Radiolytic synthesis and spectroscopic investigations of Cadmium Selenide quantum dots grown in cationic surfactant based quaternary water-in-oil microemulsions

Highly stable spherical shaped and blue photoluminescent cyclodextrin-coated tellurium nanocomposites prepared by in situ generated solvated electrons: a rapid green method and mechanistic and anticancer studies

Highly stable blue photoluminescent tellurium nanocomposites (Te NCs) coated with a molecular assembly of α-cyclodextrin (α-CD) have been prepared by using in situ generated solvated electrons (e_sol^-) in the reaction media. The methodology used is rapid and green as the preparation of colloids was over in a matter of a few seconds and no hazardous agents (reducing or stabilizing) were used. Furthermore, fine control over the size of Te NCs has been demonstrated by simply varying the absorbed irradiation dose. As a matter of fact, the anisotropic property exhibited by tellurium makes it difficult to control the phase and morphology of its nanomaterials. However, unlike the majority of the previous reports, Te NCs formed by the current approach were amorphous and spherical shaped. Another interesting aspect of this work is the cyan-blue photoluminescence (PL) exhibited by the NCs. Systematic photophysical investigations indicated bandgap radiative decay as the origin of photoluminescence. A compositional analysis indicated the presence of Te(0) along with tellurium oxides (TeO_x). TGA studies revealed the formation of a dense coating (∼55%) of α-CD molecules on the NCs. Pulse radiolysis-based studies evidenced the formation of Te-based transients by the solvated electron-induced reaction. Importantly, no interference of α-CD was observed in the kinetics of the transient species. Remarkable concentration-dependent killing was observed only in the case of cancerous cells, while no such trend was seen in normal healthy cells. This is a significant observation that can be utilized to achieve differential toxicity of Te nanomaterials in tumor versus normal cells.

Synthesis of silver nanoclusters by irradiation reduction and detection of Cr3+ ions

Using irradiation technology, the synthesis of silver nanoclusters can be achieved efficiently and green without relying on reducing agents and high energy consumption equipment.

Porous nanostructures of SnSe: role of ionic liquid, tuning of nanomorphology and mechanistic studies

Porous SnSe nanoparticles have been synthesized in imidazolium based RTILviaelectron beam irradiation. RTIL provides a stabilizing environment as well as anin situsource of reducing radicals for the reduction of precursors.

Photoluminescence Studies in II-VI Nanoparticles Embedded in Polymer Matrix

Recently, organic-inorganic hybrid nanocomposite materials have been of great interest for their extraordinary performances due to the combination of the advantageous properties of polymers and the size dependent properties of nanocrystals (NCs). Interaction between the polymer matrix and nanocrystalline fillers produces wonderful features, viz. thermal, magnetic, mechanical, electrical and optical properties to these materials. Modern applications require a new design of responsive functional coatings which is capable of changing their properties in a controlled way. However, the synthesis of II-VI nanoparticles into the polymer matrix of its nanocomposites with adjustable sizes and protected from photo-oxidation is a big challenge to the scientific community. It is difficult to synthesize the highly enhanced luminescence in polymers and its semiconductor nanocomposite systems. Luminescence from the polymer embedded II-VI nanoparticles is greatly enhanced and better stability can be achieved from the composite compared to bulk materials. The formation of nanocomposites can be confirmed by photoluminescence (PL) spectroscopy. It is an important technique for determining the optical gap, purity, crystalline quality defects and analysis of the quantum confinement in these nanocomposite materials. In this paper, we have reviewed the present status of II-VI polymer nanocomposites from the photoluminescence studies point of view. We have also shown the results of the PL of these nanocomposite materials and the results will be compared with the reported literature by other groups.Contents of Paper

Physicochemical investigation of mixed surfactant microemulsions: water solubilization, thermodynamic properties, microstructure, and dynamics

In this contribution, we report on a systematic investigation of phase behavior and solubilization of water in water-in-heptane or decane aggregates stabilized by mixtures of polyoxyethylene (20) cetyl ether (Brij-58) and cetyltrimethylammonium bromide (CTAB) surfactants with varying compositions in conjugation with 1-pentanol (Pn) at fixed surfactant(s)/Pn ratio and temperature. Synergism in water solubilization was evidenced by the addition of CTAB to Brij-58 stabilized system in close proximity of equimolar composition in both oils. An attempt has been made to correlate composition dependent water solubilization and volume induced conductivity studies to provide insight into the solubilization mechanism of these mixed systems. Conductivity studies reveal the ascending curve in water solubilization capacity-(Brij-58:CTAB, w/w) profile as the interdroplet interaction branch indicating percolation of conductance and the descending curve is a curvature branch due to the rigidity of the interface in these systems. The microstructure of these systems as a function of surfactant composition has been determined by dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR) measurements. FTIR study reveals increase and decrease in relative population of bound and bulk-like water, respectively, with increase in Brij-58:CTAB (w/w). DLS measurements showed that the droplet hydrodynamic diameter (Dh) decreases significantly with the increase in Brij-58:CTAB (w/w). Further, the interfacial composition and energetic parameters for the transfer of Pn from bulk oil to the interface were evaluated by the dilution method. Formation of temperature-insensitive microemulsions and temperature invariant droplet sizes are evidenced in the vicinity of the equimolar composition. The results are interpreted in terms of a proposed mechanism.