- 标题
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Al-, Ga-, Mg-, or Li-doped zinc oxide nanoparticles as electron transport layers for quantum dot light-emitting diodes
摘要： Colloidal quantum dots and other semiconductor nanocrystals are essential components of next-generation lighting and display devices. Due to their easily tunable and narrow emission band and near-unity fluorescence quantum yield, they allow cost-efficient fabrication of bright, pure-color and wide-gamut light emitting diodes (LEDs) and displays. A critical improvement in the quantum dot LED (QLED) technology was achieved when zinc oxide nanoparticles (NPs) were first introduced as an electron transport layer (ETL) material, which tremendously enhanced the device brightness and current efficiency due to the high mobility of electrons in ZnO and favorable alignment of its energy bands. During the next decade, the strategy of ZnO NP doping allowed the fabrication of QLEDs with a brightness of about 200 000 cd/m2 and current efficiency over 60 cd/A. On the other hand, the known ZnO doping approaches rely on a very fine tuning of the energy levels of the ZnO NP conduction band minimum; hence, selection of the appropriate dopant that would ensure the best device characteristics is often ambiguous. Here we address this problem via detailed comparison of QLEDs whose ETLs are formed by a set of ZnO NPs doped with Al, Ga, Mg, or Li. Although magnesium-doped ZnO NPs are the most common ETL material used in recently designed QLEDs, our experiments have shown that their aluminum-doped counterparts ensure better device performance in terms of brightness, current efficiency and turn-on voltage. These findings allow us to suggest ZnO NPs doped with Al as the best ETL material to be used in future QLEDs.
关键词： electron transport layer,doping,zinc oxide nanoparticles,light-emitting diodes,quantum dots
更新于2025-09-23 15:21:01
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The effect of Zn3N2 phase decomposition on the properties of highly-doped ZnO: Al, N films
摘要： Study of Al-N simultaneous doping and thermal annealing influence on the properties of ZnO films is very important for achievement as p-type conductivity in the films as for improvement the performance of ZnO-based ultraviolet detectors. Highly-doped ZnO:Al,N films containing the Zn3N2 phase (ZnO:Al,N-Zn3N2) were grown on Si substrates by magnetron sputtering using a layer-by-layer growth technique. Our work presents a comparative study of the structure, optical and electronic properties of highly-doped as-grown and annealed ZnO:Al,N films. It was shown that the thermal annealing of ZnO:Al,N-Zn3N2 film at atmospheric conditions allows to decompose the Zn3N2 phase. The features of this phenomena on the properties of ZnO:Al,N films were investigated and discussed in detail by using X-ray diffraction, energy dispersive X-ray analysis, Raman scattering, photoluminescence, X-ray photoelectron spectroscopy and X-ray emission spectroscopy.
关键词： Radio-frequency magnetron sputtering,Zinc oxide,Nitrogen-aluminum doping,Photoluminescence,X-ray photoelectron spectroscopy,Thin films,X-ray diffraction,Raman scattering
更新于2025-09-23 15:21:01
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Improved Photoelectric Properties of ZnO<sub>1-x</sub>/Graphene Heterostructures
摘要： In this work, the photoelectric properties of ZnO1-x/graphene heterostructures were investigated. Such ZnO1-x/graphene heterostructures were constructed from non-stoichiometric zinc oxide (ZnO1-x) film and graphene by first depositing ZnO1-x layer through radio frequency magnetron sputtering onto silicon wafers with SiO2 layer and then transferring graphene via a wet method. It was revealed that such heterostructures could have improved photoelectric properties. Compared with ZnO1-x films, the absorbance of the ZnO1-x/graphene heterostructures in visible and near-infrared region was enhanced; and due to the high conductivity of graphene, the photocurrent was significantly enhanced both in dark and under irradiation of a 700 nm light. By calculating the absolute current gain, it was revealed that the fabricated ZnO1-x/graphene heterostructures would have a higher current gain. Thus, such ZnO1-x/graphene heterostructures would be promisingly applied in visible light to near-infrared detection devices.
关键词： Thin film,Zinc oxide,Photoelectric properties,Device,Graphene
更新于2025-09-23 15:21:01
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Optical and Electrical Performance of ZnO Films Textured by Chemical Etching
摘要： Zinc oxide (ZnO) films were prepared by radio frequency (RF) magnetron sputtering on the glass substrate as transparent conductive oxide films. For silicon solar cells, a proper surface texture is essential to introduce light scattering and subsequent light trapping to enhance the current generation. In this study, the magnetron-sputtered ZnO films were textured by wet-chemical etching in diluted hydrochloric acid (HCl) for better light scattering. The diffuse transmittance of the surface textured ZnO films was measured to evaluate the light scattering. The influence of hydrochloric acid concentration on the morphology, optical and electrical properties of the surface-textured ZnO film was investigated. The ZnO film etched in 0.05M HCl solution for 30 s exhibited average diffuse transmittance in the visible wavelength range of 9.52 % and good resistivity of 1.10 x 10-3 Ω·cm while the as-deposited ZnO film had average diffuse transmittance of 0.51 % and relatively high resistivity of 5.84 x 10-2 Ω·cm. Experimental results illustrated that the optical and electrical performance of ZnO films can be significantly improved by introducing the surface texture through the wet-chemical etching process.
关键词： surface texture,light scattering,diffuse transmittance,resistivity,zinc oxide
更新于2025-09-23 15:21:01
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Role of a Buried Indium Zinc Oxide Layer in the Performance Enhancement of Triboelectric Nanogenerators
摘要： Generally, triboelectric generators (TENGs) demonstrate a considerably lower output current than output voltage; this has largely limited their performance enhancement. Thus, enormous research efforts have been made to address this problem. In this work, we present a simple method to enhance the triboelectric output current by burying an indium zinc oxide (IZO) layer under the triboelectric polymer friction layer. The IZO layer provides large interface density of states, which function as a charge reservoir. During frictional contact-separation motion of the TENG, electrons can be stored in or pumped out of these states. By optimizing the properties of the IZO layer, the output performance of the TENG is greatly improved, generating an output power density of ~25 mW/cm2. Specifically, an output voltage and current density of ~140 V and ~180 μA/cm2 were obtained, which are 4-fold and 9-fold higher, respectively, than a TENG without an IZO layer. The method introduced here suffers less from friction layer wear-out and can effectively enhance the performance of TENGs.
关键词： Triboelectric generator,Indium Zinc Oxide,Interfacial density of state
更新于2025-09-23 15:21:01
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Shape-dependant photocatalytic and antimicrobial activity of ZnO nanostructures when conjugated to graphene quantum dots
摘要： To reduce the bandgap and e-/h+ pairs recombination, zinc oxide nanoflakes (ZnO-NFs) and zinc oxide nanorods (ZnO-NRs) were covalently linked to graphene oxide quantum dots (GQDs). Photocatalytic and antimicrobial activity of ZnO nanohybrids (ZnO-NFs@GQDs and ZnO-NRs@GQDs) were investigated. The formation of the distinct ZnO nanoflakes and ZnO nanorods shaped nanoparticles were evidenced by SEM. The bandgap decreased from 2.98 to 2.61 eV and 3.00 to 2.79 eV for ZnO-NFs@GQDs and ZnO-NRs@GQDs, respectively. Photoluminescence (PL) data showed a similar trend where a larger decrease was obtained for ZnO-NFs@GQDs. Photolysis ruled out adsorption mechanism for the removal of dye. Optical data and PL measurements supported photocatalytic findings that ZnO-NFs@GQDs performed better (80%) than ZnO-NRs@GQDs (18%). ZnO-NRs@GQDs however, showed greater bacterial inhibition when tested against E. coli, P. aeruginosa, B. cereus and S. aureus. The antimicrobial efficiency followed the order: ZnO-NFs < ZnO-NFs@GQDs < ZnO-NRs < ZnO-NRs@GQDs with greater efficiency being against S. aureus. Liquid photocatalysts zinc nanoparticles can thus be used to remove dyes and inhibit bacterial growth in aqueous solution.
关键词： Zinc oxide nanorods,zinc oxide nanoflakes,antimicrobial activity,photocatalysis,graphene quantum dots
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Analysis of the Value Proposition of High-efficiency, Multijunction Solar Modules for Residential Rooftop Installations
摘要： We report for the ?rst time on the impact of a printed indium tin oxide (ITO) layer inserted between a printed silver conductor and solution processed zinc oxide (ZnO) leading to an optimized semiconductor/contact scheme for full print integration. Introducing the ITO interlayer, the contact resistance is reduced by two orders of magnitude. Nanoparticle thin-?lm transistors (TFTs) in this Ag/ITO contact con?guration show improved saturation mobility of 0.53 cm V s with respect to 0.08 cm V s without ITO interlayer. The contact improvement can be attributed to either an increased charge carrier concentration or a reduction of band offsets at the ZnO/electrode interface.
关键词： indium–tin–oxide,zinc oxide (ZnO),thin-?lm transistors (TFTs),Contact resistance
更新于2025-09-23 15:19:57
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Memristive Behavior Enabled by Amorphousa??Crystalline 2D Oxide Heterostructure
摘要： The emergence of memristive behavior in amorphous–crystalline 2D oxide heterostructures, which are synthesized by atomic layer deposition (ALD) of a few-nanometer amorphous Al2O3 layers onto atomically thin single-crystalline ZnO nanosheets, is demonstrated. The conduction mechanism is identified based on classic oxygen vacancy conductive channels. ZnO nanosheets provide a 2D host for oxygen vacancies, while the amorphous Al2O3 facilitates the generation and stabilization of the oxygen vacancies. The conduction mechanism in the high-resistance state follows Poole–Frenkel emission, and in the low-resistance state is fitted by the Mott–Gurney law. From the slope of the fitting curve, the mobility in the low-resistance state is estimated to be ≈2400 cm2 V?1 s?1, which is the highest value reported in semiconductor oxides. When annealed at high temperature to eliminate oxygen vacancies, Al is doped into the ZnO nanosheet, and the memristive behavior disappears, further confirming the oxygen vacancies as being responsible for the memristive behavior. The 2D heterointerface offers opportunities for new design of high-performance memristor devices.
关键词： zinc oxide,2D heterostructures,memristors,atomic layer deposition,oxygen vacancies
更新于2025-09-23 15:19:57
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Zinc-oxide nanoparticle-based saturable absorber deposited by simple evaporation technique for Q-switched fiber laser
摘要： A Q-switched erbium-doped fiber laser (EDFL) incorporating zinc-oxide (ZnO) nanoparticles-based saturable absorber (SA) is proposed and demonstrated. To form the SA, the ZnO nanoparticles, which are originally in the powder form, are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique. By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL, a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW. As the pump power is increased, the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39 μs to 3.65 μs. Additionally, this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW. These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation, which offers the flexibility and easy integration of the SA into a ring laser cavity.
关键词： saturable absorber,zinc oxide,fiber laser,Q-switched
更新于2025-09-23 15:19:57
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Morphology Effect of 1D ZnO Nanostructures Designed by Hydrothermal and Thermal Annealing for Fast Ultraviolet Photodetector Applications
摘要： Zinc oxide (ZnO) nanorods were grown on a ZnO seed layer using the hydrothermal method and subsequently annealed at temperatures of 400–800 °C. The ZnO nanorods annealed at 400 °C exhibited morphology similar to that of the unannealed ZnO nanorods. However, the tips of the ZnO nanorods gradually became rounded and their density and diameter increased with an increase in the annealing temperature. The intensity of the near-band-edge emission increased gradually with an increase in the annealing temperature from 400 to 600 °C but decreased sharply in the case of the nanorods annealed at 800 °C. With respect to the deep-level emissions, broad yellow, orange, and green emissions were observed. Further, the low-temperature photoluminescence spectrum measured at 12 K of the ZnO nanorods annealed at 600 °C contained a donor-bound exciton emission, as well as emissions related to the donor-acceptor pair transition and the first-order and second-order longitudinal optical phonon replicas of the donor-acceptor pair transition. Finally, with respect to the photoresponse, the dark current and photocurrent of the nanorods decreased and their photosensitivity increased with the increase in the annealing temperature.
关键词： Ultraviolet photodetector,Zinc oxide,Photosensitivity,Photoluminescence,Hydrothermal method
更新于2025-09-23 15:19:57