Designing an Experimentally Feasible Selective Emitter For a Thermophotovoltaic System

More than 60% of the raw energy used in the US is dissipated as waste heat. Thermophotovoltaics (TPV) provide a means to capture this waste heat into electricity. Inefficiencies in TPV systems are due to various loss mechanisms, particularly a lack of spectral matching between the emission spectrum of the emitter and the absorption spectrum of the photovoltaic cell. This study aims to design a simple structure emitting thermal photons mostly at high energies, which could allow for efficient generation of electricity through a photovoltaic cell. Optical data for the different materials obtained using ellipsometry and previous research is incorporated into a nanoHUB tool, known as the Thermophotonic Selective Emitter Simulator (TPXsim), to compute the expected enhancement of the TPV system efficiency. Changes have been made to the TPXsim tool to incorporate customized top dielectric mirror layers, samarium doped glass cavity and bottom metallic back reflectors. It is seen that a TPV system consisting of a rare-earth wafer emitter at 1573 K plus a cold-side rugate filter at 300 K shows an overall efficiency of around 18%. Previous research on emitter designs with top and bottom layers of dielectric mirror is seen to increase this efficiency at a large number of layers while degrading the performance for a small number of layers. Our research shows that using aperiodic customized multilayer structures and metallic back reflectors improves the efficiency over a bare wafer while maintaining the ease of fabrication of the selective emitter

Computational Design for Next Generation Solar Cells

Although photovoltaic technology has improved tremendously over the past several decades, there is still signicant scope for improvements which can be systematically investigated through advanced simulation techniques, particularly in the electromagnetic domain. However, accurately simulating the detailed performance of emerging light trapping and current-harvesting harvesting structures still requires a tremendous amount of detailed calculations. For these reasons, without any simplications, 3-D electromagnetic computation of a single photovoltaic unit cell easily exceeds the computing limit of a single core machine or even that of a computing cluster. Thus, building a more efficient and accurate simulation framework for solar cells can provide a deep understanding of solar cell physics, generate new conceptual designs, and enable breakthrough next generation solar cells

Design parameters of free-form color splitters for subwavelength pixelated image sensors

Summary: Metasurface-based color splitters are emerging as next-generation optical components for image sensors, replacing classical color filters and microlens arrays. In this work, we report how the design parameters such as the device dimensions and refractive indices of the dielectrics affect the optical efficiency of the color splitters. Also, we report how the design grid resolution parameters affect the optical efficiency and discover that the fabrication of a color splitter is possible even in legacy fabrication facilities with low structure resolutions

Efficient Selection of Antibodies Reactive to Homologous Epitopes on Human and Mouse Hepatocyte Growth Factors by Next-Generation Sequencing-Based Analysis of the B Cell Repertoire

: YYB-101 is a humanized rabbit anti-human hepatocyte growth factor (HGF)-neutralizing antibody currently in clinical trial. To test the effect of HGF neutralization with antibody on anti-cancer T cell immunity, we generated surrogate antibodies that are reactive to the mouse homologue of the epitope targeted by YYB-101. First, we immunized a chicken with human HGF and monitored changes in the B cell repertoire by next-generation sequencing (NGS). We then extracted the VH gene repertoire from the NGS data, clustered it into components by sequence homology, and classified the components by the change in the number of unique VH sequences and the frequencies of the VH sequences within each component following immunization. Those changes should accompany the preferential proliferation and somatic hypermutation or gene conversion of B cells encoding HGF-reactive antibodies. One component showed significant increases in the number and frequencies of unique VH sequences and harbored genes encoding antibodies that were reactive to human HGF and competitive with YYB-101 for HGF binding. Some of the antibodies also reacted to mouse HGF. The selected VH sequences shared 98.3% identity and 98.9% amino acid similarity. It is therefore likely that the antibodies encoded by them all react to the epitope targeted by YYB-101