Surface Plasmon Enhanced Photoluminescence of Rhodamine 6G on Au Nanoparticles 2D Array: Temperature Effects

Influence of temperature on the photoluminescence of rhodamine 6G deposited on 2D array of the gold nanoparticles was studied in the temperature range 78–278 K. The factor of surface plasmonic enhancement of rhodamine luminescence was found to decrease monotonically with increasing temperature. Electron-phonon scattering and thermal expansion of the gold nanoparticles were considered as two competing physical mechanisms of the temperature dependence of plasmonic enhancement factor. The calculations showed the significant prevalence of the electron-phonon scattering that causes the temperature induced decrease of plasmonic enhancement of rhodamine 6G luminescence observed

Surface Plasmon Enhanced Photoluminescence of Rhodamine 6G on Au Nanoparticles 2D Array: Temperature Effects

Influence of temperature on the photoluminescence of rhodamine 6G deposited on 2D array of the gold nanoparticles was studied in the temperature range 78–278 K. The factor of surface plasmonic enhancement of rhodamine luminescence was found to decrease monotonically with increasing temperature. Electron-phonon scattering and thermal expansion of the gold nanoparticles were considered as two competing physical mechanisms of the temperature dependence of plasmonic enhancement factor. The calculations showed the significant prevalence of the electron-phonon scattering that causes the temperature induced decrease of plasmonic enhancement of rhodamine 6G luminescence observed

Optical Properties of Multilayered Metal–Dielectric Structures Containing Silver Nanoparticles

In this paper we report on fabrication and optical properties of metal-dielectric nanostructures consisting of stacked monolayers of silver nanoparticles. The extinction spectra of the nanostructures were studied as a function of the angle of incidence and polarization state of the incident light. Two collective surface plasmon modes, namely T and P, associated with particle dipoles parallel and perpendicular to plane of the layer were identified for a single monolayer of the particles. The extinction bands of T and P modes exhibit different intensity and frequency dependences on the angle of incidence. More pronounced angular dependences for P mode band indicate the stronger coupling of dipoles for P mode than for Tone. A new N mode was observed for the structures comprising three nanoparticle layers. This new mode originated from surface plasmon coupling between adjacent layers

Optical Properties of ZnP2 Nanoparticles in Zeolite

We report that for the first time the nanoparticles of II-V semiconductor (ZnP2) were prepared and studied. ZnP2 nanoparticles were prepared by incorporation into zeolite Na-X matrix. Absorption, diffuse reflection (DR) and photoluminescence (PL) spectra of the ZnP2 nanoclusters incorporated into the supercages of zeolite Na-X were measured at the temperature 77 K. Five bands B1-B5 are observed in both the DR and PL spectra demonstrating the blue shift from the line of free exciton in bulk crystal. We attribute the B1-B5 bands to some stable nanoclusters with size less than the size of zeolite Na-X supercage. We observed Stokes shift of the PL bands from the respective absorption bands. The nonmonotonic character of its dependence on the cluster size can be explained as the result of competition of the Frank-Condon shift and the shift due to electronic relaxation.Comment: Submitted to Microporous and Mesoporous Material

Excitons and Excitonic Molecules in Mixed Zn(P1−xAsx)2Zn(P_{1-x}As_{x})_{2} Crystals

Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed $Zn(P_{1 - x}As_{x})_{2}$ crystals were 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 at the increase of $x$. Spectral half-widths of absorption $n = 1$ lines of B and A-series increase monotonically at the increase of $x$ due to fluctuations of crystal potential. Emission lines of excitonic molecules were observed in photoluminescence spectra of $Zn(P_{1 - x}As_{x})_{2}$ crystals. Binding energy of molecule increases at the increase of $x$ that is due to the decrease of the electron-hole mass ratio.Comment: 10 pages, 7 figures, paper submitted to Physica B: Condensed Matte

Optical Properties and Structure of Most Stable Subnanometer (ZnAs2)n Clusters

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 bulk crystal. We performed the calculations aimed to find the most stable clusters in the size region up to size of the zeolite Na-X supercage. The most stable clusters are (ZnAs2)6 and (ZnAs2)8 with binding energies of 7.181 eV and 8.012 eV per (ZnAs2)1 formula unit respectively. Therefore, we attributed two bands observed in absorption and PL spectra to these stable clusters. The measured Raman spectrum of ZnAs2 clusters in zeolite was explained to be originated from (ZnAs2)6 and (ZnAs2)8 clusters as well. The PL spectrum of ZnAs2 clusters produced by laser ablation consists of a single band which has been attributed to emission of (ZnAs2)8 cluster.Comment: Article accepted for publication in Physica B: Physics of Condensed Matte

Temperature dependence of the surface plasmon resonance in silver nanoparticles

The temperature dependences of energy and width of the surface plasmon resonance were studied for silver nanoparticles with sizes 24 nm and 60 nm in silica host matrix in the temperature range of 17—700° C. The temperature increase leads to red shift and broadening of the surface plasmon resonance in Ag nanoparticles. The obtained temperature dependences were analyzed within the framework of theoretical model considering the thermal expansion of a nanoparticle, the electron-phonon scattering in the nanoparticle and the temperature dependence of dielectric permittivity of the host matrix. The thermal expansion was shown to be the main mechanism responsible for the temperature induced red shift of the surface plasmon resonance in silver nanoparticles. Meanwhile, the increase of electron-phonon scattering rate with increasing temperature was shown to be the dominant mechanism of the surface plasmon resonance broadening in the silver nanoparticles