Functionalization of Pristine, Metallic, and Semiconducting-SWCNTs by ZnO for Efficient Charge Carrier Transfer: Analysis through Critical Coagulation Concentration

Abstract

Noncovalent functionalization of single-walled carbon nanotubes (SWCNT) by semiconducting oxides is a majorly sought technique to retain individual properties while creating a synergetic effect for an efficient heterostructure charge transfer. Three types of electronically and optically different SWCNTs: metallic (m), semiconducting (s), and pristine (p) are functionalized by ZnO using a facile sonication method. The physicochemical and morphological properties of the ZnO-functionalized SWCNTs, m-SWCNT+ZnO, s-SWCNT+ZnO, and p-SWCNT+ZnO, are analyzed by advanced characterization techniques. Evidence of charge transfer between SWCNT and ZnO is observed with an increase in charge carrier lifetime from 3.31 ns (ZnO) to 4.76 ns (s-SWCNT+ZnO). To investigate the optimum interaction between SWCNTs and ZnO, critical coagulation concentrations (CCC) are determined using UV–vis absorption spectroscopy for m-SWCNT, s-SWCNT, and p-SWCNT using different molar concentrations of ZnO as the coagulant. The interaction and coagulation mechanisms are described by the modified DLVO theory. Due to the variation in dielectric values and electronic properties of SWCNTs, the CCC values obtained have differed: m-SWCNT (1.9 × 10 –4 ), s-SWCNT (3.4 × 10 –4 ), and p-SWCNT (2 × 10 –4 ). An additional analysis of the aggregates and supernatants of the CCC experiments is also shown to give an insight into the interaction and coagulation processes, explaining the absence of influence exerted by sedimentation and centrifugation.

Polarization detection of ultraviolet light using ZnO microwires

“…Notably, the polarization-sensitive properties of one-dimensional (1D) ZnO structures, due to their anisotropic morphology, have been demonstrated, and their high crystallinity results in efficient electronic transmission. 17 However, polarization-sensitive UV detection based on 1D ZnO has not been fully explored. Only a few studies have been conducted, 18,19 and most of these focus on nanoscale GaN and ZnO materials; however, their small size requires complex operations and alignments to improve the polarization characteristics of devices.…”

“…Notably, the polarization-sensitive properties of one-dimensional (1D) ZnO structures, due to their anisotropic morphology, have been demonstrated, and their high crystallinity results in efficient electronic transmission 17 . However, polarization-sensitive UV detection based on 1D ZnO has not been fully explored.…”

Highly Sensitive Electrochemical Detection of ERα Based on AuNPs-SWCNT Composites and Hemin@HKUST-1

“…[15][16][17] Single-walled carbon nanotube (SWCNT) is a kind of carbon nanomaterial with excellent artificial, which are widely used in electrical, optical, chemical and other fields due to its unique planar structure and excellent electronic properties. 18 SWCNT can be functionalized by non-covalent or covalent methods, and the materials in the non-covalently functionalized composites exhibit synergistic effect that improves overall performance. 19 Gold nanoparticles (AuNPs) are the most widely used metal nanoparticles owing to the advantages of large specific surface area and superior electrical conductivity.…”