Thermal and structural studies of CdSe nanorods synthesized by solvothermal process

Abstract

CdSe nanorods with wurtzite structure are synthesized by solvothermal process for different reaction time in a mixed solvent of hydrazine hydrate [H6N2O], ammonia [NH3], and de‐ionzed water. Cadmium acetate [Cd(CH3COO)2 · 2H2O] and sodium selenite [Na2SeO3] are precursors used for cadmium and selenium ions, respectively. Structural parameters are obtained using Williamson–Hall plot of the X‐ray diffraction data. Energy dispersive X‐ray analysis measurements show that the nanorods are slightly cadmium rich and stoichiometry improves with reaction time. Field emission scanning electron microscope images show morphological changes in CdSe nanoparticle with reaction time. While particles synthesized for shorter reaction time are mostly spherical and oval shape, longer reaction time results in mostly elongated rod‐shape particles. Thermal stability of the nanorods is studied using thermogravimetric analysis (TGA). All the samples have high thermal stability without significant weight loss up to about 590 °C. The kinetics of thermal decomposition studied using Coats–Redfern method shows that the decomposition follow contracting cylinder model, which assumes that nucleation occurs rapidly on the surface of the cylindrical nanoparticles. Thermodynamic parameters in the decomposition such as activation energy, change in entropy, enthalpy of activation, and Gibbs free energy are also calculated.