CELES is a freely available MATLAB toolbox to simulate light scattering by many spherical particles. Aiming at high computational performance, CELES leverages block-diagonal preconditioning, a lookuptable approach to evaluate costly functions and massively parallel execution on NVIDIA graphics processing units using the CUDA computing platform. The combination of these techniques allows to efficiently address large electrodynamic problems (>10 4 scatterers) on inexpensive consumer hardware. In this paper, we validate near-and far-field distributions against the well-established multi-sphere T -matrix (MSTM) code and discuss the convergence behavior for ensembles of different sizes, including an exemplary system comprising 10 5 particles.

Discrete random media have been investigated extensively over the past century due to their ability to scatter light. Even so, the link between the three-dimensional (3D) spatial distribution of the scattering elements and the resulting opacity is still lively debated to date due to different experimental conditions, range of parameters explored, or sample formulations. On the other hand, a unified numerical survey with controlled parameters has been impractical up to date due to the sheer computational power required to address samples with representative size. In this work, we exploit a graphics processing unit implementation of the T -matrix method to investigate the complete range of particle volume concentration and packing-induced spatial correlations, allowing us to reveal and elucidate a twofold role played by spatial correlations in either enhancing or suppressing opacity. By applying these findings to the illustrative case of white paint, we determine the optimal combination of density and spatial correlations corresponding to the highest opacity.

We investigated the optoelectronic properties of solution processed organic light emitting diodes (OLEDs) as a function of their active layer thickness. By using a horizontal dipping technique and by accelerating the coating bar during wet film deposition, we fabricated OLED arrays with different emission layer thicknesses but identical process records in a single process step. The comparison of the optoelectronic device parameters allows for conclusions on injection limitation, the optimization of the layer thickness, and, in conjunction with optical simulations of the weak cavity effect, to promote a deeper understanding of the emission profile. To show the universality of this method, we investigated purely polymeric emitters, blends of polymers and small molecules as well as all-small molecule material systems.

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To allow a greater acceptance in the display and lighting markets, organic lightemitting diode (OLED) technology is currently the subject of intensive research efforts aimed at manufacturing cost-effective devices with higher efficiencies. In this regard, strategies matured in the field of photonics and nanophotonics can be applied for photon management purposes to improve the outcoupling of the generated light and to control the emission pattern. In this review, we report on the recent experimental and numerical advances to pursue those goals by highlighting the example of bottom-emitting devices. The cases of periodical microand nanostructures, as well as of stochastic ensembles that can be easily implemented using printing techniques, are covered herein. It is shown that beyond the sole optical properties, such additional elements can simultaneously improve the electrical characteristics of solutionprocessed OLEDs, and thus enable an optimization of the devices at different levels. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.