SYNTHESIS OF HIGH-LUMINESCENCE CdSe QUANTUM DOTS AT VARIOUS TEMPERATURES

The aim of this paper is to investigate the effect of temperatures on the optical properties of CdSe quantum dots (QDs). High-luminescence CdSe QDs were synthesized using wet chemical method via thermal decomposition reaction of organometallic cadmium and selenium as precursors in a hot solvent mixture. Cadmium precursor was prepared in the three-neck flask with the mixture of CdO, 1-octadecene and oleic acid as a stabilizer. 1 mL of selenium precusor which was prepared earlier was quickly injected into the flask at the temperature between 260 o C to 310 o C. CdSe quantum dots were grown for 45 seconds and then immediately collected. The resulting QDs were isolated by centrifugation and redispersed in hexanes. The optical properties of quantum dots were characterized using Photoluminescence spectrometer (PL) and UV-Vis Spectrometer. When the QDs exposed under the UV-lamp, it radiated light from green to red colour, indicating an increment in the size as the growth temperature increased. PL test revealed that the emitted wavelength of QDs were in the range of 500 nm to 650 nm with the narrow peak. UV-VIS spectrometer characterization support the PL characterized about the emission and excitation of electron which contributed the information on energy gap of the QDs. The effect of temperatures on the improvement of the optical characteristics of CdSe QDs will be discussed. Keyword: CdSe quantum dots; photoluminescence; red-shift; absorption; energy gap;