Effect of temperature on the optical properties of chemically synthesized CdSe nanostructures

Cadmium selenide (CdSe) nanostructures with different growth temperature viz. 25 °C, 60 °C, 100 °C, 150 °C and 200 °C have been synthesized through chemical route. The results of XRD reveals that as synthesized CdSe nanostructures possess polycrystalline cubic zinc blende structure. The particle sizes obtained from Scherer formula as well as W-H plot and are found to be 2.81 nm and 4.6 nm respectively. The strain induced in the crystal is obtained as −1.8 × 10−3 from the W-H plot. The results of UV–Vis and photoluminescence (PL) spectra show that growth temperature has a significant impact on the optical properties of the synthesized nanoparticles. Both the UV and PL spectra initially show a blue shift with the increase of temperature but after a particular temperature around 100 °C it starts showing red shift. The PL intensity also increases and possesses a maximum at growth temperature 100 °C but afterwards it again decreases at very high temperatures. From the observation of absorption, PL emission along with intensity it has been inferred that growth temperature ranging from 25 °C to 100 °C may be a suitable technique to modulate the optical properties of chemically synthesized CdSe nanoparticles.