Testing and characterization of anti-reflection coatings on glass Diagnostic approaches at CSP M.Turek, M. Dyrba, S. Großer, V. Naumann, Ch. Hagendorf contact: marko.turek@csp.fraunhofer.de
Tests and methods 1. Modules and test-structures preparation of modules and minimodules with ARCglass and reference performance measurements stress tests, e.g. damp heat 2. Optics optical characterization of solar module constituents (ARCglass, polymers and solar cell) optical simulation of multi-layer systems 3. Microstructure, element analysis Structure and composition of ARC on large and small scale Advanced analysis of changes in structure, composition and residues in/on ARC Reliability root cause analysis 2
Tests and methods: System and test structure 1. Modules and test-structures preparation of modules and minimodules with ARCglass and reference performance measurements stress tests, e.g. damp heat Reliability minimodule power msmt stress test power msmt loss analysis 3
Tests and methods: Optics 2. Optics characterization of optical properties calculation of physical properties (dispersion relation, ) optical simulation of multi-layer systems optical properties of layer and interfaces in a solar module with ARC-glass surface 4
Tests and methods: Microstructure and element analysis Structure Analysis High resolution defect structure analysis and classification Correlative structure analysis using light and electron microscopy Optimized chemical analysis strategy (method + position) Element analysis of distinct structures and layers Detailed analysis of compositions Correlation of local structure and composition 3. Microstructure, element analysis Structure and composition of ARC on large and small scale Advanced analysis of changes in structure, composition and residues in/on ARC Defect mechanism Development of a root cause model to describe the aging mechanisms for understanding for avoidance strategy Root cause analysis 5
CSP Project Aging mechanism of ARC on glass LM: Dark field LM: Bright field SEM 6 Defect characterization and classification by correlated light microscopy (LM) and scanning electron microscopy (SEM) at the same sample position Project objective: Aging mechanism Root cause analysis Approach and methods: Detailed local microscopy study on surfaces and cross sections of coated glass samples (Light microscopy, SEM, EDX, XPS, ToF-SIMS) Optics + Structure + Composition Root cause SEM Defect detail: Hole within the surface at a magnification of x200.000
CSP Project Aging mechanism of ARC on glass Results: Several different degradation structures found Stains, flakes and scratches Site specific residues on the surface found and extrinsic elements identified The stain s rim shows an increased content of K, Ca, Cl, Mg, Al and Fe LM: Dark field SEM Measurement position SEM view on a breaking edge of a stressed ARC on glass (sample tilted) Local EDX element spectrum (red) exactly at the rim of the visible structure (glass reference spectrum is drawn as black line) 7