate phases. The formation of NS-NR included the initial formation of ZnO nanosheets/γ-Zn(OH)2 mixed intermediates, followed by the dissolution of Zn(OH)2, which served as soluble zinc source. Soluble Zn(OH)2 facilitated the dislocation-driven secondary growth of ZnO nanorod arrays on the primary defect-rich nanosheet substrates. Hybrid sensors based on composite films composed of P3HT and the as-prepared ZnO nanostructures were fabricated for the detection of NO2 at room temperature. The P3HT/ZnO NS-NR bilayer film exhibited not only the highest sensitivity but also good reproducibility and selectivity to NO2 at room temperature. The enhanced sensing performance was attributed to the formation of the P3HT/ZnO heterojunction in addition to the enhanced adsorption of NO2 by NS-NR ZnO rich in oxygen-vacancy defects.

Two-Dimensional Zinc Oxide Nanostructures for Gas Sensor Applications

“…Wang et al [74] synthesized hierarchical nanosheet-nanorods architectures (NS-NR) for compositing with poly(3-hexylthiophene) (P3HT) by a one-step solution method. A silicon wafer was used as the sensor substrate where Ti-Au interdigitated electrodes were deposited by RF sputtering.…”

Control of oxygen vacancies in ZnO nanorods by annealing and their influence on ZnO/PEDOT:PSS diode behaviour

“…Due to its n-type semiconducting behaviour, radiation hardness, photoconductivity, piezoelectric properties and chemical stability, ZnO is considered as a promising material to be assembled in functional structures such as p-n junctions. [1][2][3][4][5][6][7][8] It has been applied in piezoelectric energy harvesting systems, 9,10 photodetectors, 4 light-emitting diodes 11 and photovoltaics. [12][13][14] Nanostructured…”

A Review on the Fabrication of Hierarchical ZnO Nanostructures for Photocatalysis Application

“…The above developed approaches allowed the stepwise control of experimental conditions and provided an opportunity for the rational design and synthesis of controlled architectures in nanostructures. Recently, we reported hierarchical ZnO architectures assembled by nanosheets and nanorods via a facile solution method [41]. In this reaction system, the critical morphology controller is the concentration of OH − .…”

“…Recently, we reported hierarchical ZnO architectures assembled by nanosheets and nanorods via a facile solution method [41]. In this reaction system, the critical morphology controller is the concentration of OH − .…”