Angular behavior of the absorption limit in thin film silicon solar cells

We investigate the angular behavior of the upper bound of absorption provided by the guided modes in thin film solar cells. We show that the 4n2 limit can be potentially exceeded in a wide angular and wavelength range using two‐dimensional periodic thin film structures. Two models are used to estimate the absorption enhancement; in the first one, we apply the periodicity condition along the thickness of the thin film structure, but in the second one, we consider imperfect confinement of the wave to the device. To extract the guided modes, we use an automatized procedure that is established in this work. Through examples, we show that from the optical point of view, thin film structures have a high potential to be improved by changing their shape. Also, we discuss the nature of different optical resonances that can be potentially used to enhance light trapping in the solar cell. We investigate the two different polarization directions for one‐dimensional gratings, and we show that the transverse magnetic polarization can provide higher values of absorption enhancement. We also propose a way to reduce the angular dependence of the solar cell efficiency by the appropriate choice of periodic pattern. Finally, to obtain more practical values for the absorption enhancement, we consider the effect of parasitic loss that can significantly reduce the enhancement factor. Copyright © 2013 John Wiley & Sons, Ltd.

[1]  H. Herzig,et al.  Light trapping in solar cells at the extreme coupling limit , 2012, 1210.8276.

[2]  Ali Naqavi,et al.  Resonances and absorption enhancement in thin film silicon solar cells with periodic interface texture , 2011 .

[3]  H. Herzig,et al.  Understanding of photocurrent enhancement in real thin film solar cells: towards optimal one-dimensional gratings. , 2011, Optics express.

[4]  C. Ballif,et al.  Excitation of guided-mode resonances in thin film silicon solar cells , 2011 .

[5]  Gang Chen,et al.  Toward the Lambertian limit of light trapping in thin nanostructured silicon solar cells. , 2010, Nano letters.

[6]  F. Lederer,et al.  Comparison and optimization of randomly textured surfaces in thin-film solar cells. , 2010, Optics express.

[7]  S. Fan,et al.  Fundamental limit of light trapping in grating structures. , 2010, Optics express.

[8]  G. Whitesides,et al.  Light Trapping in Ultrathin Plasmonic Solar Cells References and Links , 2022 .

[9]  Christophe Ballif,et al.  Photocurrent increase in n-i-p thin film silicon solar cells by guided mode excitation via grating coupler , 2010 .

[10]  M. Zeman,et al.  Optimal design of periodic surface texture for thin‐film a‐Si:H solar cells , 2010 .

[11]  Zongfu Yu,et al.  Fundamental limit of nanophotonic light trapping in solar cells , 2010, Proceedings of the National Academy of Sciences.

[12]  H. Atwater,et al.  Plasmonics for improved photovoltaic devices. , 2010, Nature materials.

[13]  C. Ballif,et al.  Influence of the ZnO buffer on the guided mode structure in Si/ZnO/Ag multilayers , 2009 .

[14]  Christophe Ballif,et al.  TCOs for nip thin film silicon solar cells , 2009 .

[15]  D. A. Clugston,et al.  Crystalline silicon on glass (CSG) thin-film solar cell modules , 2004 .

[16]  Diego Fischer,et al.  Microcrystalline silicon and micromorph tandem solar cells , 1999 .

[17]  Thomas K. Gaylord,et al.  Determination of guided and leaky modes in lossless and lossy planar multilayer optical waveguides: reflection pole method and wavevector density method , 1999 .

[18]  D. Hall,et al.  Thermodynamic limit to light trapping in thin planar structures , 1997 .

[19]  J. R. Cozens,et al.  Optical Guided Waves and Devices , 1992 .

[20]  M. Green,et al.  Light trapping properties of pyramidally textured surfaces , 1987 .

[21]  Ping Sheng,et al.  Wavelength-selective absorption enhancement in thin-film solar cells , 1983 .

[22]  Y. Hayashi,et al.  Efficiency of the a-Si:H solar cell and grain size of SnO2transparent conductive film , 1983, IEEE Electron Device Letters.

[23]  G. Cody,et al.  Intensity enhancement in textured optical sheets for solar cells , 1982, IEEE Transactions on Electron Devices.

[24]  D. Carlson,et al.  AMORPHOUS SILICON SOLAR CELL , 1976 .