Effect of Ag doping on structural, optical, and photocatalytic properties of ZnO nanoparticles

Core–shell TiO2@ZnO nanorods (NRs) have been fabricated by a simple two step method: growth of ZnO NRs' array by an aqueous chemical technique and then coating of the NRs with a solution of titanium isopropoxide [Ti(OC3H7)4] followed by a heating step to form the shell. The core–shell nanocomposites are composed of single-crystalline ZnO NRs, coated with a thin TiO2 shell layer obtained by varying the number of coatings (one, three and five times). The ultraviolet (UV) emission intensity of the nanocomposite is largely quenched due to an efficient electron–hole separation reducing the band-to-band recombinations. The UV photoconductivity of the core–shell structure with three times TiO2 coating has been largely enhanced due to photoelectron transfer between the core and the shell. The UV photosensitivity of the nanocomposite becomes four times larger while the photocurrent decay during steady UV illumination has been decreased almost by 7 times compared to the as-grown ZnO NRs indicating high efficiency of these core–shell structures as UV sensors.

Core–shell TiO2@ZnO nanorods for efficient ultraviolet photodetection

Fabrication of ZnO–TiO2 nanohybrids for rapid sunlight driven photodegradation of textile dyes and antibiotic residue molecules

Structural and photoluminescence characterization of SnO2: F thin films deposited by advanced spray pyrolysis technique at low substrate temperature

Optical and photocatalytic properties of composite TiO2/ZnO thin films

Influence of annealing temperature on the photoluminescence property of ZnO thin film covered by TiO2 nanoparticles

A ZnO thin film covered by TiO2 nanoparticles is prepared by electron beam evaporation. The structure and surface morphology of the sample are analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Photoluminescence is used to investigate the fluorescent property of the ample. The results show that the ultraviolet (UV) emission of the ZnO thin film is greatly enhanced after it is covered by TiO2 nanoparticles while the green emission is suppressed. The enhanced UV emission mainly results from the fluorescence resonance energy transfer (FRET) between ZnO thin film and TiO2 nanoparticles. This TiO2-ZnO composite thin film can be used to fabricate high-efficiency UV emitters.

Enhanced ultraviolet emission from ZnO thin film covered by TiO 2 nanoparticles

Currently, it is generally known that lens-free holographic microscopy, which has no imaging lens, can realize a large field-of-view imaging with a low-cost setup. However, in order to obtain colorful images, traditional lens-free holographic microscopy should utilize at least three quasi-chromatic light sources of discrete wavelengths, such as red LED, green LED, and blue LED. Here, we present a virtual colorization by deep learning methods to transfer a gray lens-free microscopy image into a colorful image. Through pairs of images, i.e., grayscale lens-free microscopy images under green LED at 550 nm illumination and colorful bright-field microscopy images, a generative adversarial network (GAN) is trained, and its effectiveness of virtual colorization is proved by applying it to hematoxylin and eosin stained pathological tissue samples imaging. Our computational virtual colorization method might strengthen the monochromatic illumination lens-free microscopy in medical pathology applications and label staining biomedical research.

/pdf/deep-learning-virtual-colorful-lens-free-on-chip-microscopy-4tlm9l2vtb.pdf

Deep learning virtual colorful lens-free on-chip microscopy

High-power fiber-to-fiber coupling is extensively used in fiber laser applications, and its performance is determined by coupling efficiency. We demonstrate a novel method for alignment and monitoring efficiency by detecting backscattering power at the fiber end cap. The relationship between alignment error and backscattering power is determined by simulations and experiments. Through this method, a state-of-the-art kW-level fiber-to-fiber optic switch is developed (transmission efficiency >97%). It performs well for longer than 60 min. To the best of our knowledge, it is the first time to establish the mathematical model based on this method. Our results can provide guidance in high-power fiber-to-fiber coupling.

/pdf/alignment-and-efficiency-monitoring-method-of-high-power-1apl4ah9vp.pdf

Hua Shen

Papers

Influence of annealing temperature on the photoluminescence property of ZnO thin film covered by TiO2 nanoparticles

Enhanced ultraviolet emission from ZnO thin film covered by TiO 2 nanoparticles

Deep learning virtual colorful lens-free on-chip microscopy

Alignment and efficiency-monitoring method of high-power fiber-to-fiber coupling

Regulating effect of SiO2 interlayer on optical properties of ZnO thin films