Effect of Growth Time on Optical Properties of CdSe Nanocrystals

Abstract

In the present work, the main objective was to investigate the effect of reaction time on optical properties of CdSe nanocrystals. Cadium Selenide has been hailed as one of the most exciting materials for photovoltaic devices. CdSe nanocrystals were synthesized via hydrothermal route with three different reaction times 3 hrs [S1], 5 hrs [S2] and 7 hrs [S3]. Samples were characterized by X-ray powder diffraction (XRD), UV-VIS spectroscopy and Fourier Transform Infra-red spectroscopy. The optical properties of the as prepared samples were investigated by UV-VIS spectroscopy which reveals that the band gap of as prepared samples has been changed with reaction time. The FTIR spectra of samples demonstrate the presence of similar function groups in all three samples. Size of nanocrystals obtained from XRD data is approximately 3 nm, whereas that calculated by UV-Vis analysis is 2 nm. With growth time, size of quantum dots changes hence their optical parameters also change with growth time. The results demonstrate that the reaction time play an important role on the formation of CdSe nanocrystals.