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AML is a heterogeneous disease characterized by high rate of relapse and mortality. While chemotherapies may eradicate blasts, they are less effective in eliminating relapse-causing Leukemic Stem Cells (LSCs). Although LSCs are usually identified as CD34+CD38- cells, there is significant heterogeneity in surface marker expression and CD34- LSCs exist particularly in NPM1mut AMLs. By analyzing diagnostic primary DNMT3AmutNPM1mut AML samples, we suggest a novel flow cytometry sorting strategy particularly useful for CD34neg AML subtypes. To enrich for LSCs independently of CD34 status, positive selection for GPR56 and negative selection for NKG2D-Ligands are employed. We demonstrate that the functional reconstitution capacity of CD34- and CD34+ LSCs as well as their transcriptomes are very similar supporting phenotypic plasticity. Furthermore, we show that while CD34+ subpopulations can contain next to LSCs also normal and/or pre-leukemic Hematopoietic Stem Cells (HSCs), this is not the case in CD34-GPR56+NKG2DL- enriched LSCs which thus can be isolated with high purity. Finally, we show that AML patients, who retain at time of diagnosis a reserve of normal and/or preleukemic HSCs in their bone marrow able to reconstitute immunocompromised mice, have significant longer relapse-free and overall survival compared to AML patients in whom functional HSCs are no longer detectable.

8th World Conference on Photovoltaic Energy Conversion; 102-106, A novel approach for interdigitated back contacted (IBC) solar cell production featuring polycrystalline silicon on interfacial oxide (poly-Si/SiOx) passivating contacts on both polarities is introduced, namely the polyZEBRA concept, which is based on the IBC solar cell process ZEBRA. The process sequence is compatible with standard industrial equipment, i.e. IBC patterning via laser processing and metallization for both polarities in one single screenprinting step. This approach allows for an upgrade of existing ZEBRA production lines with minimal additional costs. The champion polyZEBRA cell produced so far reached an in-house efficiency of 23.5% on full area wafer size. Besides the introduction of the polyZEBRA concept, an optimization of the gap/front side BBr3-diffusion towards low recombination is presented, enabling 6 mV higher open-circuit voltage on cell level compared to the baseline.

8th World Conference on Photovoltaic Energy Conversion; 22-28, The present study investigates the passivation of layer stacks consisting of an interfacial oxide, LPCVD deposited polycrystalline silicon (poly-Si) and PECVD deposited silicon nitride (SiNx) layers when subjecting them to high temperature processes after the deposition of SiNx. We show that the passivation of such poly-Si/SiNx layer stacks can be severely degraded by high temperature processes. Further, we found that the passivation can be recovered after removing the annealed SiNx layer and subsequent annealing of the c-Si/SiO2/poly-Si interface. We conclude that thermal stress, induced by the densification of SiNx contributes to the loss of passivation at the c-Si/SiO2/poly-Si interface. Comparing symmetric and asymmetric sample structures, where the poly-Si/SiNx stack is present on both and on only one side respectively, shows that stress induced de-passivation and the re-passivation of poly-Si/SiNx stacks cannot be appropriately studied with symmetric test structures under certain circumstances. The importance of these findings is underlined when developing cell concepts that require the presence of such stacks in high temperature process steps. As an example, results for TOPCon cell precursors fabricated with an alternative process sequence with poly-Si deposition before BBr3 emitter diffusion are presented. Although the poly-Si layer was capped with SiNx during the emitter diffusion, cell precursors with iVoc values of up to 709 mV could be produced with this process. We further propose to consider stress-induced de-passivation as potential root-cause for the degradation of the passivation of polySi/SiNx stacks during the firing process of such samples.

8th World Conference on Photovoltaic Energy Conversion; 1099-1104, In this work we give an overview of the module monitoring results achieved within the H2020 funded project called HighLite. A dedicated online monitoring platform has been developed for the project to group and treat the data from all partners with homogeneous procedures. Monitoring of advanced prototype modules developed in the project and based on various cells and interconnection approaches, like silicon-heterojunction (SHJ)-shingle, TopCon-shingle, cut interdigital back-contact cells (cut-IBC) are reported. We describe key learnings from monitoring modules for various applications including building-applied PV (BAPV) and building-integrated PV (BIPV). Annual energy yield up to 1900 kWh/kWp is expected in Cadarache (France) based on HighLite PV technology. Temperature corrected performance ratios are used for a ranking of the new technologies against the reference PERC modules.

38th European Photovoltaic Solar Energy Conference and Exhibition; 229-232, Interpreting results of spatially resolved characterization methods can prove quite a challenge and it may often happen that a phenomenon takes credit for something it is not responsible for. This is especially important when imaging laterally inhomogeneous devices. We present a derivation, application and validation of a combined opto-electrical model, which sheds light on the roles electrical and optical effects play when it comes to interpretation of EL measurements. We show not only that the device optics and imaging optics cannot be neglected but that they in fact play a major role in shaping the EL measurements.

38th European Photovoltaic Solar Energy Conference and Exhibition; 533-537, The EU crystalline silicon (c-Si) PV manufacturing industry has faced strong foreign competition in the last decade. To strive in this competitive environment, the EU c-Si PV manufacturing industry needs to focus on highly performing c-Si PV technologies and on reducing environmental impact (lower CO2 footprint, improved sustainability, recyclability, etc.). In this work, we give an overview of the latest results achieved within the H2020 funded project called HighLite which addresses the work programme LC-SC3-RES-15-2019: Increase the competitiveness of the EU PV manufacturing industry. We report the progress made when implementing novel layers and processes in existing pilot-lines producing high-efficiency n-type silicon heterojunction (SHJ) cells with a shingle layout and interdigitated back-contact (IBC) cells with passivated contacts. In particular, we present the work done together with several industrial partners towards innovative production equipment for assembly of cut-cells into PV modules. Finally, we explain key learnings made so far when tailoring c-Si PV modules for various applications including building-applied PV (BAPV), building-integrated PV (BIPV) and vehicle-integrated PV (VIPV).

Recent experimental progress in the field of cavity quantum electrodynamics allows to study the regime of strong interaction between quantized light and complex matter systems. Due to the coherent coupling between photons and matter-degrees of freedom, polaritons - hybrid light-matter quasiparticles - emerge, which can significantly influence matter properties and complex process such as chemical reactions. This strong-coupling regime opens up possibilities to control materials and chemistry in an unprecedented way. However, the precise mechanisms behind many of these phenomena are not yet entirely understood. One important reason is that often the physical problem is described with highly simplified models, where the matter system is reduced to a few effective levels. More accurate first-principles approaches that consider photons on the same footing as electrons only slowly emerge. Their development is hampered by the increase of complexity of the combined electron-photon wave functions and the fact that we have to deal with two different species of particles. In this thesis we propose a way to overcome these problems by reformulating the coupled electron-photon problem in an exact way in a different, purpose-build Hilbert space, where no longer electrons and photons are the basic physical entities but the polaritons. Representing an N-electron-M-mode system by an N-polariton wave function with hybrid Fermi-Bose statistics, we show explicitly how to turn electronic-structure methods into polaritonic-structure methods that are accurate from the weak to the strong-coupling regime. We elucidate this paradigmatic shift by a comprehensive review of light-matter coupling, as well as by highlighting the connection between different electronic-structure methods and quantum-optical models. This extensive discussion accentuates that the polariton description is not only a mathematical trick, but it is grounded in a simple and intuitive physical argument: when the excitations of a system are hybrid entities a formulation of the theory in terms of these new entities is natural. Finally, we discuss in great detail how to adopt standard algorithms of electronic-structure methods to adhere to the new hybrid Fermi-Bose statistics. Guaranteeing the corresponding nonlinear inequality constraints in practice requires a careful development, implementation and validation of numerical algorithms. This extra numerical complexity is the price we pay for making the coupled matter-photon problem feasible for first-principle methods. Neueste experimentelle Fortschritte im Bereich von ``Cavity''-Quantenelektrodynamik ermöglichen die Erforschung der starken Wechselwirkung zwischen quantisiertem Licht und komplexen Materiesystemen. Aufgrund der kohärenten Kopplung zwischen Photonen und Materiefreiheitsgraden, entstehen Polaritonen, hybride Licht-Materie Quasiteilchen, die dazu beitragen können, Materieeigenschaften und komplexe Prozesse wie chemische Reaktionen entscheidend zu beeinflussen. Dieses Regime der starken Kopplung eröffnet Möglichkeiten zur Kontrolle von Materialien und Chemie in einer beispiellosen weise. Allerdings sind die genauen Mechanismen hinter vielen solcher Phänomene nicht vollständig verstanden. Ein wichtiger Grund dafür ist, dass das physikalische Problem oft mit äußerst vereinfachten Methoden beschrieben wird, wobei die Materie zu wenigen effektiven "Levels" reduziert wird. Akkuratere first-principles Methoden, die Photonen gleichwertig zu Elektronen behandeln entstehen nur langsam, da die Erforschung solcher Methoden sowohl durch die erhöhte Komplexität der kombinierten Elektron-Photon Wellenfunktionen, als auch dem Fakt, dass zwei verschiedene Teilchenspezies miteinbezogen werden müssen, aufgehalten wird. In dieser Doktorarbeit schlagen wir vor diese Problem zu umgehen, indem das gekoppelte Elektron-Photon Problem exakt in einem anderen zweckgebauten Hilbertraum neuformuliert wird. Dadurch, dass wir ein System, bestehend aus N Elektronen und M Moden, mit einer N-Polaritonen Wellenfunktion repräsentieren, können wir explizit zeigen wie ein electronic-structure in eine polaritonic-structure Methode umgewandelt werden kann, die für schwache bis hin zu starken Kopplungstärken akkurat ist. Wir rationalisieren diesen Paradigmenwechsel innerhalb einer umfassenden Revision der Licht-Materie Wechselwirkung und indem wir die Verbindung zwischen verschiedenen electronic-structure Methoden und quantenoptischen Modellen hervorheben. Diese ausführliche Diskussion hebt hervor, dass die Polariton-Konstruktion nicht nur ein mathematischer Trick ist, sondern auf einem einfachen und physikalischem Argument basiert: wenn die Anregungen eines Systems einen hybriden Charakter haben, dann ist es nur natürlich, die zugehörige Theorie bezüglich dieser neuen Entitäten zu formulieren. Schließlich diskutieren wir ausführlich, wie Standard-Algorithmen von electronic-structure Methoden angepasst werden müssen, um der neuen Fermi-Bose Statistik gerecht zu werden. Um die zugehörigen nichtlinearen Ungleichungs-Nebenbedingungen zu garantieren, sind sorgfältige Entwicklung, Implementierung und Validierung der numerischen Algorithmen nötig. Diese zusätzliche numerische Komplexität ist der Preis, den wir zahlen, um das gekoppelte Elektron-Photon Problem zugänglich zu first-principles Methoden zu machen.

38th European Photovoltaic Solar Energy Conference and Exhibition; 181-185, The aim of this work is to demonstrate the maturity of the TOPCon technology by conducting a round-robin on symmetrically processed lifetime samples in the leading European PV institutes EPFL, ISC, CEA-INES, ISFH, IMEC and Fraunhofer ISE within the H2020 funded project called HighLite. For all layers, dark saturation current-densities ranging between 2-10 fA/cm² can be reported. Simultaneously, no metal induced recombination for the two lower sintering temperatures have been observed pointing towards a true passivated contact. Furthermore, contact resistivities below 10 mcm² have been achieved. It seems that the industrial passivating contact matured to a fully passivated and conducting contact enabling full efficiency potential. The fact that this can be realized using either PECVD or LPCVD from various manufacturer is expected to drive costs down and contribute to the increased adoption of the TOPCon technology.

38th European Photovoltaic Solar Energy Conference and Exhibition; 253-256, Many new module designs feature cut cells, especially now that cell and module manufacturers are introducing larger wafer formats (166mm, 182mm, and even 210mm in edge length). However, the cutting procedure introduces extra power losses. This recombination occurs when the cut edge is damaged by a high power laser or exposed to the air without passivation. In this paper, we employ high resolution photoluminescence to investigate the effect of edge recombination on interdigitated back contact solar cells. Edge recombination losses are compared by comparing various photoluminescence profiles obtained from the samples with different structures and cut techniques. First, we compare various laser cutting techniques at various locations. Two questions are addressed: where to cut the cells and how to cut them. Last, we compare the repassivation ability of the samples with different cutting techniques and structures. Repassivation can be used to mitigate edge cut losses with specific cutting techniques.

38th European Photovoltaic Solar Energy Conference and Exhibition; 140-143, A simple, mask-less process for the fabrication of localized p+ poly-Si structures is presented based on etch selectivity of highly doped p+ poly-Si. We show the optimization steps that were necessary to obtain a reliable, uniform and reproducible process, namely optimization of the doping source layer, laser parameters, alkaline etching and texturing step. Furthermore, the dopant profiles were tuned by different BBr3 emitter diffusions in combination with tunnel oxide thickness variation. The suggested process flow allows for simple integration in the our n-type passivated contact cell concept TOUCAN™ as selective poly-Si emitter layers below the metal fingers on the front side.

37th European Photovoltaic Solar Energy Conference and Exhibition; 308-311, The interconnection of cut cells is a way to improve cell to module efficiency ratio. While this approach minimizes series resistance losses and improves module area utilization, it introduces recombination losses due to imperfect cuts. We propose two additional methods to characterize edge recombination based on multi-wavelength light beam induced current (LBIC) measurements and current-dependent spatially resolved electroluminescence (EL). We test the methods on interdigitated back contact silicon solar cells, which were cut in our laboratory using a not yet optimized procedure with laser ablation and mechanical cleaving. The proposed LBIC based measurement offers an easy interpretation as its result can be directly linked to the local external quantum efficiency, while the proposed EL method can be used as an alternative to the established PL methods without the need of a light source. The results show a clear distinction between cut and uncut edges, which was observed with both methods. The influence of edge recombination is still evident 2 mm away from the cell edge in the EL measurements, and 1 mm and 0.5 mm in the LBIC measurements at 1060 and 642 nm, respectively. For the uncut edge the influence is smaller. Based on the LBIC measurements, the EQE loss at the cut edge is estimated to be 9% for a 1 mm and 0.5 mm wide area along the edge for 1060 and 642 nm, respectively. We also observed a non-intuitive EL behaviour, since the EL signal obtained with high current bias decreases faster towards the edge than the EL signal obtained with low bias current. Similarly, a difference between normalized LBIC profiles is observed at different wavelengths. For the uncut edge, the LBIC signal has a slightly steeper response at 1060 nm than at 642 nm.

This article compares the expression and applicability of biomarkers, from single genes and gene signatures, identified in patients with locally advanced head and neck squamous cell carcinoma using the GeneChip Human Transcriptome Array 2.0, nCounter, and real-time PCR analyses. Two multicenter, retrospective cohorts of patients with head and neck squamous cell carcinoma from the German Cancer Consortium Radiation Oncology Group who received postoperative radiochemotherapy or primary radiochemotherapy were considered. Real-time PCR was performed for a limited number of 38 genes of the cohort who received postoperative radiochemotherapy only. Correlations between the methods were evaluated by the Spearman rank correlation coefficient. Patients were stratified based on the expression of putative cancer stem cell markers, hypoxia-associated gene signatures, and a previously developed seven-gene signature. Locoregional tumor control was compared between these patient subgroups using log-rank tests. Gene expressions obtained from nCounter analyses were moderately correlated to GeneChip analyses (median rho = approximately 0.68). A higher correlation was obtained between nCounter analyses and real-time PCR (median rho = 0.84). Significant associations with locoregional tumor control were observed for most of the considered biomarkers evaluated by GeneChip and nCounter analyses. In general, all applied biomarkers (single genes and gene signatures) classified approximately 70% to 85% of the patients similarly. Overall, gene signatures seem to be more robust and had a better transferability among different measurement methods.

37th European Photovoltaic Solar Energy Conference and Exhibition; 322-328, Power losses in solar cells and modules due to recombination at cut cell edges is a problem of increasing concern since many new and future module concepts use cut cells, and particularly as the PV industry moves to larger wafer formats. Herein, we first demonstrate the use of high resolution photoluminescence imaging combined with quasi steady state photoconductance measurements to calculate carrier lifetime directly from photoluminescence images, and discuss the factors and limitations involved in this method. We then compare the edge recombination dynamics in interdigitated back contact solar cells and heterojunction solar cells as a function of the method used to cut them, and show several important differences. Finally, we explore some edge passivation strategies that could be used to mitigate the negative effects of cutting.