Size Dependence of First-order Hyperpolarizability of CdS Nanoparticles Studied by Hyper-Rayleigh Scattering

The second-order optical nonlinearity of CdS nanoparticles with different diameters of 28.0, 30.0, 31.5, 50.0, and 91.0 A was studied by hyper-Rayleigh scattering technique. Results show that the first-order hyperpolarizability P value per CdS partiele decreases as size is reduced to diameter of 31.5 A; however, as CdS size further decreases, this trend is reversed and (J value increases. Substantially, the normalized P value per CdS formula unit, β0, exhibits systematic enhancement with decreasing size. This phenomenon is interpreted in terms of a so-called surfaee contribution mechanism.

Second-order Nonlinearities of CdS Nanoparticles Studied by Hyper-Rayleigh Scattering Technique

A series of CdS nanoparticles with different surfaces were prepared by colloidal chemical method and reverse micelle method. Their second-order nonlinear optical (NLO) properties were experimentally studied in solution by newly developed hyper-Rayleigh scattering (HRS) technique. The results show that 'per particle' first-order hyperpolarizability beta values are sensitive To the synthetic method and the surface chemical modification.

Hyperfine splitting and ferromagnetism in CdS:Mn nanoparticles for optoelectronic device applications

Manganese(Mn)doped cadmium sulphide(Cd S)nanoparticles were synthesized using a chemical method.It was possible to decrease Cd S:Mn particle size by increasing Mn concentration.Investigation techniques such as ultraviolet-visible(UV-Vis)absorption spectroscopy and photoluminescence(PL)spectroscopy were used to determine optical properties of Cd S:Mn nanoparticles.Size quantization effect was observed in UV-Vis absorption spectra.Quantum efficiency for luminescence or the internal magnetic field strength was increased by doping Cd S nanoparticles with Mn element.Orange emission was observed at wavelength~630 nm due to ^(4)T_1→^(6)A_1 transition.Isolated Mn~(2+)ions arranged in tetrahedral coordination are mainly responsible for luminescence.Luminescence quenching and the effect of Mn doping on hyperfine interactions in the case of Cd S nanoparticles were also discussed.The corresponding weight percentage of Mn element actually incorporated in doping process was determined by atomic absorption spectroscopy(AAS).Crystallinity was checked and the average size of nanoparticles was estimated using the X-ray diffraction(XRD)technique.Cd S:Mn nanoparticles show ferromagnetism at room temperature.Transmission electron microscopy(TEM)images show spherical clusters of various sizes and selected area electron diffraction(SAED)patterns show the polycrystalline nature of the clusters.The electronic states of diluted magnetic semiconductors(DMS)ofⅡ-Ⅵgroup Cd S nanoparticles give them great potential for applications due to quantum confinement.In this study,experimental results and discussions on these aspects have been given.

Covalent organic framework stabilized CdS nanoparticles as efficient visible-light-driven photocatalysts for selective oxidation of aromatic alcohols

Noble-metal-free photocatalysts with high and stable performance provide an environmentally-friendly and cost-efficient route for green organic synthesis.In this work,CdS nanoparticles with small particle size and different amount were successfully deposited on the surface of covalent organic frameworks(COFs).The deposition of suitable content of CdS on COFs could not only modify the light adsorption ability and the intrinsic electronic properties,but also enhance the photocatalytic activity and cycling performance of CdS for the selective oxidation of aromatic alcohols under visible light.Especially,COF/CdS-3 exhibited the highest yield(97.1%)of benzalde hyde which is approximately 2.5 and 15.9 times as that of parental CdS and COF,respectively.The results show that the combination of CdS and COF can improve the utilization of visible light and the separation of photo-generated charge carriers,and COF with theπ-conjugated system as supports for CdS nanoparticles could provide efficient electron transport channels and improve the photocatalytic performance.Therefore,this kind of COF-supported photocatalysts with accelerated photo-induced electrons and charge-carrier separation between semiconductors possesses great potentials in future green organic synthesis.

Photoelectrochemical glucose biosensor incorporating CdS nanoparticles

A novel photoelectrochemical biosensor incorporating nanosized CdS semiconductor crystals with enzyme to enhance photochemical reaction has been investigated. CdS nanoparticles were synthesized by using dendrimer PAMAM as inner templates. The CdS nanoparticles and glucose oxidase （GOD） were immobilized on Pt electrode via layer-by-layer （LbL） technique to fabricate a biological-inorganic hybrid system. Under ultraviolet light, the photo-effect of the CdS nanoparticles showed enhancement of the biosensor to detect glucose. Pt nanoparticles were mixed into the Nation film to immobilize the CdS/enzyme composites and to improve the charge transfer of the hybrid. Experimental results demonstrate the desirable characteristics of this biosensing system, e,g. a sensitivity of 1.83 μA/（mM cm^2）, lower detection limit （1 μM）, and acceptable reproducibility and stability,

Photorefractivity in a Bi-functional Polymer Nanocomposites Sensitized by CdS Nanoparticle

We report an organic/inorganic hybridized nanocomposite consisting of a bi-functional poly（N-vinyl）-3-[p-nitrophenylazo]carbazolyl serves as a polymeric charge-transporting and second-order nonliner optical matrix, and CdS nanoparticles as photosensitizers to manifest photorefractive （PR） effect. The unpoled PVNPAK film exhibits a second harmonic generation （SHG） coefficient of 4.7 pm/V due to the possibility of self-alignment of the azo chromophore. Significant enhancement of photoconductivity is noticed with the increase of CdS nanoparticles concentration. The photorefractive property of the polymer nanocomposites were determined by two-beam coupling （TBC） experiment. The TBC gain and diffraction efficiency of 11.89 cm-1 and 3.2% were obtained for PVNPAK/CdS at zero electrical field.

Uniform Rice-like CdS Particles Prepared from Water-in-oil Microemulsions

Uniform rice-like CdS particles were synthesized in cyclohexane/Triton X-100/n-pentanol/water quaternary microemulsions. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, and electron diffraction. The results indicate that the size and the shape of the rice-like CdS particles can be influenced by the molar ratio of water to the surfactant（w value） and the reactant concentrations.

Interfacing biosynthetic CdS with engineered Rhodopseudomonas palustris for efficient visible light-driven CO_(2)-CH_(4) conversion

Engineered photosynthetic bacterium Rhodo-pseudomonas palustris is excellent at one-step CO_(2) biomethanation and can use near-infrared light sources,overcoming the limitations of conventional photosynthetic systems.The current study constructed a biohybrid system that deposited CdS nanoparticles on R.palustris.This biohybrid system broadens the capture of sustainable solar energy,achieving a 155 nmol-mL-biological CH,production under full visible light irradiation,13.4-fold of that by the pure R.palustris.The transcriptome profiles revealed that gene expression related to photosynthetic electron transfer chain,nitrogenase,nanofilaments,and redox stress defense was activated.Accordingly,we attributed the much-enhanced CO_(2) biomethanation in the biohybrid system to the remarkable increase in the intracellular reducing power and the stronger rigidity of the cells assisted by photoexcited electrons from CdS nanoparticles.Our discovery offers insight and a promising strategy forimproving the current CO_(2)-CH_(4) biomanufacturing system.

Magnetic particles and cadmium sulfide nanoparticles tagging for signal-amplifying detection of nucleic acids

A versatile DNA recognition system using cadmium sulfide nanoparticles (CdS NPs) as labels was proposed for ultrasensitive detection of specific sequence DNA based on target recycling. This strategy utilized the magnetic particles (MNPs) for the immobilization of linker DNA and CdS NPs and the subsequent target DNA hybridization. Using the unique characteristic of nicking endonuclease for cutting one specific strand of double strand DNA (ds DNA), the linker DNA could be transected and the target DNA could be liberated for re-hybridization and hence the amount of released CdS NPs was enhanced. Due to the advantage of the MNPs and signal amplification from the target recycling, the analyte DNA could be detected by the square-wave stripping voltammetry (SWV) in a wide linear range from 0.4 fM to 100 fM with the detection limit down to 0.08 fM. The proposed DNA detection strategy possesses high sensitivity, satisfactory reproducibility and excellent stability, which might have potential in other DNA biological assays.

Developing hierarchical CdS/NiO hollow heterogeneous architectures for boosting photocatalytic hydrogen generation

The hierarchical binary CdS/NiO hollow heterogeneous architectures(HHAs)with p–n heterojunction are constructed by a facile microwave-assisted wet chemical process for high-efficient photocatalytic hydrogen evolution reaction(HER)from water.The as-designed CdS/NiO HHAs are composed of hexagonal n-type CdS nanoparticles with a size in the range of 20–40 nm attaching to cubic p-type NiO hollow microspheres(HMSs)which are aggregates of porous nanoplates with a thickness of about 20 nm.The photocatalytic water splitting over CdS/NiO HHAs is significantly increased under simulated solar irradiation,among which the most active sample of CdS/NiO-3(the mass ratio of CdS to NiO is 1:3)exhibits the fastest photocatalytic HER rate of 1.77 mmol∙g^(−1)∙h^(−1),being 16.2 times than that of pure CdS.The boosted photocatalytic HER could be attributed to the synergistic effect on the proportional p–n heterojunction with special hierarchical hollow and porous morphology,an enhancement of visible light absorption,and an improvement of photoinduced charge separation as well as the photo-stability given by the composite heterojunction.This work shows a viable strategy to design the heterojunction with special morphology for the efficient hydrogen generation by water splitting utilizing solar energy.

Therapeutic sponge prevents postoperative breast cancer recurrence by sustainably dissociating into CD44-targeted nanoplatform

Locoregional recurrence and distant metastasis of breast cancer still pose a significant risk for patients’survival.To address the clinical challenge,functional absorbable sponges(HA-SH/PP-Dox/Lap/COL I(HCNPs))were constructed by biomimetic extracellular matrix of collagen I/hyaluronic acid complex conjugated with doxorubicin/lapatinib(Dox/Lap)-loaded nanoparticles.The HCNPs sponge exhibited excellent clotting ability and blood absorption rate.Worthily,Dox/Lap-loaded nanoparticles were synchronously endowed with a large number of oligo hyaluronic acid segments after degradation,which thus enhanced the ability of targeting into CD44-overexpressed tumor cells.The implantable HCNPs sponge in resected cavity of postoperative 4T1 models inhibited the spread of scattered tumor cells by absorbing the inevitable bleeding.More importantly,CD44 targeted nanoparticle with suitable Dox/Lap proportion continuously released from sponge to kill tumor cells of surrounding HCNPs and those remaining at surgical margin,thus prevented local recurrence as well as distant metastasis.Therefore,the functional HCNPs sponge might provide a safer and more effective strategy for postoperative treatment of cancer.