Investigation of stability and nonlinear optical properties CdSe colloidal nanocrystals

The present paper investigates the linear and nonlinear optical properties of CdSe colloidal nanocrystals which have been prepared by an improved sol-gel green technique. UV-visible absorption spectroscopy and Z-scan technique were used to identify the linear and nonlinear optical properties of CdSe colloidal nanocrystals. The maximum peaks absorption for two samples 2.5 nm and 3 nm were 480 nm and 485 nm, respectively. In addition, the linear absorption coefficients (α), the nonlinear absorption coefficients (β), and the nonlinear refractive index (n2), with their signs and magnitudes for two different sizes of CdSe quantum dots (QDs) were obtained in 15, 25, and 50 mW laser intensities using the single beam Z-scan method by a continuous wave He-Ne laser at 632.8 nm wavelength. Finally, the photostability and chemical stability of the CdSe QDs were studied that have shown high stability of CdSe colloidal nanocrystals. The mentioned nonlinear optical properties have not been reported before.