Photoluminescent and nonlinear optical properties of aqueous synthesised Cd0.6Zn0.4Te nanocrystals in different temperatures

Abstract

In this Letter, Cd0.6Zn0.4Te nanocrystals were synthesised in aqueous solution, in presence of short-chain thiol thioglycolic acid (TGA) as stabiliser. The samples have been characterised by X-ray diffraction, which confirmed that the alloyed nanocrystals were formed and crystal structure is FCC. The synthesis temperature effect on linear optical properties of the nanocrystals has been studied by room temperature UV-vis absorption and photoluminescence (PL) spectroscopy. It can be observed as a red shift in emission and absorption peaks by increasing the synthesis temperature. All obtained samples display a narrow PL and sharp absorption spectra because of the monodispersed distribution. Nonlinear indices of Cd0.6Zn0.4Te nanocrystals were defined by the z-scan technique using continuum wave (CW) He–Ne laser (λ=632.8 nm). The results reveal that these nanoparticles exhibit strong nonlinear optical (NLO) effect such as self-defocusing and two-photon absorption. The z-scan results show that by increasing the synthesis temperature, the nonlinear coefficients were reduced.