Research and developments in thin-film silicon photovoltaics

The increasing demand for photovoltaic devices and the associated crystalline silicon feedstock demand scenario have led in the past years to the fast growth of the thin film silicon industry. The high potential for cost reduction and the suitability for building integration have initiated both industrial and research laboratories dynamisms for amorphous silicon and micro-crystalline silicon based photovoltaic technologies. The recent progress towards higher efficiencies thin film silicon solar cells obtained at the IMT-EPFL in Neuchatel in small-area laboratory and semi-large-area industrial Plasma Enhanced Chemical Vapor Deposition (PE-CVD) systems are reviewed. Advanced light trapping schemes are fundamental to reach high conversion efficiency and the potential of advanced Transparent Conductive Oxides (TCO) is presented, together with issues associated to the impact of the substrate morphology onto the growth of the silicon films. The recent improvements realized in amorphous-microcrystalline tandem solar cells on glass substrate are then presented, and the latest results on 1 cm2 cells are reported with up to 13.3 % initial efficiency for small-area reactors and up to 12.3 % initial for large-area industrial reactors. Finally, the different strategies to reach an improved light confinement in a thin film solar cell deposited on a flexible substrate are discussed, with the incorporation of asymmetric intermediate reflectors. Results of micromorph solar cells in the n-i-p configuration with up to 9.8 % stabilized efficiency are reported.

[1]  J. Henz,et al.  Latest R&D Developments of Thin Film Silicon PV at Oerlikon Solar , 2008 .

[2]  M. Zeman,et al.  Optical modeling of a-Si:H solar cells with rough interfaces: Effect of back contact and interface roughness , 2000 .

[3]  Arvind Shah,et al.  Low pressure chemical vapour deposition of ZnO layers for thin-film solar cells: temperature-induced morphological changes , 2005 .

[4]  Reinhard Carius,et al.  Microcrystalline silicon solar cells deposited at high rates , 2005 .

[5]  Christophe Ballif,et al.  Opto-electronic properties of rough LP-CVD ZnO:B for use as TCO in thin-film silicon solar cells , 2007 .

[6]  P. Buehlmann,et al.  In situ silicon oxide based intermediate reflector for thin-film silicon micromorph solar cells , 2007 .

[7]  O. Kluth,et al.  Light Scattering in Microcrystalline Silicon Thin Film Solar Cells , 2000 .

[8]  P. Jarron,et al.  Hydrogenated Amorphous Silicon Sensor Deposited on Integrated Circuit for Radiation Detection , 2008, IEEE Transactions on Nuclear Science.

[9]  Arvind Shah,et al.  Relation between substrate surface morphology and microcrystalline silicon solar cell performance , 2008 .

[10]  T. Moriarty,et al.  High-efficiency amorphous and "micromorph" silicon solar cells , 2003, 3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of.

[11]  T. Moriarty,et al.  Potential of amorphous and microcrystalline silicon solar cells , 2004 .

[12]  Michio Kondo,et al.  Effects of Substrate Surface Morphology on Microcrystalline Silicon Solar Cells , 2001 .

[13]  A. Shah,et al.  High-Efficiency P-I-N Microcrystalline and Micromorph Thin Film Silicon Solar Cells Deposited on LPCVD Zno Coated Glass Substrates , 2006, 2006 IEEE 4th World Conference on Photovoltaic Energy Conference.

[14]  C. Ballif,et al.  Development of micromorph tandem solar cells on flexible low cost plastic substrates , 2009 .

[15]  Christophe Ballif,et al.  Optical management in high‐efficiency thin‐film silicon micromorph solar cells with a silicon oxide based intermediate reflector , 2008 .

[16]  J. Springer,et al.  TCO and light trapping in silicon thin film solar cells , 2004 .

[17]  S. Guha,et al.  Study of back reflectors for amorphous silicon alloy solar cell application , 1991 .

[18]  Kenji Yamamoto,et al.  High efficiency thin film silicon hybrid solar cell module on 1 m/sup 2/-class large area substrate , 2003, 3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of.

[19]  D. Staebler,et al.  Reversible conductivity changes in discharge‐produced amorphous Si , 1977 .

[20]  Kenji Yamamoto,et al.  A high efficiency thin film silicon solar cell and module , 2004 .

[21]  R. Schropp,et al.  Amorphous and ‘micromorph’ silicon tandem cells with high open-circuit voltage , 2005 .

[22]  Ch. Hof,et al.  On the Way towards High-Efficiency Thin Film Silicon Solar Cells by the "Micromorph" Concept , 1996 .

[23]  Eli Yablonovitch,et al.  Optically enhanced amorphous silicon solar cells , 1983 .

[24]  Ch. Hof,et al.  The "micromorph" solar cell: extending a-Si:H technology towards thin film crystalline silicon , 1996, Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996.

[25]  R. Schropp,et al.  Structural defects caused by a rough substrate and their influence on the performance of hydrogenated nano-crystalline silicon n-i-p solar cells , 2009 .

[26]  C. K. Carniglia,et al.  Scalar Scattering Theory for Multilayer Optical Coatings , 1979 .

[27]  H. Curtins,et al.  Influence of plasma excitation frequency fora-Si:H thin film deposition , 1987 .

[28]  V. Terrazzoni-Daudrix,et al.  Optimization of amorphous silicon thin film solar cells for flexible photovoltaics , 2008 .

[29]  Single and multi-junction thin film silicon solar cells for flexible photovoltaics , 2009 .