The decay time of an exciton depends on the coupling between the dipole oscillator and the optical environment in which it is placed. For an organic light-emitting device this environment is determined by the thin-film layer structure. The radiative decay competes with nonradiative decay channels and in this way influences the luminescent efficiency and the external quantum efficiency of the de...

The migration of weakly and non-luminescent (dark) excitons remains an understudied subset of exciton dynamics in molecular thin films. Inaccessible via photoluminescence, these states are often probed using photocurrent methods that require efficient charge collection. Here we probe exciton harvesting in both luminescent and dark materials using a photovoltage-based technique. Transient photov...

Techniques and calculations are presented that give explicit expressions for the over-all performance of a luminescent solar concentrator (LSC) in terms of the intrinsic spectral response and quantum efficiency of its constituents. We examine the single dye (or inorganic ion) LSC with emphasis on the planar geometry. Preliminary data on the degradation of candidate LSC dyes under severe weather...

The electropolymerization behaviors of an electroactive and luminescent compound TCPC as precursor are studied. The resultant electrochemical deposition (ED) films are characterized by cyclic voltammetry (CV), UV-vis, fluorescence spectra, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Under the CV mode with potential range of -0.5 to 0.85 V vs Ag/Ag(+), the coupling rea...

A crossed waveguide grating is presented that can extract the total guided-mode power emitted by a pointsource dipole located in the structure. Results obtained with rigorous numerical simulations are compared with a simple graphic analysis to facilitate an understanding of the far-field radiation pattern of such a luminescent device.

Most recently, stimuli-responsive luminescent materials have attracted increasing interest because they can exhibit tunable emissive properties which are sensitive to external physical stimuli, such as light, temperature, force, and electric field. Among these stimuli, electric field is an important external stimulus. However, examples of electrochromic luminescent materials that exhibit emissi...

− In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a local strain field that is formed by dislocation loop arrays. The dependence of device electrolumi...

We investigated the enhancment of the upconversion luminescence (UCL) of NaYF4:Yb 3 + /Er 3 + co-doped nanocrystals using a 3D plasmonic nanoantenna architecture: disk-coupled dots-onpillar antenna array (D2PA). By optimizing the D2PA structure, we observed a 310-fold UCL enhancement uniformly over a large area and an 8-fold reduction in the luminescence decay time. The enhancement factor is tw...