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It is time for industry to pay a serious heed to the application and quality-dependent research on the most important solution growth methods for ZnO, namely, aqueous chemical growth (ACG) and microwave-assisted growth (MAG) methods. This study proffers a critical analysis on how the defect density and formation behavior of ZnO nanostructures (ZNSs) are growth method-dependent. Both antithetical and facile methods are exploited to control the ZnO defect density and the growth mechanism. In this context, the growth of ZnO nanorods (ZNRs), nanoflowers, and nanotubes (ZNTs) are considered. The aforementioned growth methods directly stimulate the nanostructure crystal growth and, depending upon the defect density, ZNSs show different trends in structural, optical, etching, and conductive properties. The defect density of MAG ZNRs is the least because of an ample amount of thermal energy catered by high-power microwaves to the atoms to grow on appropriate crystallographic planes, which is not the case in faulty convective ACG ZNSs. Defect-centric etching of ZNRs into ZNTs is also probed and methodological constraints are proposed. ZNS optical properties are different in the visible region, which are quite peculiar, but outstanding for ZNRs. Hall effect measurements illustrate incongruent conductive trends in both samples.

Novel chitosan–zinc copper oxide (Zn1−xCuxO) composites were electrochemically synthesized through galvanostatic deposition. The prepared chitosan-based composite thin films were elaborately investigated to determine their structural, morphological, compositional, impedance, and corrosion properties. X-ray diffraction analysis was performed to reveal their structural orientation of composite thin films. Energy dispersive analysis by X-ray evidently confirmed the existence of Zn, Cu, and O in the composite thin films. Nyquist plots revealed that the chitosan-Zn1−xCuxO thin films had obvious semi-circular boundaries, and higher resistance was observed for chitosan-ZnO due to the grain boundary effect. Corrosion properties were evaluated using both an electrochemical method and the ASTM weight gain method, which revealed good corrosion rates of 34 and 35 × 10−3 mm/y, respectively, for chitosan-ZnO thin film.

We present the transient current response for a ZnO nanorod‐based doubly transparent UV sensor. ZnO nanorods (ZNRs) are sandwiched between indium tin oxide (ITO) electrodes to make the device doubly transparent on a flexible polyethylene terephthalate (PET) substrate. The average ZNR length and diameter are 1.7 μm and 62 nm, respectively, and the ITO is perfectly sputtered upon ZNR surface. All the ZNRs are c‐axis oriented perpendicular to the substrate with a typical hexagonal wurtzite ZnO structure. Photoluminescence spectra show a typical high‐intensity peak near 375 nm and a broad peak in the visible region. UV sensing is confirmed by testing ZNR current–voltage characteristics and transient current response under UV on–off conditions for straight and inflexed ZNRs. The sensor shows a 2.3 times increase in current intensity under UV illumination at 4 V. The transient current shows a typical sinusoidal wave‐like response with three prominent regions under constant voltage supply. The recovery time is almost five‐times of the response time, which confirms the five‐times faster boundary hole trapping in the sensor than their release on the flexible substrate. Also, the current intensity decreases for an unilluminated flexed device and increases for an UV‐illuminated flexed device because of strain‐induced ZNR piezotronic effects under flexible deformation.