- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Beta-lead oxide quantum dot (β-PbO QD)/polystyrene (PS) composite films and their applications in ultrafast photonics
摘要： Polymer composite films, particularly those based on polymers and layered nanomaterials, are attractive materials for exploiting the properties of multiple materials for applications in electronics and photonics. In this work, a beta-lead oxide quantum dot (β-PbO QD)/polystyrene (PS) composite film is successfully fabricated by a solution blending method. The β-PbO QDs are well-distributed within a β-PbO QD/PS composite film and the composite film is transparent and flexible. Owing to the almost complete insolubility of both β-PbO QDs and PS, the as-fabricated β-PbO QD/PS composite film holds the nonlinear photonic response from 540 nm to 1060 nm under complete water immersion, confirming its excellent stability to high humidity. Additionally, the β-PbO QD/PS composite film exhibits a considerable capacity for optical modulation owing to a strong nonlinear absorption coefficient compared with those of other two-dimensional (2D) materials. On the basis of a home-made β-PbO QD/PS composite film saturable absorber, stable mode-locked pulses at 1060 nm are generated under humid conditions. It is anticipated that the β-PbO QD/PS composite films enable the exploitation of new waterproof, flexible photonic devices based on functional 2D materials and polymers.
关键词： composite films,mode-locked pulses,ultrafast photonics,polystyrene,nonlinear absorption,beta-lead oxide quantum dot
更新于2025-11-19 16:56:42
-
The Effects of the Content of NiO on the Microstructure and Photocatalytic Activity of the NiO/TiO2 Composite Film
摘要： The NiO/TiO2 composite films with the NiO content of 3 %, 5 %, 10 %, 13 %, 15 % and 20 % were prepared by mechanical coating technology and subsequent oxidation process. The composition and microstructure of the films were analyzed by X-ray Diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic activity was evaluated and the effects of the content of NiO on microstructure and photocatalytic activity of the films were studied. The results show that NiO particles are dispersed in the Ti coatings, and the NiO concentration in the inner layer of the coatings is higher than in the outer layer. With the addition of NiO in the NiO/Ti coating, the ductility is deteriorated and the thickness is reduced of the NiO/Ti coatings. The films with NiO/TiO2/Ti composite microstructure are obtained by the oxidation of NiO/Ti coatings. Photocatalytic efficiency of the films is obviously enhanced with the help of the p-n junction heterostructure in the NiO/TiO2 films. The optimum content of NiO is about 13 %, and the degradation rate of methyl orange solution reaches the maximum value of 88.44 %.
关键词： mechanical coating technology,NiO content,photocatalytic activity,NiO/TiO2 composite films
更新于2025-09-23 15:22:29
-
Electrical and optical responses of composite films based on N,N-dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene
摘要： N,N-dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene ex-situ and in-situ composite films with 2% concentration of graphene were first prepared and systematically investigated. The crystallinity of DSTMS-based composite films were confirmed by XRD analysis, and the functional groups of composite films can be obtained by FT-IR. Optical absorptions were recorded using UV–Vis-NIR spectral analysis, and the band gap and extinction coefficient of the films were calculated. The thermal stability of the composite films were analyzed by TG/DSC. The pressure sensitive resistance test showed that the pressure sensitive signal of the composite films were significantly increased after graphene added, while the signal of DSTMS film eventually disappears. This work expands the application of organic nonlinear crystal DSTMS in optics and electricity by doping graphene.
关键词： DSTMS,electrical properties,graphene,composite films,optical properties
更新于2025-09-23 15:21:21
-
One-step synthesis and deposition of ZnFe2O4 related composite films via SPPS route for photodegradation application
摘要： Binary spinel-type metal oxides (AB2O4) related materials, including ferrites (AFe2O4), are attractive photocatalysts thanks to their excellent visible light response for the photodegradation of organic pollutants. Currently, these materials are synthesized via conventional chemical routes suffering from long preparation duration and multistep. Solution Precursor Plasma Spray (SPPS) process is a single-step method for depositing photocatalytically active zinc ferrite-based films within several minutes. The influence of the precursor ratio on the microstructures and phase compositions of the ZnFe2O4 films was investigated by XRD and Raman analyses. In addition, two optimized ZnFe2O4 films were prepared by increasing the ZnO loading and tailoring injection pattern of the precursor solution. The surface morphologies and optical bandgap were also determined by SEM and UV-visible spectroscopy. The photocatalytic activities of the ZnFe2O4 films were evaluated through the degradation of the Orange II dye and of tetracycline hydrochloride under UV or visible light irradiation. The results show that compositional ratios and composition distribution of the ZnFe2O4 films prepared via SPPS played a key role on the photocatalytic activity. The SPPS route was demonstrated to be a promising method for the synthesis and the deposition of metal oxide (i.e. perovskite type and spinel type) films within a single-step for functional applications.
关键词： Solution Precursor Plasma Spray,Photocatalytic degradation,zinc ferrite,composite films
更新于2025-09-23 15:21:01
-
Preparation of graphene films bridged with Ag nanowires and its application in heterojunction solar cells
摘要： In this work, efforts were made to further improve the performance of heterojunction solar cells based on graphene films. A dip-drawing method was developed to synthesize the Ag nanowires/graphene composite film (Ag NWs/G). Then, Ag nanowires were superimposed on the single layer graphene and was used as an upper electrode of the solar cell. As expected, this combination has taken advantage of the high carrier concentration of Ag nanowires and high carrier mobility of graphene. Ag NWs/G composite films with high conductivity and transmittance were obtained. The Raman spectral characterization verified the typical feature of graphene films. And, the effect of Ag nanowires on graphene film was demonstrated. Ag nanowires can effectively reduce the resistivity of graphene films, thus solve the problem of carrier recombination. Efficiency of 8.74% was achieved for Ag NWs/G film based solar cells without any antireflective coatings. The modification roles of the Ag NWs/G film in solar cell were discussed. It was verified that the superposition of Ag nanowires can highly facilitate the transmission of current. As a whole, the Ag NWs/G composite film with high transmittance and low square resistance will be more suitable as a transparent electrode, as well as a function layer.
关键词： Dip-drawing method,Ag NWs/G composite films,Multiple functions,Heterojunction solar cells
更新于2025-09-19 17:13:59
-
Optical linearity and bandgap analysis of RhB-doped PMMA/FTO polymeric composites films: A new designed optical system for laser power attenuation
摘要： Thin films of PMMA doped with Rhodamine B-dye have deposited successfully on a fluorine-doped tin oxide (FTO) glass substrate as a new optical system by using a spin coating method. This new system is promising to be used in various technological applications as solar energy cells, electronic apparatuses, devices of optical filter properties and optoelectronic tools. X-ray diffraction (XRD) illustrates a uniform and semicrystalline structure in nature for the obtained thin films. A spectrophotometric investigation was applied on the prepared thin films at the range of (300–2500 nm) for the wavelength. Both linear refractive index and absorption index values were measured to be reduced as the wavelength was raised. Tauc’s plot indicated that direct and indirect transitions were displayed by the thin film. Both direct and indirect bandgaps were calculated and analyzed. Continuous waves of the green laser beam (operating at 532), and He-Ne laser beam (operating at 632.8 nm) were used to study the optical properties of the prepared thin films with different dye concentrations. The results illustrated that the polymeric composites films are highly attenuated for the laser beam of 532 nm. The designed RhB-doped PMMA/FTO composites can be extensively appropriate to the optoelectronic applications.
关键词： Laser power attenuations,Polymeric composite films,Direct and indirect bandgap,Rhodamine B dye,PMMA/FTO films
更新于2025-09-11 14:15:04
-
Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification || Concurrent Multi-Target Laser Ablation for Making Nano-Composite Films
摘要： New method of using laser ablation for film deposition that can be called as concurrent multi-beam multi-target matrix-assisted pulsed laser evaporation and pulsed laser deposition (MBMT-MAPLE/PLD) is described. Practical MBMT-MAPLE/PLD system built at Dillard University has three separate laser beams, three targets and the remotely controlled plume overlapping mechanism that provides even mixing of the target materials during their deposition on the substrate. The system accommodates MAPLE targets in the form of polymer solutions frozen with flowing liquid nitrogen. The feasibility of the method was demonstrated when it was used for making polymer nano-composite films with two inorganic additives: upconversion fluorescent phosphor NaYF4:Yb3+, Er3+ and aluminum-doped ZnO (AZO). Three laser beams, an infrared 1064-nm beam for the MAPLE and two 532-nm beams for the PLD targets, were concurrently used in the process. The fabricated nano-composite films were characterized using X-ray diffraction, scanning electron microscopy (SEM), optical fluorescent spectroscopy, and the measurement of the quantum efficiency (QE) of the upconversion fluorescence. The size of the inorganic nanoparticles varied in the range 10–200 nm. The AZO additive increased QE by 1.6 times. The conclusion was made on the feasibility of MBMT-MAPLE/PLD method for making multi-component nano-composite films for various applications.
关键词： matrix-assisted pulsed laser evaporation,polymer nano-composite films,pulsed laser deposition,laser ablation
更新于2025-09-11 14:15:04
-
Improving the efficiency of silicon solar cells using in situ fabricated perovskite quantum dots as luminescence downshifting materials
摘要： Luminescence downshifting (LDS) layer integration has been proven to be an efficient way to ameliorate the poor UV-blue spectral response and improve the power conversion efficiency (PCE) for solar cells (SCs). By employing an in situ fabricated CH3NH3PbBr3 (CH3NH3?=?methylammonium, MAPbBr3) quantum dot/polyacrylonitrile (PAN) composite film as the LDS layer, we observed a clear enhancement in the external quantum efficiency (EQE) for silicon SCs, predominantly in the UV-blue region. With a theoretically calculated intrinsic LDS efficiency (ηLDS) of up to 72%, silicon SCs with the LDS layer exhibited an absolute value of 1% for PCE improvement in comparison to those without the LDS layer. The combination of easy fabrication and low cost makes it a practical way to achieve photovoltaic enhancement of Si-based SCs.
关键词： luminescence downshifting,quantum dots,composite films,silicon solar cells,perovskite
更新于2025-09-11 14:15:04