Search

Red-light-emitting InP/ZnSexS1-x core/shell quantum dots (QDs) were prepared by one-pot synthesis with optimal hydrogen fluoride (HF) treatment. Most of the surficial oxidative species could be removed, and the dangling bonds would be passivated by Zn ions for the InP cores during HF treatment, which would be beneficial to the subsequent ZnSexS1-x shell coating. Three-dimensional time-resolved photoluminescence spectra of the QD samples were analyzed by singular value decomposition global fitting to determine the radiative and nonradiative lifetimes of charge carriers. A proposed model illustrated that the charge carriers in the InP/ZnSexS1-x QDs with interfacial oxidative layer removal would evidently recombine through radiative pathways, mainly from the conduction band to the valence band (lifetime, 33 ns) and partially from the trap states (lifetime, 150 ns). This work offers the important physical insight into the charge carrier dynamics of low-toxicity QDs which have the desired optical properties for optoelectronic applications.

d -Panthenol (provitamin B5) and salt of pantothenic acid are used in many cosmetic and pharmaceutical preparations for their skin emollient, regenerating and hair conditioning properties. The cathodic reduction of d -panthenol and salt of pantothenic acid had been studied by differential pulse voltammetry (DPV) at carbon paste electrode (CPE) and metal oxides modified CPE in the presence of cationic surfactants (stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, dodecyltrimethylammonium chloride), anionic surfactants (sodium dodecyl sulfate, sodium dodecyl ether sulfate, sodium dodecylbenzenesulfonate) and non-ionic surfactants (TritonX-100, Span 60 and Tween 60) micelles. The peak potentials and peak currents have been found to be dependent on the character and concentration of the surfactant. The reduction potential of d -panthenol at a cobalt oxide modified CPE is shifted by 220 mV to more positive potential in the presence of the stearyltrimethylammonium chloride micelle. d -Panthenol and salt of pantothenic acid in commercial cosmetic and pharmaceutical preparations were determined by DPV using a cobalt oxide modified CPE in phosphate buffer (pH 6.08) solution. Comparison with results obtained from the spectrophotometry (SPM) shows good agreement.

The effect of surface plasmon resonance (SPR) on the blinking emission of photoluminescence from noble metal nanostructures still requires further investigation in quantum mechanics and limits their applications. We investigate one photon luminescent emission intermittency of noble metal nanostructures with differently sized sea-urchin-shaped nanoparticles, known as nano-sea-urchins (NSUs). The probability of the “on” process in one photon luminescent emission intermittency of NSUs increases due to the strong electric field of SPR. This mechanism is explained by the reaction potential threshold model we propose here. Furthermore, the ameliorated photoluminescence of NSUs is strong enough to excite waterweed bioluminescence and can act as an in vivo bio-light emitting device, which has potential applications in cytotoxicity, bio-imaging and bio-labeling.