Dmitry A. Videnichev

Optical limiting as result a of photoinduced electron transfer in hybrid systems with CdSe/ZnS quantum dots, C 60 , and Perylene

We investigated the interaction of an intense laser radiation with colloidal solutions containing CdSe/ZnS core shell quantum dots (QDs; mean size 3.4 nm), fullerene C(60), and Perylene. These materials would give rise to the photoinduced electron transfer and charge separation on the QDs and thus the optical limiting effect. Results confirm the intended aim, obtained by means of intermediate metastable products of reversible photochemical reactions, i.e., ion radicals of hybrid systems containing semiconductor nanoparticles.

Stability and optical limiting properties of a single wall carbon nanotubes dispersion in a binary water-glycerol solvent

We report the temporal stability of the dispersion of single-wall carbon nanotubes in a binary solvent “water + glycerol” having eutectic composition (ca. 67% wt.) with sodium dodecylbenzene sulfonate as a dispersant. The system procures good temporal and thermal stability: its absorption spectra demonstrate no changes during one-year storage with temperature spanning −40 to +40 °C. The system provides non-linear optical power limiting of the incident laser radiation (532 nm) in a one-shot and pulse-periodic regimes of its applying.

Comparative studies of optical limiting in fullerene and shungite nanocarbon aqueous dispersions

Optical limiting properties of natural carbon nanoparticles (Shungite carbon) and fullerene aggregates in aqueous dispersions were for the first time studied and juxtaposed. For the picosecond laser pulses both dispersions exhibited comparable optical limiting property, apparently due to nonlinear absorption (mainly TPA). In the domain of the nanosecond laser pulses, nonlinear scattering NLS is thought to be main optical limiting mechanism in the dispersions under study. Shungite carbon dispersion showed stronger optical limiting (being similar to CBS) in visible and IR, which we ascribe to its structure more favorable to the thermal relaxation processes responsible for the NLS mechanism.

Optical limiting of laser radiation and light quenching in colloidal solutions of CdSe/ZnS semiconductor quantum dots and hybrid systems

The photodynamics of power optical limiting is studied in colloidal solutions of quantum dots by exiting the system in the absorption band with 0.4-ns 532-nm pulses. Based on a parallel analysis of the dependence of the nonlinear transmission and luminescence decay kinetics of the investigated solutions, the conclusion is drawn that the main mechanism of the optical limiting of nanosecond laser radiation pulses is light quenching of the so-called dark states in quantum dots. The efficiency of limiting is determined by the dynamics of the population of these states. It is shown that CdSe/ZnS QDs–C60 hybrid system has the same efficiency in both the single-pulse and 10-Hz reptation rate modes.

Solid-phase fullerene-like nanostructures as singlet oxygen photosensitizers in liquid media

Singlet oxygen generation by fullerene and astralen containing surfaces and powders under visible irradiation was studied in water and organic liquids by means of 1Δg state luminescence and chemical scavenger transmittance measurements. The chemical method, pioneered for solid photosensitizers of 102, allowed to measure the singlet oxygen concentration in the aqueous medium down to 108 cm-3. The singlet oxygen sensitizing by the solid-phase fullerene-containing systems was found to be 100 times less effective then by fullerene in solution. The results obtained confirm the applicability of these structures in biology and medicine.

Aggregated inorganic chromophores in polymer matrices for photonics applications

We report on the interrelationship between luminescent, non-linear optical and photo-sensitizing properties of aggregates of inorganic chromophores (PbS, C60, SWCNT, and C60@SWCNT nano-peapods) in presence of polymers against the aggregates defectiveness degree.

Spectral and optical limiting properties of ZnS nano- and bulk crystals

Some features of spectral and non-linear optical properties of ZnS quantum dots stabilized by high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of ZnS composite materials (sols, coatings) in UV spectral region are determined by quantum confinement effect, exhibiting the dependence of the absorption edge of the size of the ZnS nanocrystals.