Microwave assisted synthesis of CdS quantum dots in DMSO

Abstract

There are many research studies investigating the wide range of application of cadmium sulfide (CdS) nanoparticles. By limiting the size of the nanoparticles to smaller than Borh radius, the quantization of the energy levels to discrete values causes the quantum confinement effect. The most remarkable feature of the quantum dots is the phenomena called multiplication by absorption of a single photon. Quantum dots of CdS prepared as aqueous sols have been reported to undergo photooxidation. Therefore, it was a challenge to synthesize CdS quantum dots in dimethyl sulfoxide (DMSO). This study shows that microwave radiation can affect CdS nanoparticles growth, since DMSO can act as a source of S2- ions. The absorption onsets of the synthesized colloids are determined to be 395, 403 and 470 nm, for non-treated, pre-treated by microwave and post-treated colloids, respectively. The sizes of the nanoparticles were calculated by the effective mass model to be 3.01, 3.21 and 4.84 nm which was affirmed by transmission electron microscopy analysis.