SYNTHESIS AND CHARACTERIZATION OF CdTe NANOPARTICLES BY SONOCHEMICAL METHOD IN AQUEOUS SOLUTION

Namen magistrskega dela je bil sintetizirati nanodelce kadmijevega telurida (CdTe) s sonokemijsko metodo v vodnem mediju, ki jih uporabljajo v fotonapetostnih sistemih, optičnih napravah in pri zgodnjem odkrivanju ter zdravljenju rakastih obolenj. Kot izhodne snovi smo uporabili kadmijev sulfat hidrat (CdSO4•8/3H2O), kadmijev klorid (CdCl2) in elementarni telur (Te) v prahu. Kot topilo smo uporabili 5 in 10 M vodno raztopino natrijevega hidroksida (NaOH) in 0,05 M raztopino EDTA. Sintezo smo izvajali z ultrazvočno aparaturo visoke intenzitete (Sonics & Materials VCX600, 20 kHz, 80 W/cm2, 1cm2, titanova direktna imerzijska sonda). Kvalitativno karakterizacijo vzorcev in ocenitev velikosti nanodelcev smo izvedli s pomočjo rentgenske praškovne difrakcije (XRD). Morfologijo nanodelcev smo proučili s pomočjo transmisijske elektronske mikroskopije (TEM). Zanimale so nas tudi spremembe v fizikalnih in kemijskih lastnostih pripravljenih nanodelcev CdTe ob povišanju temperature, zato smo opravili tudi termične analize (TGA, SDTA). Rezultati so pokazali uspešnost sonokemijske metode pri pripravi nanodelcev kadmijevega telurida. Sinteze smo uspešno izvedli na dva načina z uporabo različnih kemikalij in s spreminjanjem reakcijskih pogojev. Ocena velikosti nanodelcev po Scherrer—jevi metodi je pokazala, da so bili nanodelci velikosti med 8,0 in 12,8 nm, kar je precej manjše od velikosti delcev CdTe, pridobljenih s klasičnimi metodami. Morfologija nanodelcev je s TEM pokazala aglomerirane produkte kubične strukture.The aim of my master paper was to synthesize cadmium telluride (CdTe) nanoparticles by sonochemical method in aqueous solution, which are used by the photovoltaic systems, optical devices, early detection and therapy of cancer. Cadmium sulphate hydrate (CdSO4•8/3H2O), cadmium chloride (CdCl2) and elementary telur (Te) were used as reagents and 10 M aqueous solution of sodium hydroxide (NaOH) and 0,05 M of EDTA solution were used as solvents. The synthesis was carried out on the basis of high-intensity ultrasound (Sonics & Materials VCX600, 20 kHz, 80 W/cm2, 1cm2, titanium direct immersion horn). The qualitative characterization and estimation of nanoparticles size were carried out by using X−ray powder difraction (XRD). The morphology of nanoparticles was analysed by transmission electron microscopy (TEM). We were also interested in the changes of physical and chemical properties of the prepared CdTe nanoparticles at increased temperature, so thermal analysis (TGA, SDTA) were applied. The results showed evidence of successful use of sonochemical synthesis in producing cadmimum telluride nanoparticles. The syntheses were successfully carried out in two ways by using different chemicals and changing the reaction conditions. X−ray powder difraction showed that the size of nanoparticles was between 8,0 and 12,8 nm, which is much smaller than the CdTe particles produced by classical methods. The morphology of nanoparticles with TEM showed cubic structure of agglomerated products