Ternary alloyed Cd0.7Zn0.3Te colloidal quantum dots were synthesized under open atmosphere conditions. The Cd0.7Zn0.3Te quantum dots were characterized under XRD studies, DLS technique and optical absorption measurements. Using tauc and urbach relation the optical energy bandgap and urbach energy were obtained. The intensity depended nonlinear optical parameters of Cd0.7Zn0.3Te quantum dots were determined with Z-scan experimental setup using a green laser source working on continuous wave mode. The nonlinear absorption coefficient β, along with optical limiting capacity of Cd0.7Zn0.3Te quantum dot is investigated through the open aperture set up. The transmittance of Cd0.7Zn0.3Te quantum dot showed a sharp dip at the maximum intensity point of the laser which indicates reverse saturable absorption. The optical limiting threshold value for Cd0.7Zn0.3Te quantum dot was obtained around 4.6 KJ/cm2. The nonlinear refractive index of Cd0.7Zn0.3Te quantum dot is find out using closed aperture set up. The nonlinear refractive index with a negative sign was obtained for the Cd0.7Zn0.3Te quantum dot which is attributed to the self-defocusing phenomena. The nonlinear studies indicate that the sample exhibits good nonlinear properties and find applications in optical limiting materials.

3-MPA capped CdZnTe alloy quantum dots synthesized using Na2TeO3 as the tellurium source under open atmosphere conditions in aqueous medium. The optical and photoluminescence properties of the CdZnTe quantum dots characterized using UV-Visible absorption and Photoluminescence spectrum. An excitonic peak at 527 nm observed in the absorption spectrum. Tauc relation and Urbach relation were employed to find the bandgap energy and urbach energy of the CdZnTe quantum dot. The quantum dot particle size was estimated using the bandgap energy from Tauc plot employing tight binding approximation, which was 4.75 nm. A high intense emission peak at 567 nm obtained in the photoluminescence spectrum. The emission peaks correspond to yellow fluorescence. The CIE chromaticity diagram gives color coordinate at (0.41,0.56) with a color purity of 92%. The high intense yellow fluorescent CdZnTe quantum can placed as potential candidates for fluorescent probes, biolabeling and cell imaging applications.

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