0000000000023918
AUTHOR
Ralf B. Wehrspohn
showing 7 related works from this author
3D photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells
2012
The concept of 3D photonic crystals embedded in tandem solar cells as intermediate reflective layers is investigated. Numerical as well as experimental results will be presented.
Inverted-opal photonic crystals for ultra light-trapping in solar cells
2010
We investigated a three dimensional inverted opal having the potential to notably increase light-trapping in solar cells. The 3D photonic crystal top layer is an angle- and direction-selective filter, which decreases the acceptance cone of the solar cell. Numerical optimisation methods are used to verify the optical and electrical properties for a large angluar and energy spectrum for a system consisting of an inverted opal on top of a thin crystalline silicon solar cell. It is numerically shown that an inverted opal grown in the Τ - Xdirection might fulfill the requirement for such a filter. An estimate for the theoretically achievable efficiency for nonconcentrated light is presented that…
Transparent conductive oxide photonic crystals on textured substrates
2011
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.
Three-dimensional photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells
2011
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.
Photonic crystal intermediate reflector in micromorph tandem solar cells
2011
Experimental and numerical evidences are presented which show that the efficiency of silicon based tandem solar-cells can be increased by incorporating a three-dimensional photonic crystal as an intermediate reflector.
3D photonic crystal intermediate reflector for micromorph thin-film tandem solar cell
2008
The concept of 3D photonic intermediate reflectors for 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/μc-Si, efficiency enhancements can be achieved by increasing the current density in the a-Si top cell. It is one goal to provide 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, which is less dependent of the angle of incidence than state-of-the-art thickness dependent massive interlayers. The design, preparation and cha…
Micromorph silicon tandem solar cells with fully integrated 3D photonic crystal intermediate reflectors
2010
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 eff…