Solar energy industries are one of the fastest-growing industries in the global energy market. Between 2018 and 2019, installed capacity in Sweden increased by 70%. This is due to a combination of declining PV module and inverter costs, as well as  increased conversion to fossil-free energy production to mitigate greenhouse gas emissions. In fact, solar PVs have a 25-year life span, and soon many deployed PVs would soon reach their end of life (EoL), it is, therefore, important to organize for the EoL of PVs in order to recover precious resources and recycle PV modules in a sustainable manner. Currently, less than 10% of global solar cell waste is recycled, due to the lack of incentives for recycling in most countries. In the European Union, used-up modules are governed by the WEEE (Waste Electrical and Electronic Equipment) Directive, which requires the collection of 85% of solar cell waste, with at least 80% of the waste being prepared for reuse or recycling. Solar cell waste has not amounted to significant volumes in Sweden, due to the lack of no known systems for recycling. Used-up modules are currently collected and managed as electronic waste in one of two approved collection systems in Sweden. The aim of this thesis is to analyze and assess methods of recycling waste solar panels in Sweden and is it economically viable to set up a solar waste recycling center before it reaches the right amount of waste. Moreover, the main focus is on the analysis and comparison of the environmental impacts of various recycling methods for crystalline silicon (c-Si) and cadmium telluride (CdTe) panels. To recycle solar panel waste, the elements of these panels must be assessed from both an economic point of view as well as environmental impacts. Today, the most common PV panels in the global market and also Sweden are c-Si and CdTe types. The results showed except for the pyrolysis method, the environmental impacts of both c-Si and CdTe PV panels from the thermal-based recycling methods, are lower than chemical methods. Furthermore, the extraction of Al, Si, and glass from c-Si and the extraction of glass from CdTe has a less environmental impact than the current techniques used in the recycling of PV panels. Finally, in this study, we revealed which materials can be prioritized for maximum economic and environmental advantages from recycling. In c-Si modules, these are Ag, Al, Si, and glass and in CdTe modules, these are Te, Cu, and glass. Currently, investing in a new solar module recycling center in Sweden is not economically viable. Because the possibility of such an investment requires economic and political incentives. Given that by 2042 the volume of Swedish solar waste will not reach the minimum level of profitability to build a new specialized center for the recycling of solar modules, the best decision is to modify the existing plants in Sweden to recover expensive and vital materials.

Title: Point defects in materials for detection of X-ray and gamma radiation Author: Martin Rejhon Department: Institute of Physics of Charles University Supervisor: prof. Ing. Jan Franc, DrSc., Institute of Physics of Charles Uni- versity Abstract: Cadmium telluride and its compounds are suitable materials for pro- duction of X-ray and gamma-ray detectors working at room temperature. How- ever, the detector quality is affected by material imperfections, such as crystal defects and impurities. It results into forming of deep levels which act as re- combination and trapping centers. Then, the accumulated space charge at these deep levels influences electric and spectroscopic properties of the detector. In the end it may result in the polarization effect, when the electric field is localized in vicinity of one contact and detection properties are decreased. This thesis reports a complex study of a detector band structure by various meth- ods with focus on differences between CdTe, CdZnTe, CdTeSe and CdZnTeSe. The electro-optic Pockels effect is used to investigate the influence of the illumi- nation in range 900 − 1800 nm on the inner electric field. The temperature and time evolutions of the electric field after application of bias or switching of the additional light at 940 nm were measured to determine deep levels...

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Poptávka ze strany vesmírného výzkumu, zdravotnictví a bezpečnostního průmyslu způsobila v posledních letech zvýšený zájem o vývoj materiálů pro detekci a zobrazování vysokoenergetického záření. CdTe a jeho slitina CdZnTe. jsou polovodiče umožnují detekci záření o energiích v rozsahu 10 keV až 500 keV. Šířka zakázaného pásma u CdTe / CdZnTe je 1.46 -1.6 eV, což umožňuje produkci krystalů o vysoké rezistivitě (10^10-10^11 cm), která je dostačující pro použití CdTe / CdZnTe při pokojové teplotě. V mé práci byly zkoumány detektory CdTe/CdZnTe v různých stádiích jejich poruchovosti. Byly použity velmi kvalitní spektroskopické detektory, materiál s nižší rezistivitou a výraznou polarizací, detektory s asymetrií elektrických parametrů kontaktů a teplotně degenerované vzorky. Z výsledků analýzy nízkofrekvenčního šumu je patrný obecný závěr, že zvýšená koncentrace defektů způsobí změnu povahy původně monotónního spektra typu 1/f na spektrum s výrazným vlivem generačně-rekombinačních procesů. Další výrazná vlastnost degenerovaných detektorů a detektorů nižší kvality je nárůst spektrální hustoty šumu typu 1/f se vzrůstajícím napájecím napětí se směrnicí výrazně vyšší než 2. Strukturální a chemické analýzy poukázaly, že teplotní generace detektorů způsobuje difuzi kovu použitého při kontaktování a stopových prvků hlouběji do objemu krystalu. Část mé práce je věnována modifikaci povrchu svazkem argonových iontů a jejímu vlivu na chemické složení a morfologii povrchu.

Thin-film solar cell research is central to the electricity production of the near future. Photovoltaic technologies based on silicon have a significant portion of the global market and installed capacity. Thin-film solar cells are port of the emerging photovoltaic technologies that are challenging silicon for a part of the electricity production based on solar power. These thin-film technologies, such as copper indium gallium selenide (CIGS) and cadmium telluride (CdTe), are lower cost and require less energy to produce, but also require rare materials. An alternative to these technologies are thin-film solar cells based on more abundant materials. To develop these new materials at Uppsala University, combinatorial synthesis is used. This method produces a significant amount of data across different measurement methods. The data needs to be analysed and combined to gather information about the characteristics of the materials being developed. To facilitate the analysis and combination of data, a database tool was created in MATLAB. The result is a program that allows its User to combine energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy and Photoluminescence spectroscopy measurements done on solar cell absorber layers. Absorber layers are the section of solar cells where sun lighet is absorbed, and electron-hole pairs are created. The program provides multiple figures and graphs combining the different data collected, enabling the User to draw conclusions about the characteristics of the sample and its suitability as an absorber layer. The combinatorial synthesis database tool created could be user for combinatorial synthesis analysis of other material samples that are not necessarily absorber layers for thin-film solar cells. This report describes both the development of the tool and the code itself.

Ce travail de Thèse est lié à l'émergence d'un nouvel axe scientifique de recherche : la science X ultrarapide. La recherche effectuée dans les communautés des lasers intenses et des accélérateurs (synchrotrons) met en évidence une nouvelle génération d'outils associés au rayonnement X, les sources X ultrabrèves. Ces nouvelles sources de durée d'impulsion d'une centaine de femtosecondes (1 fs = 10e-15 s) devraient avoir un impact formidable, par exemple, dans l'étude de la dynamique atomique qui est actuellement limitée à plusieurs dizaines de picosecondes (1 ps = 10e-12 s). Cette thèse présente la première expérience d'application de ces sources X ultrabrèves qui utilisent le rayonnement X produit par l'interaction d'un laser intense avec une cible solide (source laser/plasma). La transition de phase solide/liquide ultrarapide d'un semi conducteur a été mise en évidence et caractérisée à l'aide de la technique de diffraction X résolue en temps. L'analyse des résultats expérimentaux a été effectuée à l'aide d'un modèle simple de l'interaction laser semi conducteur reposant sur une extrapolation du modèle de Drude pour un régime à haute densité de porteurs (10e22 /cm3).