128 research outputs found

    Hybrid Perovskite Degradation from an Optical Perspective A Spectroscopic Ellipsometry Study from the Deep Ultraviolet to the Middle Infrared

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    A quantitative analysis of the thermally induced degradation of various device relevant multi cation hybrid perovskite films is performed using spectroscopic ellipsometry, for temperatures between 80 and 120 C. The studied compositions are a triple cation perovskite Cs0.05 MA0.17FA0.83 0.95Pb Br0.17I0.83 3, a Rb containing variant Rb0.05Cs0.05 MA0.17FA0.83 0.90Pb Br0.17I0.83 3, and a methylammonium free Rb0.05Cs0.10FA0.85PbI3 composition. A very wide combined spectral range of 200 nm to 25 amp; 956;m is covered by combining the data from two separate instruments. The relative changes in organic cation concentrations are quantified from the middle infrared molecular absorption bands, leveraging the use of point by point fitting for increased sensitivity. Additionally, the formation of PbI2 and non perovskite amp; 948; CsPbI3 phases is evidenced from Bruggemann effective medium fits to the visible and ultraviolet complex refractive indices. Methylammonium is almost completely depleted from the relevant compositions within 100 to 285 min of thermal annealing. The MA free perovskite degrades faster at intermediate temperatures, which is attributed to phase instability due to the formation of amp; 948; CsPbI3 in addition to PbI

    Cross-Tissue Transcriptomic Analysis Leveraging Machine Learning Approaches Identifies New Biomarkers for Rheumatoid Arthritis

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    There is an urgent need to identify biomarkers for diagnosis and disease activity monitoring in rheumatoid arthritis (RA). We leveraged publicly available microarray gene expression data in the NCBI GEO database for whole blood (N=1,885) and synovial (N=284) tissues from RA patients and healthy controls. We developed a robust machine learning feature selection pipeline with validation on five independent datasets culminating in 13 genes: TNFAIP6, S100A8, TNFSF10, DRAM1, LY96, QPCT, KYNU, ENTPD1, CLIC1, ATP6V0E1, HSP90AB1, NCL and CIRBP which define the RA score and demonstrate its clinical utility: the score tracks the disease activity DAS28 (p = 7e-9), distinguishes osteoarthritis (OA) from RA (OR 0.57, p = 8e-10) and polyJIA from healthy controls (OR 1.15, p = 2e-4) and monitors treatment effect in RA (p = 2e-4). Finally, the immunoblotting analysis of six proteins on an independent cohort confirmed two proteins, TNFAIP6/TSG6 and HSP90AB1/HSP90

    Slot Die Coated Triple Halide Perovskites for Efficient and Scalable Perovskite Silicon Tandem Solar Cells

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    Wide bandgap halide perovskite materials show promising potential to pair with silicon bottom cells. To date, most efficient wide bandgap perovskites layers are fabricated by spin coating, which is difficult to scale up. Here, we report on slot die coating for an efficient, 1.68 eV wide bandgap triple halide 3halide perovskite absorber, Cs0.22FA0.78 Pb I0.85Br0.15 3 5 mol MAPbCl3. A suitable solvent system is designed specifically for the slot die coating technique. We demonstrate that our fabrication route is suitable for tandem solar cells without phase segregation. The slot die coated wet halide perovskite is dried by a nitrogen N2 knife with high reproducibility and avoiding antisolvents. We explore varying annealing conditions and identify parameters allowing crystallization of the perovskite film into large grains reducing charge collection losses and enabling higher current density. At 150 C, an optimized trade off between crystallization and the PbI2 aggregates on the film s top surface is found. Thus, we improve the cell stability and performance of both single junction cells and tandems. Combining the 3halide top cells with a 120 amp; 956;m thin saw damage etched commercial Czochralski industrial wafer, a 2 terminal monolithic tandem solar cell with a PCE of 25.2 on a 1 cm2 active area is demonstrated with fully scalable processe

    21.6 efficient Monolithic Perovskite Cu In,Ga Se2 Tandem Solar Cells with Thin Conformal Hole Transport Layers for Integration on Rough Bottom Cell Surfaces

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    Perovskite based tandem solar cells can increase the power conversion efficiency PCE of conventional single junction photovoltaic devices. Here, we present monolithic perovskite CIGSe tandem solar cells with a perovskite top cell fabricated directly on an as grown, rough CIGSe bottom cell. To prevent potential shunting due to the rough CIGSe surface, a thin NiOx layer is conformally deposited via atomic layer deposition on the front contact of the CIGSe bottom cell. The performance is further improved by an additional layer of the polymer PTAA at the NiOx perovskite interface. This hole transport bilayer enables a 21.6 stabilized PCE of the tandem device at amp; 8764;0.8 cm2 active area. We use TEM EDX measurements to investigate the deposition uniformity and conformality of the NiOx and PTAA layers. By absolute photoluminescence measurements, the contribution of the individual subcells to the tandem VOC is determined, revealing that further fine tuning of the recombination layers might improve the tandem VOC. Finally, on the basis of the obtained results, we give guidelines to improve monolithic perovskite CIGSe tandems toward predicted PCE estimates above 3

    An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

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    Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences

    Micro-ribonucleic acid-155 is a direct target of Meis1, but not a driver in acute myeloid leukemia

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    Micro-ribonucleic acid-155 (miR-155) is one of the first described oncogenic miRNAs. Although multiple direct targets of miR-155 have been identified, it is not clear how it contributes to the pathogenesis of acute myeloid leukemia. We found miR-155 to be a direct target of Meis1 in murine Hoxa9/Meis1 induced acute myeloid leukemia. The additional overexpression of miR-155 accelerated the formation of acute myeloid leukemia in Hoxa9 as well as in Hoxa9/Meis1 cells However, in the absence or following the removal of miR-155, leukemia onset and progression were unaffected. Although miR-155 accelerated growth and homing in addition to impairing differentiation, our data underscore the pathophysiological relevance of miR-155 as an accelerator rather than a driver of leukemogenesis. This further highlights the complexity of the oncogenic program of Meis1 to compensate for the loss of a potent oncogene such as miR-155. These findings are highly relevant to current and developing approaches for targeting miR-155 in acute myeloid leukemia

    Subcell Operation and Long Term Stability Analysis of Perovskite Based Tandem Solar Cells Using a Bichromatic Light Emitting Diode Light Source

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    In monolithic tandem solar cells, current voltage J V characteristics of subcells provide invaluable information about their quality and tandem operation. However, accessing the subcell J Vs is challenging and requires sophisticated spectral methods. Herein, a customized, bichromatic light emitting diode setup BCLED for in depth analysis of tandem solar cells, suitable for subcell operation analysis, and long term stability testing is presented. For this, two spectrally independent LED arrays are used to selectively bias the two subcells. The power of the developed setup is demonstrated by successfully disentangling the tandem J V curve into subcell J V curves. The method is based on a one diode model for each subcell and is validated by electrical simulations. Afterward, it is used on a fabricated 27.6 efficient perovskite silicon tandem device, resulting in great agreement with the measured J V curve. Therefore, the BCLED setup is a versatile tool, suitable for subcell characteristics and long term stability analysis of tandem solar cell

    An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

    Get PDF
    Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42, 400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences. © 2021, The Author(s)
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