O. A. Yeshchenko

Taras Shevchenko National University of Kyiv · Physics Department

The effects of the temperature on the surface plasmon resonance (SPR) in noble metal nanoparticles at various temperatures ranging from 77 to 1190 K are reviewed. A temperature increase results in an appreciable red shift and leads to a broadening of the SPR in the nanoparticles (NPs). This observed thermal expansion along with an increase in the e...

The metal nanoparticle size and shape impact on the plasmonic enhancement of Raman and photoluminescence (PL) spectra of monolayer and few-layer MoS2 decorated with them. The plasmonic enhancement is investigated for Ag nanotriangles (NTs or nanoprisms) of different sizes in comparison to Ag nanospheres (NSs) at room-temperature. After the decorati...

The hydrogels based on cross-linked dextran-graft-polyacrylamide (D-g-PAA) and polyacrylamide (PAA) with different densities of chemical cross-links were synthesized by radical polymerization. They were used as nanoreactors for the photochemical synthesis of silver nanoparticles (AgNPs). The polymer hydrogels and nanocomposites with loaded AgNPs we...

The temperature-driven plasmon-exciton coupling in thermoresponsive dextran-graft-PNIPAM/Au nanoparticle/CdTe quantum dot (D-g-PNIPAM/Au NPs/CdTe QDs) hybrid nanosystem was studied. A significant (0.84 eV) splitting of the absorption peak was observed in the absorption spectrum of the nanosystem, which reflects the fact of formation of plexcitons,...

The label-free detection of biomolecules by means of fluorescence spectroscopy and imaging is topical. The developed surface-enhanced fluorescence technique has been applied to achieve progress in the label-free detection of biomolecules including deoxyribonucleic acid (DNA) bases. In this study, the effect of a strong enhancement of photoluminesce...

Surface texturing of metals and alloys with Ti: Sapphire femtosecond laser has been carried out in air. The peculiarities of surface patterns formed on the surface of noble metals (silver, gold, copper), refractory metal (tungsten) and metal-semiconductor alloy under ultrashort laser pulses have been stud- ied by means of the surface morphology ana...

A reliable photoluminescence (PL) spectroscopy and imaging of biomolecules at room temperature is a challenging and important problem of biophysics, biochemistry, and molecular genetics. A unique effect of strong plasmonic enhancement of the PL by metal nanostructures is one of the most effective approaches for this purpose. The highest enhancement...

This chapter introduces experimental and theoretical results on electromagnetic coupling in arrays of plasmonic gold nanoparticles regularly arranged on a substrate. Near- and far-field coupling leads to non-monotonic shift of the collective surface plasmon mode in the arrays of nanoparticles. Finally, laser driven hybridization of the collective s...

Poly-N-isopropylacrylamide (PNIPAAm) is a biocompatible thermosensitive polymer that is promising for use in nanobiotechnology applications since this polymer has a phase transition temperature (LCST) in the physiological temperature range. LCST can be regulated by changing the hydrophilic-hydrophobic balance of the PNIPAAm-containing macromolecule...

During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterize...

Optical properties of a plasmonic metasurface made of a monolayer of gold nanoparticles in close proximity to an aluminum thin film were studied numerically and experimentally. Extinction spectra of the plasmonic metasurface were studied as functions of the thickness of a dielectric spacer between the monolayer of gold nanoparticles and the aluminu...

Laser induced structural transformations in a dextran grafted-poly(N-isopropylacrylamide) copolymer/Au nanoparticles (D-g-PNIPAM/AuNPs) hybrid nanosystem in water have been observed. The laser induced local plasmonic heating of Au NPs leads to Lower Critical Solution Temperature (LCST) phase transition in D-g-PNIPAM/AuNPs macromolecules accompanied...

The present report concentrates on little known peculiarities of laser-induced periodic surface structures (LIPSS) on metals and alloys formed upon irradiation by linearly polarized Ti/sapphire femtosecond laser pulses with the energy density of 0.17–1.0 J/cm² in air environment. The peculiarities discussed are spontaneous twofold reduction in peri...

The plasmon-enhanced photoluminescence of fullerene C60 thin film has been studied to reveal the dependence of the magnitude of plasmonic field in coupled nanosystem monolayer of gold nanoparticles – fullerene C60film – aluminum film on the thickness of the fullerene spacer in the range of 10–95 nm. The non-monotonic dependence of the photoluminesc...

Hybrid nanosystems consisting of star-like copolymer Dextran-graft-Polyacrylamide in the anionic form (D-g-PAA(PE)), silver nanoparticles (AgNPs), and cisplatin (cis-Pt) have been synthesized in water and characterized by TEM, DLS, FTIR, and UV-Vis spectroscopies. It is shown that cis-Pt forms a complex with carboxylate groups of the polymer. For t...

We study the effects of coupling between plasmonic metal nanoparticles and a thin metal film by using light extinction spectroscopy. A planar monolayer of gold nanoparticles located near an aluminum thin film (thicknesses within the range of 0–62 nm) was used to analyze the coupling between the monolayer and the thin metal film. SPR peak area incre...

Laser-driven hybridization of a collective surface plasmon mode of a monolayer of silver nanoparticles has been studied as a function of irradiation power density. Two collective surface plasmon modes were identified in the spectra, namely, T- and P-modes, associated with the induced particle dipoles parallel and perpendicular to the plane of the l...

Effects of plasmonic coupling between metal nanoparticles and thin metal films separated by thin dielectric film-spacers have been studied by means of light extinction in three-layer planar Au NPs monolayer/dielectric (shellac) film/Al film nanostructure. The influence of coupling on the spectral characteristics of the Au NPs SPR extinction peak ha...

The absorption of light by gold nanoparticles in colloidal water solution has been studied at the simultaneous illumination of nanoparticles by the continuous wave laser beam in dependence on the detuning of laser frequency from the surface plasmon resonance. The appreciable blue shift, broadening, and increase of intensity of the plasmonic absorpt...

The extinction of white light by dense 2D ensemble of gold nanoparticles with size of 22 nm and interparticle distance of 40 nm has been studied at the simultaneous illumination of nanoparticles by the continuous-wave laser beam in dependence of the detuning of laser frequency from the surface plasmon resonance (SPR). The appreciable red shift, bro...

The temperature dependences of energy and width of the surface plasmon resonance were studied for gold nanoparticles with sizes 20–55 nm in silica host matrix in the temperature range 17–915 °С. The increase of temperature leads to appreciable red shift and broadening of the surface plasmon resonance in Au nanoparticles. The obtained dependences we...

The photoluminescence from the fullerene C60thin films on array of the gold nanoparticles was studied at various energies of exciting laser photons. An enhancement of the photoluminescence of C60 film on array of Au nanoparticles was observed. The observed enhancement is due to strong local field of surface plasmon excited in the gold nanoparticles...

For the femto-picosecond time range, we present the results of investigations of induced variations of the optical density ΔD(t), half-width ΔH/2(t), and spectral position of the maximum of the band of surface plasmons (SP) in copper nanoparticles incorporated into SiO2 matrix under the excitation with femtosecond laser pulses. On this basis, a dep...

We report size-dependent melting of spherical copper nanoparticles embedded into silica matrix. Based on the temperature dependence of the surface plasmon resonance energy and its width we observe two distinct melting regimes. For particles smaller than 20 nm the absorption spectrum changes monotonically with the temperature, and this allows us to...

We report size-dependent melting of spherical copper nanoparticles embedded into silica matrix. Based on the temperature dependence of the surface plasmon resonance energy and its width we observe two distinct melting regimes. For particles smaller than 20 nm the absorption spectrum changes monotonically with the temperature, and this allows us to...

ZnAs2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence spectra of ZnAs2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands which demonstrate the blue shift from the line of free exciton in...

Copper nanoparticles have been grown in silica matrix by annealing of the sol-gel prepared porous matrix impregnated with the copper nitrate. The annealing has been performed in air, successively in air and hydrogen, and in hydrogen. Cu nanoparticles in size range of 2-65 nm have been grown depending on annealing conditions. Annealing in air result...

CdP(4) nanoclusters were fabricated by incorporation into the pores of zeolite Na-X and by deposition of the clusters onto a quartz substrate using the laser ablation-evaporation technique. Absorption and photoluminescence (PL) spectra of CdP(4) nanoclusters in zeolite were measured at temperatures 4.2, 77, and 293 K. Both absorption and PL spectra...

CdP2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence (PL) spectra of CdP2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands blue shifted with respect to bulk crystal. We performed the cal...

ZnAs2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence spectra of ZnAs2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands which demonstrate the blue shift from the line of free exciton in...

Nanoparticles of the II V semiconductor (ZnP2) were prepared and investigated. ZnP2 nanoparticles were incorporated into zeolite Na X matrix. Absorption, diffuse reflection (DR) and photoluminescence (PL) spectra of ZnP2 nanoparticles were measured at the temperature of 77 K. Five bands B1 B5 are observed in both the DR and PL spectra demonstrating...

For the first time nanoparticles of CdP2 and CdP4 semiconductors were prepared and studied. The nanoparticles were prepared by incorporation into zeolite Na-X matrix. Absorption and photoluminescence (PL) spectra of CdP2 and CdP4 nanoparticles were measured at the temperature of 77 K. Two bands were observed in both the absorption and PL spectra of...

Excitonic absorption, reflection and photoluminescence spectra of mixed Zn(P1-xAsx)(2) crystals over the full range of x (0 less than or equal to x less than or equal to 1) and Zn1-xCdxP2 crystals at 0 less than or equal to x less than or equal to 0.05 have been studied at low temperatures (1.8 K). The decrease of the energy gap in Zn(P1-xAsx)(2) a...

Excitonic absorption, reflection and photoluminescence spectra of mixed Zn(P1-xAsx)2 crystals over the full range of x ( 0 ? x ? 1) and Zn1-xCdxP2 crystals at 0 ? x ? 0.05 have been studied at low temperatures (1.8 K). The decrease of the energy gap in Zn(P1-xAsx)2 at the increase of x occurs slightly sublinearly. The rydbergs of excitonic series i...

Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed Zn(P1−xAsx)2 crystals have been studied at x=0.01, 0.02, 0.03 and 0.05. Energy gap and rydbergs of excitonic B, C and A-series decrease monotonically with the increase of x. Spectral half-widths of absorption n=1 lines of B and A-series increase monotoni...

Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed Zn(P1−xAsx)2 crystals have been studied at x=0.01, 0.02, 0.03 and 0.05. Energy gap and rydbergs of excitonic B-, C- and A-series decrease monotonically with increasing of x. The spectral half-widths of the absorption n=1 lines of the B- and A-series incr...

A phonon-roton dispersion relation is proposed for the elementary excitations of a quantum biexcitonic liquid in semiconductors. The proposed dispersion relation is used as a starting point for a calculation of the photoluminescence spectrum of the liquid and an analysis of its behavior under variation of the temperature and density of the biexcito...

A phonon–roton dispersion relation is proposed for the elementary excitations of a quantum biexcitonic liquid in semiconductors. The proposed dispersion relation is used as a starting point for a calculation of the photoluminescence spectrum of the liquid and an analysis of its behavior under variation of temperature and density of the biexcitonic...

A problem of the emission (photoluminescence or PL) spectrum of molecular type electron-hole (biexcitonic) Bose liquid in semiconductors is considered. A model of quantum Bose liquid with HeII-like phonon-roton dispersion law is used to calculate the theoretical emission spectrum of such a liquid. At excitation intensities higher than ~1 kW/cm2 and...

Tokunaga et al. [Phys. Rev. B Vol. 59, R7837 (1999)] claim the first successful observation of the inverse exciton M series in the emission spectrum of excitonic molecules. We assert that actually such a series was observed as early as 1989 in the beta-ZnP_2 crystal. We show that the objections of Tokunaga et al. against the biexciton nature of the...

Only very limited number of quantum liquids are known in modern physics of condensed state. The main limitation are the fixed parameters of the real substances. The exciting perspective for further study of the properties of quantum liquids is to use the liquid formed of quasiparticles instead of real chemical substance. One example of such quasisu...

One-photon excitonic absorption spectra of the monoclinic ZnP2 (β-ZnP2) crystals are analysed. There exist four series characterized by the serial law En = Eg — Ry/n2 + Δ/n3 with the same value of energy gap Eg = 1.6026 meV. By variational calculations of the exciton energy dependence on the anisotropy parameter, we conclude an appearance of severa...

Broad T emission band appears in the low-temperature spectra of β - ZnP2 crystals between bands of the free excitons and biexcitons. This band is shown to be due to free ions of excitonic molecule (trions). The dependence of this band intensity IT on the excitation intensity Iexc (IT ∝ Iexc32) proves trion origin of T band. The binding energy of tr...

The ratio of intensities of inverse hydrogenlike series (IHS) luminescence bands which are due to two-electron transitions in an excitonic molecule (EM) have been calculated. The rates of two-photon and two-electron spontaneous transitions in the excitonic molecule have been estimated. Their ratio has been obtained as 0.13. The correlation between...

The dielectric gas-dielectric liquid phase transition in the system of excitonic molecules in β - ZnP2 crystals is considered. The influence of crystal anisotropy is under discussion. The features of β - ZnP2 photoluminescence (PL) spectra under intermediate excitation intensities (Iexc ∼ 103 - - 105W/cm2) at liquid helium temperatures are consider...

The photoluminescence (PL) spectra of the monoclinic modification of the semiconductor crystal ZnP2 (β-ZnP2) are studied under high, intermediate, and low laser excitation intensities at liquid helium temperature. Under high excitation intensities the inverse hydrogenlike M-series was observed. It is symmetrical with the hydrogen-like excitonic ser...