Modeling of thin-film interference filters on structured substrates: microfacet-based BSDF versus ray tracing.

We compare two model approaches for the ray optical description of PV modules with coloring based on an interference layer system on the inside of the cover glass. The light scattering is described by a microfacet-based bidirectional scattering distribution function (BSDF) model on the one hand and ray tracing on the other hand. We show that the microfacet-based BSDF model is largely sufficient for the structures used in the context of the MorphoColor application.

Modeling the optical properties of Morpho-inspired thin-film interference filters on structured surfaces.

We present a method for modeling the optical properties of interference layer systems on structured surfaces as used in the MorphoColor technology for coloring integrated photovoltaic modules. By combining a microfacet-based bidirectional scattering distribution function model with a transfer matrix formalism, we can simulate the spectrally resolved reflection and transmission properties of the system in good agreement with measurement data. To consider the MorphoColor technology in an overall optical system and compare the application on the front side of the module glass with the application in the composite, the model is additionally combined with a formalism called Optical Properties of Textured Optical Sheets.

Double-Mesoscopic Hole-Transport-Material-Free Perovskite Solar Cells: Overcoming Charge-Transport Limitation by Sputtered Ultrathin AlO Isolating Layer.

The electrically insulating space layer takes a fundamental role in monolithic carbon-graphite based perovskite solar cells (PSCs) and it has been established to prevent the charge recombination of electrons at the mp-TiO/carbon-graphite (CG) interface. Thick 1 μm printed layers are commonly used for this purpose in the established triple-mesoscopic structures to avoid ohmic shunts and to achieve a high open circuit voltage. In this work, we have developed a reproducible large-area procedure to replace this thick space layer with an ultra-thin dense 40 nm sputtered AlO which acts as a highly electrically insulating layer preventing ohmic shunts.

Measurement of electron clouds in large accelerators by microwave dispersion.

Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation at high currents. Furthermore, it is difficult to probe their density over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave transmitted over a section of the accelerator and used it to measure the average electron cloud density over a 50 m section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center.