Print Email Facebook Twitter Thickness evaluation of AlOx barrier layers for encapsulation of flexible PV modules in industrial environments by normal reflectance and machine learning Title Thickness evaluation of AlOx barrier layers for encapsulation of flexible PV modules in industrial environments by normal reflectance and machine learning Author Grau-Luque, E. Guc, M. Becerril-Romero, I. Izqueierdo-Roca, V. Perez-Rodriguez, A. Bolt, P. van den Bruele, F.J. Ruhle, U. Publication year 2021 Abstract Flexible photovoltaic (PV) devices, such as those based on Cu (In,Ga)Se2 (CIGS) and perovskites, use polymeric front sheets for encapsulation that do not provide sufficient protection against the environment. The addition of nanometric AlxO layers by spatial atomic layer deposition (S-ALD) to these polymeric materials can highly improve environmental protection due to their low water vapor transmission rate and is a suitable solution to be applied in roll-to-roll industrial production lines. A precise control of the thickness of the AlOx layers is crucial to ensure an effective water barrier performance. However, current thickness evaluation methods of such nanometric layers are costly and complex to incorporate in industrial environments. In this context, the present work describes and demonstrates a novel characterization methodology based on normal reflectance measurements and either on control parameter-based calibration curves or machine learning algorithms that enable a precise, low-cost, and scalable assessment of the thickness of AlOx nanometric layers. In particular, the proposed methodology is applied for precisely determining the thickness AlOx nanolayers deposited on three different substrates relevant for the PV industry: monocrystalline Si, Cu (In,Ga)Se2 multistack flexible modules, and polyethylene terephthalate (PET) flexible encapsulation foil. The proposed methodology demonstrates a sensitivity Subject AlOxCIGSEncapsulationFlexible PVMachine learningNormal reflectanceProcess monitoringThickness assessmentIndustrial Innovation To reference this document use: http://resolver.tudelft.nl/uuid:ca3f61f9-b640-4e32-9ab4-2551e48f9174 DOI https://doi.org/10.1002/pip.3478 TNO identifier 960763 Source Progress in Photovoltaics Document type article Files To receive the publication files, please send an e-mail request to TNO Library.