The temperature dependences of the energy and the width of a surface plasmon resonance are studied for copper nanoparticles 17-59 nm in size in the silica host matrix in the temperature interval 293-460 K. An increase of the temperature leads to the red shift and the broadening of the surface plasmon resonance in Cu nanoparticles. The obtained dependences are analyzed within the framework of a theoretical model considering the thermal expansion of a nanoparticle, the electron-phonon scattering in a nanoparticle, and the temperature dependence of the dielectric permittivity of the host matrix. The thermal expansion is shown to be the main mechanism responsible for the temperature-induced red shift of the surface plasmon resonance in copper nanoparticles. The thermal volume expansion coefficient for Cu nanoparticles is found to be size-independent in the studied size range. Meanwhile, the increase of the electron-phonon scattering rate with the temperature is shown to be the dominant mechanism of the surface plasmon resonance broadening in copper nanoparticles.K e y w o r d s: surface plasmon resonance, copper nanoparticles, temperature-induced effects

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Anomalous temperature dependence of surface plasmon enhanced photoluminescence from copper nanoparticles embedded in a silica host matrix has been observed. The quantum yield of photoluminescence increases as the temperature increases. The key role of such an effect is the interplay between the surface plasmon resonance and the interband transitions in the copper nanoparticles occurring at change of the temperature. Namely, the increase of temperature leads to the red shift of the resonance. The shift leads to increase of the spectral overlap of the resonance with photoluminescence band of copper as well as to the decrease of plasmon damping caused by interband transitions. Such mechanisms lead to the increase of surface plasmon enhancement factor and, consequently, to increase of the quantum yield of the photoluminescence. V C 2014 AIP Publishing LLC. [http://dx.

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We established that metal-dielectric nanostructures (consisting of three stacked monolayers of silver nanoparticles incorporated into polymer cross-linked film) can demonstrate three different surface plasmon collective modes. The modes were detected when the extinction spectra of the nanostructures were studied as a function of the incident angle and polarization of the incident light. Two previously known surface plasmon collective modes, namely T and P, associated with particle dipoles parallel and perpendicular to plane of the layer were identified for the polymer films containing one, two, and three monolayers of the particles. The extinction bands of T and P modes exhibited different intensity and frequency dependences on the angle of incidence. More pronounced angular dependences for P mode band indicated the stronger coupling of dipoles for P mode than for T one. A new N mode was observed for the structures consisting of three nanoparticle layers. This mode originated from surface plasmon coupling between adjacent layers. The additional mode significantly increases amount of information that can be obtained from optical response of the nanostructures.

Metal/semiconductor (Au/CdS) nanocomposites were synthesized in the solution of branched D-g-PAA polymer. TEM and DLS of Au/CdS/D-g-PAA nanocomposites revealed complicated nanocomposite structure consisting of the Au nanoparticles (NPs) of 6 nm in size surrounded by small CdS NPs with size of 3 nm. These nanocomposites formed the aggregates-clusters with average size of 50–800 nm. Absorption spectra of Au/CdS nanocomposites consist of the bands of excitons in CdS NPs and surface plasmons in Au ones. The surface plasmon band of gold NPs is red shifted and broadened in Au/CdS/D-g-PAA nanocomposites comparing to the one of Au NPs in Au/D-g-PAA proving the fact of close location of CdS and Au NPs in the synthesized Au/CdS/D-g-PAA nanocomposites. The PL spectra of Au/CdS nanocomposites originate from the radiative transitions in excitons in CdS NPs. The 4-fold increase of intensity of free exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA that is due to PL enhancement by local field of surface plasmons of Au NPs. Also, the 12-fold decrease of intensity of localized exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA. Most probably, it is due to passivation of the surface of CdS NPs carried out by the Au ones.

Precise control of photoluminescence enhancement and quenching of semiconductor quantum dots using localized surface plasmons in metal nanoparticles