Development of greener methodology for the synthesis of CdSe quantum dots and characterization of their thin films

Abstract

Cadmium selenide (CdSe) quantum dots (QDs), being a well established highly luminescent semiconducting optical material, has diverse applications in the recent fields of optoelectronics, light emitting diodes and photo voltaic solar cell, attributed to its tunable band gap as a consequence of their tunable size and shape. Besides having tremendous utility, most of the synthesis routes of CdSe QDs reported, seems to be hazardous. Therefore, in the present study, we are reporting a considerably, greener method to synthesize CdSe QDs by using sodium borohydride, as the reducing agent. The highly stabilized QDs, over a period of one year, were characterized using high resolution transmission electron microscope and powder X-ray diffraction technique. Nanocrystallites with hexagonal and cubic polycrystallinity, exhibiting 3–12 nm size were successfully observed, without using any capping reagent. The UV–visible absorption is also revealing good agreement by showing a blue shift at the range of 450–470 nm. The QDs are further subjected to the fabrication of homogeneous thin films upon a glass template using spin coater. The thin films were further characterized using atomic force microscopy, which showed an average area (root mean square) roughness of 5.7898 nm at 2.53 µm area.