Effect of using Different Techniques on Structure and Optical properties of Prepared Nanoparticles CdS

Salma Shaban, K Mahdi
2015 International Journal of Advanced Research in Science, Engineering and Technology   unpublished
Nanoparticles CdS were prepared by using three techniques, firstly super cooling, and the second the liquid-liquid interface reaction and the third capping agent technique. The crystalline size was analyzed by x-ray diffraction data using Scherer method to be about 10 nm obtained from super-cooling and less to about 4nm by using capping agent. The amount of residual strain depends on the method of preparation .The band gap showed a blue shift from the bulk. The main reason for the blue shift
more » ... the quantum dimensional effect of the nanoparticles size according to the method used. KEYWORDS: CBD, Supercooling, Liquid-Liquid Interface I. INTRODUCTION Nanoparticles semiconductor has a special optical and electronic properties that make it very differ from the bulk properties and this give it a great interest in the currently research [1]. When the structure of the semiconductor has a dimension enter in the nanoscale, the optical properties has a new distinguish proper than the bulk especially when the dimension comparable with Bohr radius then the properties show the quantum-size effect (quantum confinement) [2-6], this led to increase the optical band gap and the relation between the optical band gap and the size of nanostructure (size confinement) led to a great application in band gap engineering [7-10]. One of the important application of CdS is in the solar cells, it has a suitable properties that can be used to build a solar cell devices, it has a high photoconductivity gain and its spectral response is in the uv-visible range which make it useful to build visible radiation sensor[ 11,12]. The nanoparticles CdS has a great interest in the currently research because it can be used in fabrication of a single electron transistor and UV light emitting diode [13, 14, 15]. The main problem to prepare nanoparticles is that to prevent the accumulation and aggregation of the particles. There are many methods to prevent this aggregation such as using a super cooling, complex agent, super saturation. In this paper, nanoparticles CdS are prepared using super cooling, liquid-liquid interface reaction and capping agent methods and study its structure and optical properties using X-ray diffraction and UV-visible absorption spectrum. II. EXPERIMENTAL DETAILS A.PREPARATIO OF NANOPARTICLES CdS BY SUPERCOOLING Nanoparticles CdS was prepared from aqueous solution of CdCl2.H2O (0.02 M) as a source of Cadmium, Na2S.9H2O (0.02 M) as a source of Sulphur. The chemical bath is prepared from the solution of CdCl2.H2O and Na2S.9H2O. At the first we dissolve 4.03 gm from CdCl2.H2O in 800 ml of deionized water by using magnetic stirrer till the read of PH-meter stable which indicate that we have homogenous solution. In another beaker we dissolve 5 gm from Na2S.9H2O in 200 ml of deionized water using magnetic stirrer till the read of PH-meter stable which indicate that we have a homogenous solution. Then we cooling the CdCl2.H2O solution using water bath tell the temperature reach to 5 0 C then we added drop by drop Na2S.9H2O solution by using burette to the CdCl2.H2O solution till the last drop is falling then leave the solution under high stirrer and that ow temperature for two hour then filtered and cleaned by deionized water and leave it to dry in oven under 60 0 C for twelve hour. CdCl2.H2O (aq) +Na2S.9H2O (aq) CdS(S) + 2NaCl (aq) +10H2O