An efficient light trapping scheme based on textured conductive photonic crystal back reflector for performance improvement of amorphous silicon solar cells

2014 ◽  
Vol 105 (7) ◽  
pp. 073506 ◽  
Author(s):  
Peizhuan Chen ◽  
Guofu Hou ◽  
QiHua Fan ◽  
Qian Huang ◽  
Jing Zhao ◽  
...  
2008 ◽  
Vol 1101 ◽  
Author(s):  
Janez Krc ◽  
Andrej Campa ◽  
Stefan L. Luxembourg ◽  
Miro Zeman ◽  
Marko Topic

AbstractAdvanced light management in thin-film solar cells is important in order to improve the photo-current and, thus, to raise up the conversion efficiencies of the solar cells. In this article two types of periodic structures ¡V one-dimensional diffraction gratings and photonic crystals,are analyzed in the direction of showing their potential for improved light trapping in thin-film silicon solar cells. The anti-reflective effects and enhanced scattering at the gratings with the triangular and rectangular features are studied by means of two-dimensional optical simulations. Simulations of the complete microcrystalline solar cell incorporating the gratings at all interfaces are presented. Critical optical issues to be overcome for achieving the performances of the cells with the optimized randomly textured interfaces are pointed out. Reflectance measurements for the designed 12 layer photonic crystal stack consisting of amorphous silicon nitride and amorphous silicon layers are presented and compared with the simulations. High reflectance (up to 99 %) of the stack is measured for a broad wavelength spectrum. By means of optical simulations the potential for using a simple photonic crystal structure as a back reflector in an amorphous silicon solar cell is demonstrated.


2010 ◽  
Vol 1245 ◽  
Author(s):  
Benjamin Curtin ◽  
Rana Biswas ◽  
Vikram Dalal

AbstractPhotonic crystal back reflectors offer enhanced optical absorption in thin-film solar cells, without undesirable losses. Rigorous simulations of photonic crystal back reflectors predicted maximized light absorption in amorphous silicon solar cells for a pitch of 700-800 nm. Simulations also predict that for typical 250 nm i-layer cells, the periodic photonic crystal back reflector can improve absorption over the ideal randomly roughened back reflector (or the ‘4n2classical limit') at wavelengths near the band edge. The PC back reflector provides even higher enhancement than roughened back reflectors for cells with even thinner i-layers. Using these simulated designs, we fabricated metallic photonic crystal back reflectors with different etch depths and i-layer thicknesses. The photonic crystals had a pitch of 760 nm and triangular lattice symmetry. The average light absorption increased with the PC back reflectors, but the greatest improvement (7-8%) in short circuit current was found for thinner i-layers. We have studied the dependence of cell performance on the etch depth of the photonic crystal. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.


2006 ◽  
Vol 910 ◽  
Author(s):  
Janez Krc ◽  
M. Zeman ◽  
A. Campa ◽  
F. Smole ◽  
M. Topic

AbstractIn order to improve light trapping in thin-film silicon solar cells two novel approaches are investigated in this article: angle-selective management of light scattering inside the solar cell and wavelength-selective manipulation of high reflectance or transmittance of light. Diffraction gratings are analyzed as a representative of the first approach. Haze and angular distribution function of scattered (diffracted) light in reflection are measured for aluminum-based rectangular periodic gratings with different period and height of the rectangles. High haze values in specific wavelength region and scattering angles of the investigated gratings measured in air and water agree very well with the theoretical predictions. Considering the actual optical situation in microcrystalline silicon solar cells, optimal period and height of the rectangular gratings applied as a back reflector are calculated for obtaining the total reflection at the front interfaces. In the frame of the second approach, photonic-crystal-like structures are introduced. By means of optical simulations photonic-crystal-like structures are investigated for two possible applications: an intermediate reflector in a micromorph silicon solar cell with wavelength-selective reflectivity and a dielectric back reflector with a high reflectance in the long-wavelength region. The photonic crystal structure consisting of sequences of n-doped amorphous silicon and ZnO layers is designed for the efficient intermediate reflector. For the back reflector with a high reflectance the structures with intrinsic amorphous silicon, SiO2, MgF2 and TiO2 are proposed.


2010 ◽  
Vol 1248 ◽  
Author(s):  
Benjamin Curtin ◽  
Rana Biswas ◽  
Vikram Dalal

AbstractWe develop experimentally and theoretically plasmonic and photonic crystals for enhancing thin film silicon solar cells. Thin film amorphous silicon (a-Si:H) solar cells suffer from decreased absorption of red and near-infrared photons, where the photon absorption length is large. Simulations predict maximal light absorption for a pitch of 700-800 nm for photonic crystal hole arrays in silver or ZnO/Ag back reflectors, with absorption increases of ~12%. The photonic crystal improves over the ideal randomly roughened back reflector (or the ‘4n2limit’) at wavelengths near the band edge. We fabricated metallic photonic crystal back-reflectors using photolithography and reactive-ion etching. We conformally deposited a-Si:H solar cells on triangular lattice hole arrays of pitch 760 nm on silver back-reflectors. Electron microscopy demonstrates excellent long range periodicity and conformal a-Si:H growth. The measured quantum efficiency increases by 7-8 %, relative to a flat reflector reference device, with enhancement factors exceeding 6 at near-infrared wavelengths. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.


Solar Energy ◽  
2013 ◽  
Vol 97 ◽  
pp. 591-595 ◽  
Author(s):  
C. Banerjee ◽  
T. Srikanth ◽  
U. Basavaraju ◽  
R.M. Tomy ◽  
M.G. Sreenivasan ◽  
...  

2010 ◽  
Author(s):  
Carolin Ulbrich ◽  
Marius Peters ◽  
Muhammad Tayyib ◽  
Benedikt Blaesi ◽  
Thomas Kirchartz ◽  
...  

2013 ◽  
Vol 113 (6) ◽  
pp. 064508 ◽  
Author(s):  
V. Demontis ◽  
C. Sanna ◽  
J. Melskens ◽  
R. Santbergen ◽  
A. H. M. Smets ◽  
...  

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