Formation of hybrid nanostructures based on Zn0.5Cd0.5S quantum dots and silver nanoparticles for nonlinear optical applications in the near ultraviolet

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The goal of this study was to establish optimal conditions for the formation of hybrid nanostructures based on quantum dots and metal nanoparticles with a nonlinear optical response in the near ultraviolet. The relevance of this study is confirmed by the need to create passive devices for controlling the parameters of laser radiation in the presence of semiconductor colloidal quantum dots (QDs) and plasmonic nanoparticles (NPs). Manifestations of interaction in the nonlinear optical response of Zn0.5Cd0.5S QDs and spherical Ag NPs (10 nm) in the field of laser pulses of 10 ns duration at a probing radiation wavelength of 355 nm have been established using the Z-scan method. Manifestations of the formation of hybrid nanostructures have been established using transmission electron microscopy and optical absorption and luminescence spectroscopy. The interaction of colloidal QDs and NPs was manifested as the recombination luminescencequenching of the former with a peak at a wavelength of 450-480 nm. For ensembles of colloidal Zn0.5Cd0.5S QDs with an average size (2.0, 2.2, 2.4 nm), nonlinear refraction (defocusing) of 10 ns laser pulses in the near ultraviolet (355 nm) was established, the coefficient of which increased with increase in QDs. It has been established that during the interaction of Zn0.5Cd0.5S QDs with Ag NPs, the suppression of nonlinear refraction was observed against the background of a twelvefold increase in the nonlinear absorption coefficient. It was concluded that the most probable reason for the observed changes in the nonlinear optical response is the polarizing effect of plasmonic Ag NPs