T. Radhakrishnan

Cadmium ethylxanthate: A novel single-source precursor for the preparation of CdS nanoparticles

CdS nanoparticles capped with tri-n-octylphosphine oxide (TOPO) have been synthesised by a single-source route using cadmium ethylxanthate as a precursor. The nanoparticles obtained show quantum size effects in the optical absorption spectra and the photoluminescence shows an emission maximum that is characteristically red shifted in relation to the band edge. The X-ray diffraction (XRD) pattern shows the material to be hexagonal with a calculated particle size (from the Scherrer equation) of 3.9 nm. The size of the particles is confirmed by the transmission electron microscope (TEM) image, which shows well-defined, spherical particles with an average size of 4.2 nm ± 10%.

Preparation of CdS nanoparticles using the cadmium(II) complex of N,N′-bis(thiocarbamoyl)hydrazine as a simple single-source precursor

CdS nanoparticles have been synthesised by thermolysing Cd(SCNHNH2)2Cl2 in tri-n-octylphosphine oxide (TOPO) at 230°C. The optical properties and structural characteristics of the particles are reported.

Cd(NH2CSNHNHCSNH2)Cl2: a new single-source precursor for the preparation of CdS nanoparticles

Abstract The complex of cadmium with dithiobiurea, [Cd(NH 2 CSNHNHCSNH 2 )Cl 2 ], has been used as a precursor for the synthesis of CdS nanoparticles. The precursor was decomposed in tri- n -octylphosphine oxide to give CdS nanoparticles that show quantum confinement effects with characteristic close to band edge luminescence. The broad diffraction in the XRD pattern and diffused diffraction rings of the SAED pattern are typical of nanometer-sized particles. The particle morphology was found to depend on the temperature of injection of the precursor. Transmission electron microscopy shows irregular non-spherical particles prepared by injection at 150 °C, whilst with injection at 240 °C the particles are formed as spherical aggregates of relatively uniform size (50 nm).

Characterization of polystyrene filled with HgS nanoparticles

A polystyrene (PS)–HgS nanocomposite has been synthesized by first preparing a copolymer of styrene and mercury–acrylamide (5% by weight) and further reaction of it with H2S in chloroform solution. The effect of the HgS nanoparticles on the physical properties of the composite has been studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The glass transition temperature of the composite is 20 jC higher than that of polystyrene. The thermal stability of the composite is higher than that of polystyrene as evidenced by the shift of onset temperature of degradation by 12 jC as measured by TGA. D 2003 Elsevier B.V. All rights reserved.

The synthesis of HgS nanoparticles in polystyrene matrix

A composite of nanodimensional HgS and polystyrene has been prepared by reacting a solution of the copolymer formed from mercury acrylamide and styrene in chloroform solution with H2S. The product shows different colours depending on the amount of H2S used. The composite material has been characterised by UV, PL, TEM, and XRD techniques. The TEM images show particle sizes of less than 12 nm. The band gaps calculated from the optical spectra are higher than that for bulk material as expected for quantum confined materials.

A single-source route to CdS nanorods

We report the preparation of CdS nanorods using a thiosemicarbazide complex of cadmium [Cd(NH2CSNHNH2)2Cl2]. The precursor was decomposed in tri-n-octylphosphine oxide (TOPO) at 280 degrees C to give TOPO capped CdS nanoparticles; nano-dimensional rods of the material are clearly visible in transmission electron microscopy (TEM); the particles have been further characterised by X-ray diffraction (XRD) and selected area electron diffraction (SAED) and optical measurements.

STUDIES OF MICROENVIRONMENTAL EFFECTS ON COMPLEXATION OF POLYMER-BOUND SCHIFF BASES WITH TRANSITION METAL IONS

ABSTRACT A new series of chelating resins were prepared by anchoring Schiff base moieties on lightly cross-linked polyacrylamide. The aldehyde precursors for the synthesis of the Schiff bases were prepared by introducing a substituted azobenzene group into the phenolic aldehydes. All of the polymer-bound Schiff bases effectively coordinate metal ions like Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) from aqueous solutions. The metal ion uptake decreases as the bulkiness of the ligand increases. The pH-dependence of the metal ion uptake was also studied. Tentative geometries are suggested for the complexes from their spectral and magnetic properties.