Periodic Structures Fabricated By STED-DLW Stereolithography: Morphology and Optical Properties

Two-dimensional (photonic antennas) and three-dimensional (photonic crystals) periodic polymer structures were fabricated by STED-DLW stereolithography. Their morphological features were studied using scanning electron microscopy and atomic force microscopy; also their optical properties were investigated by Fourier spectroscopy and confocal microscopy. Keywords: STED-DLW stereolithography, optical properties, luminescent mapping, 3D structure

Localization properties of a one-dimensional tight-binding model with non-random long-range inter-site interactions

We perform both analytical and numerical studies of the one-dimensional tight-binding Hamiltonian with stochastic uncorrelated on-site energies and non-fluctuating long-range hopping integrals . It was argued recently [A. Rodriguez at al., J. Phys. A: Math. Gen. 33, L161 (2000)] that this model reveals a localization-delocalization transition with respect to the disorder magnitude provided . The transition occurs at one of the band edges (the upper one for and the lower one for). The states at the other band edge are always localized, which hints on the existence of a single mobility edge. We analyze the mobility edge and show that, although the number of delocalized states tends to infinity, they form a set of null measure in the thermodynamic limit, i.e. the mobility edge tends to the band edge. The critical magnitude of disorder for the band edge states is computed versus the interaction exponent by making use of the conjecture on the universality of the normalized participation number distribution at transition.Comment: 7 pages, 6 postscript figures, uses revtex

Electroluminescence and optical properties of poly(phenylenevinylene)/J-aggregate composites

Abstract A composite material of poly(phenylenevinylene) (PPV) doped by dye aggregates was prepared. A very efficient and temperature activated energy transfer (ET) from the PPV to the dye aggregates was attributed to F . orster ET accompanied by exciton diffusion. A clear complementary relation between the photoluminescence (PL) and electroluminscence (EL) images was observed for thin (15 nm) PPV-based OLEDs. So-called ''black spots'' in EL become bright ones when the photoluminescence of the same area was excited. This effect was attributed to the presence of an insulating layer between the polymer and aluminium.

TEMPERATURE DEPENDENCE Of THE RADIATIVE LIFETIME OF J-AGGREGATES WITH DAVYDOV SPLITTING OF THE EXCITATION BAND

$^{a}$ I. G. Seheblykin, M. M. Bataiev, M. Van der Auweraer, A. G. Vitukhnovsky, Chem. Phys. Lett. 316, 37-44 (2000)Author Institution: Lebedev Physical Institute; Laboratory for molecular Dynamics and SpectroscopyThe temperature dependence of the radiative exciton lifetime $(\tau_{rad})$ of J-aggregates of $3.3^{\prime}-bis(sulffpropyl)-5.5^{\prime}$-dichloro-9-ethylthiacarbocyanine (THIATS) characterized by a Davydov splitting of the exciton band has been determined over the temperature range from 4.2 to $130K.^{a}$ The Davydov splitting of the exciton was taken into account during the calculation of the coherent length $(N_{c})$ from the values of $(\tau_{rad}$). The dependence of $(\tau_{rad}$) on temperature was analyzed. The $\tau_{rad}$ (T) of J-aggregates of THIATS can be rationalized within the framework of a 1-D excitation model

Reactive Chemical Vapor Deposition Method as New Approach for Obtaining Electroluminescent Thin Film Materials

The new reactive chemical vapor deposition (RCVD) method has been proposed for thin film deposition of luminescent nonvolatile lanthanide aromatic carboxylates. This method is based on metathesis reaction between the vapors of volatile lanthanide dipivaloylmethanate (Ln(dpm)3) and carboxylic acid (HCarb orH2Carb′) and was successfully used in case of HCarb. Advantages of the method were demonstrated on example of terbium benzoate (Tb(bz)3) and o-phenoxybenzoate thin films, and Tb(bz)3 thin films were successfully examined in the OLED with the following structure glass/ITO/PEDOT:PSS/TPD/Tb(bz)3/Ca/Al. Electroluminescence spectra of Tb(bz)3 showed only typical luminescent bands, originated from transitions of the terbium ion. Method peculiarities for deposition of compounds of dibasic acids H2Carb′ are established on example of terbium and europium terephtalates and europium 2,6-naphtalenedicarboxylate

A Kinetic Model for J-Aggregate Dynamics

this paper we make an attempt to construct a selfconsistent model of the 3,3-disulfopropyl-5,5-dichloro-thiacarbocyanine (THIATS) J-aggregate by simultaneous simulation of both the absorption and emission spectra, as well as the luminescence decay profile