Определение эффективности нейтронного детектора из пластического сцинтиллятора o100?200 мм

Рассчитывается и экспериментально проверяется эффективность детектора. к нейтронам сверхвысоких (десятки и сотни МэВ) энергий

Transparent conductive oxide photonic crystals on textured substrates

Three-dimensional ZnO:Al photonic crystals were fabricated by atomic layer deposition on highly textured substrates. It turns out that these inverted opals consist of a thin intermediate disordered layer close to the textured substrate followed by a highly-ordered photonic crystal layer. The photonic crystals themselves exhibit comparable optical properties to those on planar substrates. (C) 2010 Elsevier B.V. All rights reserved

Directional selectivity and ultra-light-trapping in solar cells

Directional and energy selective optical surface structures attached to solar cells may result in both, enhancement or deterioration of photovoltaic performance of a solar cell. On the one hand, restricting the cell acceptance to the small incidence angle of direct and circumsolar irradiation enhances the maximum path length of the light in a solar cell with Lambertian surfaces even above the Yablonovitch limit (ultra-light-trapping). On the other hand, restrictions to small acceptance angles imply losses of diffuse sunlight, even for perfectly tracked cells. Using temporally resolved solar irradiation spectra, we simulate the enhancement and loss in the annual energy yield of silicon solar cells of various thicknesses. We assume an idealized angular and energy selective filter on top of the Lambertian surface of the absorber and compare the results to a Lambertian surface only. We find a maximum annual gain in the energy density of 32.5% for 1 mu m, and of similar to 10% for 10 mu m and 100 mu m thick perfectly tracked crystalline silicon solar cells. The simulation implies various tracking modes and two different locations. Finally, we introduce two possible realizations of such a filter; a Ru-gate stack and inverted opals. In experimental measurements, we could verify the absorptance enhancement by such a structure applied on top of a thin silicon wafer. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Directional selectivity and light-trapping in solar cells

The Yablonovitch limit for light trapping in solar cells with Lambertian surfaces can be increased using angle selective absorbers thereby exploiting the limited incidence angle of solar radiation. We simulate the efficiency gain or loss caused by an angular and energy selective filter on top of the absorber, compared to a Lambertian and a flat absorber. Additionally, we introduce two possible implementations of such a filter, a Rugate stack and inverted opal layers

Micromorph silicon tandem solar cells with fully integrated 3D photonic crystal intermediate reflectors

A 3D photonic intermediate reflector for textured micromorph silicon tandem solar cells has been investigated. In thin-film silicon tandem solar cells consisting of amorphous and microcrystalline silicon with two junctions of a-Si/c-Si, efficiency enhancements can be achieved by increasing the current density in the a-Si top cell providing an optimized current matching at high current densities. For an ideal photon-management between top and bottom cell, a spectrally-selective intermediate reflective layer (IRL) is necessary. We present the first fully-integrated 3D photonic thin-film IRL device incorporated on a planar substrate. Using a ZnO inverted opal structure the external quantum efficiency of the top cell in the spectral region of interest could be enhanced. As an outlook we present the design and the preparation of a 3D self organized photonic crystal structure in a textured micromorph tandem solar cell

3D photonic crystals for photon management in solar cells

Light management in single and tandem solar cells is becoming increasingly important to optimize the optical and electro-optical properties of solar cells. After a short introduction to state-of-the-art light management approaches, different applications of photonic crystals for photon management in solar cells are reviewed and discussed concerning their applicability. Results on direction- and energy-selective filters for ultra-lighttrapping, intermediate reflectors for optimal current matching in tandem cells, and photonic crystal coating for fluorescence collectors will be presented and discussed

Three-Dimensional Photonic Crystal Intermediate Reflectors for Enhanced Light-Trapping in Tandem Solar Cells

A three-dimensional photonic crystal intermediate reflector for enhanced light trapping in tandem solar cells is presented. The intermediate reflector consists of a transparent and conductive ZnO:Al inverted opal sandwiched in between the top amorphous silicon and bottom microcrystalline silicon cell