This paper describes issues related to the packaging of a fiber coupled optoelectronic module intended as a current source for pulse-driven Josephson arrays, operating at cryogenic temperatures. The ...module consists of flip-chip bonded photodiodes on a silicon carrier with adhesively bonded optical fiber components in a compact package. Optical and thermomechanical simulations were performed, showing that the needed functionality can be achieved, with optical coupling efficiency above 90% for fiber-chip misalignments up to 40 μm, and that the thermomechanical stresses can be reduced by controlling of the adhesive bonding process.
We investigate the potential of different types of micro-textured foils applied on top of solution-processed solar cells in superstrate configuration, for the purpose of improved device performance. ...Both organic as well as perovskite solar cells are included. The results based on numerical simulations show that application of the micro-textured foils can significantly improve the short-circuit current density in both types of solar cells, especially if the corner cube texture is employed. Further on, we test the applicability of the micro-textured foil on an example fabricated organic solar cell. In this case, however, substantial optical losses are discovered due to the limited device area. Using numerical simulations, we evaluate these losses and determine the minimal device area that would be required to avoid them. Finally, we show how to predict the actual performance of the characterized organic cell, as is expected to be achieved in realistic up-scaled PV module application.
We present the design of discrete out-of-plane coupling components featuring a micromirror for 90° beam deflection in multimode optical interconnections at the printed circuit board level. We ...investigate the Goos-Hanchen shift that occurs upon total internal reflection at a 45° micromirror and assess the influence of applying a metal reflection coating on the micromirror as well as the tolerance for mechanical misalignments using nonsequential ray tracing simulations. Finally, we compare the simulated performance with experimental measurements on out-of-plane coupling components prototyped with deep proton writing.
In this study, the performance of organic solar cells (OSCs) utilizing poly(3-hexylthiophene):(6, 6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM) material was investigated. The research employed ...optical and electrical modeling techniques, using the finite element method (FEM). The study explored the impact of varying the thickness of the active layer, consisting of P3HT: PCBM, as well as the influence of first-order recombination on the performance of organic solar cells (OSCs). The OSCs were constructed using a systematic structure of ITO / PEDOT PSS / P3HT: PCBM (with varying thickness) / Ca / Al. Optical simulations were employed to determine an optimal structure that enhances the absorption of light in the vicinity of the P3HT:PCBM active layer. Additionally, the distribution of electrons and holes within the active layer was investigated in the presence of first-order recombination effects. This increased absorption layer subsequently improved the electrical properties of the devices. The electrical investigation involved analyzing J-V curves under both illuminated and dark conditions. From these curves, key parameters such as short-circuit current density (Jsc), fill factor (FF), open voltage (Voc), and power conversion efficiency (PCE) were extracted. These measurements were performed under 100 mw/cm2 of Air Mass (A.M.) 1.5 Global solar conditions. The results revealed a notably high power conversion efficiency of 3.15 % for an active layer with a thickness of 200 nm.
In this introductory paper I will first go back in history and endeavor to explain in simple terms, with the support of optical diffraction experiments, just how X-ray fiber diffraction pictures lead ...Watson and Crick to discover the DNA double helix. Second I will present the geometrical and chemical structures of the molecule, the “hardware of life”, emphasizing in some detail the nature of the hydrogen bonding in the Watson–Crick (WC) base pairs A–T, G–C formed by the natural bases of the genetic alphabet. I will then discuss a class of twelve artificial analogues to these bases, some of which have been successfully synthesized by organic chemists by rearranging the pattern of hydrogen bonds of the base pairs. Adopting the perspective of theoretical computer science and error-coding theory, I will finally present DNA as the “software of life”, by discussing Mac Dónaill’s recent interpretation of the optimality of the natural genetic cipher as compared to other possible alphabets selected from the artificial analogues.
Ultrathin nanocomposite films of nitrobenzene on silicon were analyzed by Infrared Spectroscopic Ellipsometry (IRSE), X-ray reflectivity (XRR) and X-ray standing waves (XSW) before and after ...evaporation of gold. Infrared Spectroscopic Ellipsometry measurements were performed for identification of adsorbates and for investigation of the molecular orientation. Results for film thickness were correlated with XRR measurements. Further, XSW measurements of elements incorporated in nitrobenzene (C, N, and O) were performed with soft X-rays. The combination of the different methods allowed to confirm a model for the electrochemically deposited nitrobenzene films before and after gold evaporation. The characterization by XRR and XSW scans using hard X-rays showed that gold had penetrated into the nitrobenzene film and thus changed density and optical properties of this layer significantly. A depth profile correlated to the electron density is deduced from the XRR measurements. This profile allows to localize—in vertical direction—gold islands within the composite film.
PV Optics is an optical design package that was developed about a decade ago and has been extensively used since then for design of c-Si, and multijunction a-Si solar cells by researchers and ...engineers. However, this software did not have the capability to include the front metallization into the device structure. We have now developed version 3.0 of PV Optics, which overcomes this limitation and can be used for most of the current electrode designs for crystalline Si solar cells. A summary of this addition along with the results of a detailed study of the effect of front electrode architecture on the performance of (100) textured monocrystalline cells have been presented here.
Two extensions of weighted index method are presented in order to calculate the splitting of degeneracy for non-circular vertical-cavity surface-emitting lasers. Both of them automatically satisfy ...which transverse optical modes split, and give a reliable approximation for the resonant frequencies, threshold gains and confinement factors. The intuitive effective radius method traces back the splitting for different effective aperture radii which are defined according to the transverse intensity distributions. The hybrid analytical axial and numerical lateral method is more precise from a mathematical point of view, and provides the mode patterns as well as the optical data.
PDF
