First-principles insights on the electronic and optical properties of ZnO@CNT core@shell nanostructure

Abstract

In recent years, various kinds of ZnO-based core@shell nanomaterials have been paid much attention due to their widespread applications in the fields of physics, chemistry and energy conversion. In this work, the electronic and optical properties of a new type of ZnO-based one-dimensional core@shell nanostructure, which is composed of inner ZnO nanowire and outer carbon nanotube (CNT), is calculated based on the first-principles density functional theory (DFT). Calculation results suggest that the ZnO nanowire encapsulated in (9, 9)-CNT is the most stable structure from the view of formation energy. The interaction between the inner ZnO nanowire and the outer (9, 9) CNT belongs to a weak van der Waals type. The complex structure is found to possess metallicity for the outer (9, 9) CNT and maintain the wide band gap nature for the inner ZnO nanowire. Under the different external strains, the charge redistribution between inner ZnO nanowire and outer CNT caused by electron tunneling leads to the shift of Dirac point and the band narrowing of inner ZnO nanowire. The inner ZnO nanowire only has light absorption in the UV region, which is consistent with its optical property originating from its wide bandgap nature.

Experimental and density functional study of the light-assisted gas-sensing performance of a TiO2–CoFe2O4 heterojunction

“…59,60 Although DFT methods lacked complete accuracy for calculating data, they were good at predicting basic trends and physical mechanisms of the calculation systems. 61…”

“…59,60 Although DFT methods lacked complete accuracy for calculating data, they were good at predicting basic trends and physical mechanisms of the calculation systems. 61 Moreover, Fig. 7a and b reveals that TiO 2 was an indirect bandgap material and CoFe 2 O 4 was a direct bandgap material.…”

Ab Initio Calculations of Chitosan Effects on the Electronic Properties of Unpassivated Triangular ZnO Nanowires Oriented along [0001] Directions

“… 1 Moreover, ZnO is a promising nanomaterial for a wide range of technological applications, including photodetectors, solar cells, photonic crystals, and transparent conducting oxides. 2 Therefore, ZnO nanowires (ZnONWs) have been one of the most studied nanomaterials in the last two decades. Due to their unique properties and applications, these NWs can be used in LEDs, nanolasers, gas detectors, sensors, photocatalysis, and solar cells.…”

“…Zinc oxide (ZnO) is a II–VI semiconductor with a wide band gap (3.37 eV), a high exciton binding energy (60 meV), and excellent thermal stability . Moreover, ZnO is a promising nanomaterial for a wide range of technological applications, including photodetectors, solar cells, photonic crystals, and transparent conducting oxides . Therefore, ZnO nanowires (ZnONWs) have been one of the most studied nanomaterials in the last two decades.…”

Solar-Light-Driven Efficient ZnO–Single-Walled Carbon Nanotube Photocatalyst for the Degradation of a Persistent Water Pollutant Organic Dye

“…Zinc oxide (ZnO) is a semiconductor with an exciton binding energy (60 meV), large bandgap (3.37 eV), and outstanding stability against thermal decomposition. Nanosized ZnO materials have been demonstrated to be very useful in a large number of technical applications, including photocatalysts, photonic crystals, photodetectors, transparent conducting oxides, biosensors, photoelectrochemical water-splitting devices, solar cells, bone tissue engineering scaffolds, and supercapacitors [7][8][9][10]. Nanosized and/or nanostructured ZnO is a suitable photocatalyst because of its nontoxicity, low cost, wide bandgap, availability of a sizeable active portion (or area) for photocatalytic reaction, large aspect ratio, and high photosensitivity [1][2][3].…”