Modelling water vapour permeability through atomic layer deposition coated photovoltaic barrier defects

Abstract Transparent barrier films such as Al 2 O 3 used for prevention of oxygen and/or water vapour permeation are the subject of increasing research interest when used for the encapsulation of flexible photovoltaic modules. However, the existence of micro-scale defects in the barrier surface topography has been shown to have the potential to facilitate water vapour ingress, thereby reducing cell efficiency and causing internal electrical shorts. Previous work has shown that small defects (≤ 3 μm lateral dimension) were less significant in determining water vapour ingress. In contrast, larger defects (≥ 3 μm lateral dimension) seem to be more detrimental to the barrier functionality. Experimental results based on surface topography segmentation analysis and a model presented in this paper will be used to test the hypothesis that the major contributing defects to water vapour transmission rate are small numbers of large defects. The model highlighted in this study has the potential to be used for gaining a better understanding of photovoltaic module efficiency and performance.

[1]  S. Wroblewski.  Ueber die Natur der Absorption der Gase , 1879 .

[2]  William Henry,et al.  III. Experiments on the quantity of gases absorbed by water, at different temperatures, and under different pressures , 1803, Philosophical Transactions of the Royal Society of London.

[3]  David Julien Louis Brémaud.  Investigation and development of CIGS solar cells on flexible substrates and with alternative electrical back contacts , 2009 .

[4]  Liam Blunt,et al.  Further development of surface metrology methods for predicting the functional performance of flexible photovoltaic barrier films , 2013 .

[5]  R. J. Ashley,et al.  Permeability and Plastics Packaging , 1985 .

[6]  T. Tsuru,et al.  Chapter 6 - Gas Permeation Properties of Helium, Hydrogen, and Polar Molecules Through Microporous Silica Membranes at High Temperatures: Correlation with Silica Network Structure , 2011 .

[7]  S. George,et al.  Surface chemistry for molecular layer deposition of organic and hybrid organic-inorganic polymers. , 2009, Accounts of chemical research.

[8]  Mohamed Latreche,et al.  Transparent barrier coatings on polyethylene terephthalate by single- and dual-frequency plasma-enhanced chemical vapor deposition , 1998 .

[9]  Liam Blunt,et al.  Advanced Techniques for Assessment Surface Topography: Development of a Basis for 3D Surface Texture Standards "Surfstand" , 2003 .

[10]  Arrelaine A. Dameron,et al.  Gas Diffusion Barriers on Polymers Using Multilayers Fabricated by Al2O3 and Rapid SiO2 Atomic Layer Deposition , 2008 .

[11]  F. Debeaufort,et al.  Water vapor permeability and diffusivity through methylcellulose edible films , 1994 .

[12]  Su-Huai Wei,et al.  Effects of Ga addition to CuInSe2 on its electronic, structural, and defect properties , 1998 .

[13]  M. Kempe.  Control of moisture ingress into photovoltaic modules , 2005, Conference Record of the Thirty-first IEEE Photovoltaic Specialists Conference, 2005..

[14]  Hood Chatham,et al.  Oxygen diffusion barrier properties of transparent oxide coatings on polymeric substrates , 1996 .

[15]  R. McLean,et al.  ALD Moisture Barrier for Cu(InGa)Se2 Solar Cells , 2010 .

[16]  B. M. Henry,et al.  Characterisation of aluminium oxynitride gas barrier films , 2001 .

[17]  K. J. Stout,et al.  Three-Dimensional Surface Topography , 2000 .

[18]  Liam Blunt,et al.  Numerical Parameters for Characterisation of Topography , 2003 .

[19]  Liam Blunt,et al.  Paradigm shifts in surface metrology. Part II. The current shift , 2007, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[20]  B. M. Henry,et al.  Mechanism of Water Vapor Transport through PET/AlOxNy Gas Barrier Films , 2004 .

[21]  Steven M. George,et al.  Electroplating to visualize defects in Al2O3 thin films grown using atomic layer deposition , 2009 .

[22]  S. George.  Atomic layer deposition: an overview. , 2010, Chemical reviews.

[23]  J. M. Martínez-Duart,et al.  Atomic force microscopy (AFM) morphological surface characterization of transparent gas barrier coatings on plastic films , 1996 .

[24]  A. Urbaniak,et al.  Defect states in the GIGS solar cells by photocapacitance and deep level optical spectroscopy , 2005 .

[25]  M. Weaver,et al.  Thin-film permeation-barrier technology for flexible organic light-emitting devices , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[26]  B. Duncan,et al.  Review of measurement and modelling of permeation and diffusion in polymers. , 2005 .

[27]  Mohamed Latreche,et al.  Defect-permeation correlation for ultrathin transparent barrier coatings on polymers , 2000 .

[28]  W. Peukert,et al.  Inorganic Layers on Polymeric Films – Influence of Defects and Morphology on Barrier Properties , 2003 .

[29]  Perry D. Haaland,et al.  SiOx Gas Barrier Coatings on Polymer Substrates: Morphology and Gas Transport Considerations , 1999 .

[30]  C. Thanachayanont,et al.  PREPARATION OF CdIn2Se4n-TYPE SEMICONDUCTOR USED AS THERMOELECTRIC MATERIAL BY SOL–GEL METHOD , 2009 .

[31]  J. Hotchkiss,et al.  Food-packaging interactions influencing quality and safety. , 1997, Food Additives and Contaminants.

[32]  Liam Blunt,et al.  Correlation of micro and nano–scale defects with WVTR for aluminium oxide barrier coatings for flexible photovoltaic modules , 2013 .

[33]  S. George,et al.  H2O vapor transmission rate through polyethylene naphthalate polymer using the electrical Ca test. , 2013, The journal of physical chemistry. A.

[34]  Steven M. George,et al.  Fluorescent tags to visualize defects in Al2O3 thin films grown using atomic layer deposition , 2009 .

[35]  Steven S. Hegedus,et al.  (Invited) ALD Moisture Barrier for Cu(InGa)Se2 Solar Cells , 2010 .