Nonlinear optical properties of hybrid associates of Ag2S quantum dots with erythrosine molecules

Decreasing in the self-defocusing threshold at wavelength of 532 nm using 10 ns pulses of Nd:YAG laser second harmonic radiation for hybrid associates of Ag2S (2.0 nm) quantum dots (QDs) with erythrosine molecules (Ery) was shown with use the Z-scan method. The obtained result is attributed to the manifestation of hybrid properties due to the interaction of QDs and Ery molecules in associate. It can be explained using the data on the hybrid associates spectral-luminescent properties. The hybrid association with Ery molecules blocks Ag2S QDs IR luminescence under excitation with radiation from the region of dye absorption. Based on the absence of noticeable changes in the luminescence lifetime in the nanosecond range, as well as position of HOMO–LUMO dye states with respect to the size quantization states of Ag2S QDs, it was concluded that electron is rapidly transferred from Ery to the size quantization states in the conduction band. It leads to change the degree of QDs band filling.