Cu-doped Zn Research Articles

Colloidal synthesis of emission-tunable Cu-doped Zn–In–Se/ZnSe core/shell nanocrystals for lighting and bioimaging applications

Herein, environmentally benign CuI:Zn–In–Se/ZnSe core/shell luminescent inorganic nanocrystals (NCs) were synthesized via a phosphine-free one-pot, two-step organometallic approach with good colloidal quality.

Photocatalytic, dye degradation, and bactericidal behavior of Cu-doped ZnO nanorods and their molecular docking analysis.

Nanostructures of Cu-doped ZnO (Cu:ZnO) were prepared with the chemical precipitation technique with an aim to enhance the photocatalytic and antibacterial properties of ZnO. Phase constitution, the presence of functional groups, optical properties, elemental composition, surface morphology and microstructure were evaluated using an X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer, energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HR-TEM), respectively. Emission spectra were obtained with a photoluminescence (PL) spectroscope whereas interlayer d-spacing was estimated through HR-TEM. ZnO consisted of a hexagonal wurtzite structure. The crystallinity of the sample was observed to increase with increasing doping concentration. The addition of Cu to ZnO served to transform nanoclusters into nanorods as revealed during SEM analysis. Catalytic activity enhanced due to the formation of nanorods, and UV-Vis absorption spectra showed that methylene blue (MB) degraded more efficiently with ZnO nanoclusters compared to the NaBH4 reagent. In addition, the doped NPs showed enhanced bacterial efficiency for G +ve. Finally, a molecular docking study was undertaken to highlight the importance of the binding interactions of the Cu-doped ZnO nanorods with β-lactamase and beta-ketoacyl-acyl carrier protein synthase III (FabH) as possible enzyme targets. This research indicates that Cu-doped Zn nanorods are a highly efficient photocatalyst and can be aptly employed for wastewater treatment and antibacterial applications.

Structural, optical and antibacterial investigation of La, Cu dual doped ZnO nanoparticles prepared by co-precipitation method

La, Cu dual doped ZnO with Cu = 0%-4% were prepared by co-precipitation route. The XRD pattern optimized the Cu content as 2% which restrict the secondary phase formation. The new phase at 38.7° corresponding to CuO (111) and the another phase at 42.3° related to Zn (101) came from un-reacted Zn2+ ions appeared in Cu = 4% doped sample. Zeta potential measurements confirms the stability of the particles. The blue shift of absorption edge and the energy gap from 3.66 eV to 3.99 eV by Cu doping was discussed by the shape of the particles, the distortion of the host lattice and generation of defect concentrations. The characteristic IR peaks around 470-489 cm-1 was related to the octahedral sites of Zn-O for Cu = 0 and 2% which is shifted to 616 cm-1 corresponding to the tetrahedral site at Cu = 4%. The shift in frequency was originated from the dissimilarity in the volume and bond lengths by the substitution of La and Cu in Zn-O. Based on the antibacterial report, it can be concluded that the Cu-doped Zn-La-O solid solution compose an effectual antimicrobial agent against pathogenic microorganisms. Cu = 4% doped sample possessed highest bacterial killing capacity because of the enhanced crystallite size and high density of oxygen vacancies which led the higher ROS values. Tuning of crystallite size and energy gap and the enhanced bactericial killing capacity by Cu addition is useful for opto-electronic device and medical applications.

Investigating Photoluminescence Mechanism of Cu-doped Zn–In–Se Quantum Dots by Zn/In Ratio

We investigate the composition-dependent photoluminescence (PL) spectra of Cu-doped Zn–In–Se quantum dots (QDs) to determine the mechanism of radiative recombination of the interband transition. As the Zn/In ratio increases, a systematic blue shift in the dominant broad emission occurs from 648 to 552 nm, with a fixed narrow peak at 465 nm. Based on the nearly constant 3.2 nm nanoparticle size, as determined by high-resolution transmission electron microscopy, the quantum size effect of the Zn/In ratio can be excluded. X-ray diffraction and Raman results demonstrate the formation of multiple phases including ZnIn2Se4, ZnSe, and In2Se3 in all samples, as well as Cu2+ ions occupying Zn2+ sites in the QD lattice. The band structure in the Cu-doped Zn–In–Se QDs is determined via UV–vis absorption spectra and cyclic voltammetry curves, and the defect levels in the gap are identified by use of PL and PL excitation spectra. The enhanced 465 nm emission is ascribed to zinc interstitial (Zni) defects in the increa...

Thermal stability of photoluminescence in Cu-doped Zn-In-S quantum dots for light-emitting diodes.

The photoluminescence (PL) properties of the Cu:Zn-In-S core quantum dots (QDs) and core-shell QDs were systematically investigated by using steady-state and time-resolved PL spectra at temperatures ranging from 80 to 400 K. The effects of the shell structure and the host bandgap on the thermal stability of Cu dopant emissions were studied by measuring the change in the PL intensity and the lifetime. It was found that the PL intensities and lifetimes of the core and core/shell QDs with green, yellow, and red emissions almost decrease with increasing temperatures while their PL was quenched at 300 K and 400 K, respectively, indicating the shell-enhanced thermal stability of the PL. The emission wavelength of the QDs as a function of temperature was also provided. The mechanisms of Cu dopant emission and thermal quenching were discussed. Finally, the green, yellow, red, and white light emitting light emitting diodes (LEDs) were fabricated based on Cu:Zn-In-S QDs.

Color-tunable photoluminescence of Cu-doped Zn–In–Se quantum dots and their electroluminescence properties

Cu-doped Zn–In–Se QDs with color-tunable photoluminescence emissions are synthesized, and the as-fabricated QD-LEDs exhibit a luminous efficiency of 0.97 cd A−1.

Single-step direct fabrication of luminescent Cu-doped Zn(x)Cd(1-x)S quantum dot thin films via a molecular precursor solution approach and their application in luminescent, transparent, and conductive thin films.

Luminescent Cu-doped ZnxCd1-xS quantum dot thin films have been directly fabricated via a facile solution method in open air. Cu2O, ZnO, and Cd(OH)2 were used as starting materials, and 3-mercaptopropionic acid was used as the capping agent. The effects of Cu dopant concentration, sintering temperature, and sintering time on the photoluminescence properties of Cu-doped ZnxCd1-xS nanocrystal thin films have been systematically investigated. As-prepared quantum dot thin films exhibit tunable emission covering the whole visible light region and the absolute photoluminescence quantum yields can reach as high as 25.5%, which have high potential for applications in luminescent, transparent, and conductive thin films.

Color-Tunable Highly Bright Photoluminescence of Cadmium-Free Cu-Doped Zn–In–S Nanocrystals and Electroluminescence

A series of Cu doped Zn–In–S quantum dots (Cu:Zn–In–S d-dots) were synthesized via a one-pot noninjection synthetic approach by heating up a mixture of corresponding metal acetate salts and sulfur powder together with dodecanethiol in oleylamine media. After overcoating the ZnS shell around the Cu:Zn–In–S d-dot cores directly in the crude reaction solution, the resulting Cu:Zn–In–S/ZnS d-dots show composition-tunable photoluminescence (PL) emission over the entire visible spectral window and extending to the near-infrared spectral window (from 450 to 810 nm), with the highest PL quantum yield (QY) up to 85%. Importantly, the initial high PL QY of the obtained Cu:Zn–In–S/ZnS d-dots in organic media can be preserved when transferred into aqueous media via ligand exchange. Furthermore, electroluminescent devices with good performance (with a maximum luminance of 220 cd m–2, low turn-on voltages of 3.6 V) have been fabricated with the use of these Cd-free low toxicity yellow-emission Cu:Zn–In–S/ZnS d-dots as an active layer in these QD-based light-emitting diodes.

Cu-Doped ZnO Hemispherical Shell Structures: Synthesis and Room-Temperature Ferromagnetism Properties

We report a simple chemical vapor deposition method to fabricate Cu-doped ZnO hemispherical shell structures with room-temperature ferromagnetism (RTFM). Through a series of controlled experiments by changing the growth temperature and reaction time, we observe the evolution of product morphology from whole spherical structures into partially broken shells and hemispherical shells at different temperatures together with the reinforced hemispherical shells with the reaction time extended. The growth mechanism of the ZnO:Cu hemispherical shell structures has been proposed to involve the synthesis of Cu-doped Zn sphere, surface oxidation, and sublimation of the inner Zn from the broken shell. The structural and optical properties of the ZnO:Cu system with different Cu contents (below 4%) were investigated by X-ray diffraction, Raman spectroscopy, and photoluminescence measurements indicating that the Cu ions were successfully substituted into the Zn2+ lattice sites, and more intrinsic structural defects were...

Properties of Cu-doped Zn Te thin films prepared by closed space sublimation (CSS) techniques

Properties of Cu-doped Zn Te thin films prepared by closed space sublimation (CSS) techniques