This thesis deals with non-destructive testing (NDT). It Describes two basic thermographic methods, lock-in and pulse thermography. Different types of measurements using Fluke Ti55, points to the possibility of applying these methods in practice. Pulse thermography issue is a substantial part of this work, due to its good applicability. Also, it compares visual testing methods (VIS) and pulse thermography due to measurement with die-casting alloy AC-AlSi9Cu3 (Fe).

This diploma thesis is focused on using infrared camera within methods of active thermography. The first part of work is an introduction to the passive and active thermography; and about four basic methods of active thermography: step heating themography, Lock-in thermography and pulse phase thermography. The second part is a proposal of experimental working place. There are also presented results of practical implementation pulse and pulse phase methods tested for application of detection of subsurface defect.

L'objectif de la thèse fut d'étudier plusieurs techniques d'analyse de défaillance (Microscopie magnétique, Thermographie à détection synchrone, Tomographie à Rayons X, Réflectométrie Temporelle) sur leur propriété de localisation de défaut électrique (Court-circuit, circuit ouvert, ouvert résistif, etc.) sur des systèmes et composants électroniques 3D. Des possibilités d'évolution de ces techniques sont suggérées afin de permettre d'assurer la localisation des défauts dans ces nouveaux composants électroniques. Ceci passe notamment par la mise en place d'analyses magnétiques sur des échantillons inclinés ainsi que par l'introduction d'une imagerie de phase, et d'amplitude magnétique. Ce travail a également permis de proposer le couplage d'informations obtenues par microscopie magnétique et tomographique à rayons X dont l'ensemble serait piloté par simulation magnétique 3D. / The thesis purpose was to explore several failure analysis techniques (Magnetic microscopy, Lock-in Thermography, X-rays Tomography, Time Domain Reflectometry) on their capabilities to localize the electrical defect (Short circuit, open circuit, resistive open, etc.) on 3D electronic component and system. Assessment possibilities of these techniques are suggested in order to ensure the defect localization in these new components. In particular, implementations of magnetic analysis in tilted sample as well as introduction of phase and amplitude magnetic images have been realized. This work also proposes to couple information obtain from magnetic microscopy to X-rays Tomography where the all system would be driven by 3D magnetic simulation

<div>The manufacturing cost of solar cells along with their efficiency and reliability define the levelized cost of electricity (LCOE). One needs to reduce LCOE to make solar cells cost competitive compared to other sources of electricity. After a sustained decrease since 2001 the manufacturing cost of the dominant photovoltaic technology based on c-Si solar cells has recently reached a plateau. Further reduction in LCOE is only possible by increasing the efficiency and/or reliability of c-Si cells. Among alternate technologies, organic photovoltaics (OPV) has reduced manufacturing cost, but they do not offer any LCOE gain because their lifetime and efficiency are significantly lower than c-Si. Recently, perovskite solar cells have showed promising results in terms of both cost and efficiency, but their reliability/stability is still a concern and the physical origin of the efficiency gain is not fully understood.</div><div><br></div>In this work, we have collaborated with scientists industry and academia to explain the origin of the increased cell efficiency of bulk solution-processed perovskite cells. We also explored the possibility of enhancing the efficiency of the c-Si and perovskite cells by using them in a tandem configuration. To improve the intrinsic reliability, we have investigated 2D-perovskite cells with slightly lower efficiency but longer lifetime. We interpreted the behavior of the 2D-perovskite cells using randomly stacked quantum wells in the absorber region. We studied the reliability issues of c-Si modules and correlated series resistance of the modules directly to the solder bond failure. We also found out that finger thinning of the contacts at cell level manifests as a fake shunt resistance but is distinguishable from real shunt resistance by exploring the reverse bias or efficiency vs. irradiance. Then we proposed a physics-based model to predict the energy yield and lifetime of a module that suffers from solder bond failure using real field data by considering the statistical nature of the failure at module level. This model is part of a more comprehensive model that can predict the lifetime of a module that suffers from more degradation mechanisms such as yellowing, potential induced degradation, corrosion, soiling, delamination, etc. simultaneously. This method is called forward modeling since we start from environmental data and initial information of the module, and then predict the lifetime and time-dependent energy yield of a solar cell technology. As the future work, we will use our experience in forward modeling to deconvolve the reliability issues of a module that is fielded since each mechanism has a different electrical signature. Then by calibrating the forward model, we can predict the remaining lifetime of the fielded module. This work opens new pathways to achieve 2030 Sunshot goals of LCOE below 3c/kWh by predicting the lifetime that the product can be guaranteed, helping financial institutions regarding the risk of their investment, or national laboratories to redefine the qualification and reliability protocols.<br>