Papers by Author: Tansir Ahamad

Abstract: Two different batches of Gallium (III) sulphide nanocrystals, (α-Ga₂S₃)1 and (α-Ga₂S₃)2 were synthesized at room temperature by the reaction of Gallium (III) chloride with sodium thiosulphate in water for 10 and 20 min respectively. The resultant nanoparticles were characterized by different spectroscopic techniques. TEM micrographs showed well-defined, close to hexagonal particles, and the lattice fringes in the HRTEM images confirmed their nanocrystalline nature. The sizes of (α-Ga₂S₃)1 and (α-Ga₂S₃)2 were 12 and 35 nm respectively with similar morphologies. Optical band gap energies (3.43 eV/3.41 eV) and photoluminescence peaks 635/641 nm (red shift) and 414/420 nm (blue shift) of the synthesized α-Ga₂S₃ nanocrystals suggest that they may be promising photocatalysts. Raman spectra for the α-Ga₂S₃, shows very sharp bands at 119, 135 and 148 cm^-1 due to Ga-S₂ scissoring.

Abstract: Polymeric ligand (TSCF) have been synthesized via polycondansation of thiosemicarbazide with formaldehyde and its polymer metal complex [TSCF-Cd (II)] has been prepared with Cd (II) ion. Two different batches of CdS chalcogenide, semiconductor nanocrystals have been synthesized by hydrothermal treatment of TSCF-Cd (II)] using a glass Q tube reactor at 200 °C and 250 °C, and marked as (CdS)₁ and (CdS)₂ respectively. The resultant nanocrystals were characterized by a variety of methods for thier physochemcial properties. The TEM micrographs showed well-defined, close to hexagonal particles, and the lattice fringes in the HRTEM images confirmed their crystalline nature. The sizes of (CdS)₁ and (CdS)₂ were 40 and 50 nm respectively but their morphologies were similar. The optical band gap energies (2.52 eV/ 2.48 eV) and photoluminescence peaks (532/534 nm) of the synthesized CdS nanocrystals suggest that they can be promising photocatalysts. The conductivities and the dielectric constants of the CdS nanocrystals were also studied and the activation energy value of (CdS)₁ and (CdS)₂ nanocrystals were found to be 0.64 eV and 0.70 eV.