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Monolithic Series Interconnected Two Terminal Perovskite CIGSe Tandem Solar Cells Voltage Matched or Current Matched
No full textPerovskite CIGSe tandem solar cells represent a promising path toward high efficiency and low cost photovoltaics. Typically, tandem solar cells are designed in a two terminal current matched 2T CM configuration. However, this design suffers from limitations related to spectral variations, which can lead to current mismatch and reduced energy yield. An alternative is the four terminal 4T configuration, where top and bottom cells operate independently, but this increases system complexity and cost. The two terminal voltage matched 2T VM configuration overcomes these challenges by matching the voltages of the top and bottom cells, making 2T VM tandems less sensitive to current mismatch while maintaining a simpler system design. This study explores the potential of monolithically interconnected 2T VM perovskite CIGSe tandems, focusing on laser patterning techniques for interconnecting the layers. A specific and promising interconnection approach is presented, and the necessary process steps are analyzed to evaluate how they can be adapted from well established laser patterning techniques. Our findings indicate that the 2T VM configuration offers a robust and cost effective solution for achieving high energy yields with minimal complexity, positioning it as a viable alternative for next generation thin film solar technologie
Realizing high capacity and low strain manganese based sodium cathode by regulating the doping sites of Mg with a post doping approach
No full textFe Mn based P2 type layered oxides consistently encounter challenges with suboptimal electrochemical cyclability. Here, this work reports a post doping treatment approach, successfully leading to the introduction of Mg2 into the Na layer as a priority, resulting in a significant improvement in both the capacity and cycle stability. The advanced structural characterization technology reveals that Mg2 located in the Na layer play a crucial pillar role in the cycling process. Furthermore, the presence of Mg2 on Na site can reduce the valence state of Mn and enhance the capacity. The [Na0.67Mg0.024 Fe0.2Mn0.8Mg0.016 ]1 1 0.016 O2 cathode treated by post doping has a high reversible specific capacity of 179 mAh g amp; 8722;1 at 0.2C between 2.0 V and 4.0 V. Even at the high rate of 5C, it still maintains a capacity retention of 67.4 after 500 cycles. This study offers a novel viewpoint for the design of cathode materials with high capacity and high cycle stabilit
Double Tips for In Plane Polarized Near Field Microscopy and Spectroscopy
Get PDFNear field optical microscopy and spectroscopy provide high resolution imaging below the diffraction limit, crucial in physics, chemistry, and biology for studying molecules, nanoparticles, and viruses. These techniques use a sharp metallic tip of an atomic force microscope AFM to enhance incoming and scattered light by excited near fields at the tip apex, leading to high sensitivity and a spatial resolution of a few nanometers. However, this restricts the near field orientation to out of plane polarization, limiting optical polarization choices. We introduce double tips that offer in plane polarization for enhanced imaging and spectroscopy. These double tips provide superior enhancement over single tips, although with a slightly lower spatial resolution amp; 8764;30 nm . They enable advanced studies of nanotubes, graphene defects, and transition metal dichalcogenides, benefiting from polarization control. The double tips allow varied polarization in tip enhanced Raman scattering and selective excitation of transverse electric and magnetic polaritons, expanding the range of nanoscale samples that can be studie
Influence of Chromium Carbide Derived Carbon Support and Ceria Nanocrystals on Pt CeO2 C Catalysts for Fuel Cell Applications
Get PDFECS Advances The Electrochemical Society ECS logo. The following article is Open access Influence of Chromium Carbide Derived Carbon Support and Ceria Nanocrystals on Pt CeO2 C Catalysts for Fuel Cell Applications Huy Qu Vinh Nguyen, Jaak Nerut, Heili Kasuk, Thomas Thomberg, Tavo Romann, Jaan Aruväli, Marian Külaviir, Peeter Paaver, Zdravko Kochovski, Eneli Härk Published 27 May 2024 2024 The Author s . Published on behalf of The Electrochemical Society by IOP Publishing Limited. ECS Advances, Volume 3, Number 2 Citation Huy Qu Vinh Nguyen et al 2024 ECS Adv. 3 024505 DOI 10.1149 2754 2734 ad456c Download Article PDF Article metrics 490 Total downloads Share this article Abstract The influence of different synthesis parameters on CeO2 and Pt nanoparticle NP deposition on Ketjenblack carbon C KB was examined. The Pt NP diameter 3.1 4.1 nm was not influenced by CeO2 synthesis parameters. The CeO2 NPs synthesized using ultrasound sonication contribute to a better durability of the Pt CeO2 C against CO poisoning. In contrast, CeO2 synthesized using the microwave heating method contributes to better methanol oxidation reaction MOR activity at low electrode potential. Synthesis parameters of CeO2 and Pt NPs developed for the C KB based catalysts were applied for C Cr3C2 based catalysts. The Pt NP diameter of C Cr3C2 based catalysts was slightly higher 7.2 nm as some Pt NPs were agglomerated. The C Cr3C2 support facilitates the MOR and CO stripping, especially in the case of the Pt C on C Cr3C2 support. The MOR activity at 0.85 V of Pt NPs on the C Cr3C2 support is as good as the MOR activity for the best Pt CeO2 on the C KB support. The C Cr3C2 support also improves the CO removal from the Pt surface. All the synthesized catalysts had better MOR activity than the commercial Pt C Vulcan catalyst. The oxygen reduction reaction activity of Pt CeO2 C catalysts with higher CeO2 content synthesized with the microwave heating method was very goo
SERS Spectra Indicate the Molecular Effects of 7 Nitrobenz 2 oxa 1,3 diazole NBD on Living Cells
Get PDF7 Nitrobenz 2 oxa 1,3 diazole NBD is a widely used fluorescent label for proteins, peptides, and lipids. Its chloride derivative, NBD Cl, can be highly reactive toward thiol and amine groups, forming stable fluorescent adducts. When labeling the ubiquitous lipid molecule ceramide, NBD ceramide NBDCER aids in visualizing sphingolipid metabolism in cells. This study investigates intracellular molecular changes induced by NBD Cl and NBDCER using surface enhanced Raman scattering SERS . SERS spectra from the endolysosomal compartment of two cell lines, 3T3 fibroblast cells and J774 macrophage cells, obtained with gold nanoparticles as probes, reveal changes in the molecular composition and interactions under different incubation conditions. Applying the random forest RF based algorithm surrogate minimal depth SMD to the SERS data to identify important spectral classifiers and their relations, both NBD Cl and NBDCER are found to alter the biochemical makeup of the endolysosomal compartment. The data indicate significant structural and interaction changes in the molecular constituents of the cells that are in agreement with possible interference of the labels in the cellular metabolism and the reaction of NBD Cl with functional groups of cellular molecule
Modifying the Substrate Dependent Pd Fe2O3 Catalyst Support Synergism with ZnO Atomic Layer Deposition
No full textLow loading Pd supported on Fe2O3 nanoparticles was synthesized. A common nanocatalyst system with previously reported synergistic enhancement of reactivity that is attributed to the electronic interactions between Pd and the Fe2O3 support. Fe2O3 selective precoalescence overcoating with ZnO atomic layer deposition ALD , using Zn CH2CH3 2 and H2O as precursors, dampens competitive hydrogenation reactivity at Fe2O3 based sites. The result is enhanced efficiency at the low loading but high reactivity Pd sites. While this increases catalyst efficiency toward most aqueous redox reactions tested, it suppresses reactivity toward polyaromatic core substrates. X ray photoelectron spectroscopy XPS and ultraviolet photoelectron spectroscopy UPS show minimal electronic impacts for the ZnO overcoat on the Pd particles, implying a predominantly physical site blocking effect as the reason for the modified reactivity. This serves as a proof ofconcept of not only stabilizing supported nanocatalysts but also altering reactivity with ultrathin ALD overcoats. The results point to a facile ALD route for selective enhancement of reactivity for low loading Pd based supported nanocatalyst
Probing precipitation in aluminium alloys during linear cooling via in situ differential scanning calorimetry and electrical resistivity measurement
Get PDFInvestigating precipitation processes in aluminium alloys during cooling from the solutionising temperature is important because the level of solute supersaturation and the presence of pre precipitated solutes determine the response to the subsequent age hardening step. Differential scanning calorimetry has been developed to a suitable method to follow precipitation over a wide range of cooling rates. We develop a device that allows us to measure electrical resistivity in situ during the quenching of alloy samples from the solutionising temperature. A procedure is formulated that allows us to separate the signal related to precipitation from the large background caused by the temperature dependence of electrical resistivity. Application to an aluminium alloy 6014 reveals a two stage precipitation reaction during cooling at rates between 1 and 20 K min 1, the first related to precipitation of the stable amp; 946; phase, the second due to the formation of various metastable phases. Comparison between resistivity and DSC signals measured at the same cooling rate shows very close correspondence between the two. Thus, in the future, both methods could be used in a complementary wa
A Perspective on Photocatalytic Synthesis of NH3, Urea, and Amino Acids by Nanomaterials Progress and Prospects
Get PDFA sustainable world is only possible when we are ready to deliver a net zero carbon emission energy sector. In this regard, we must not only consider more renewable energy resources but also find alternate paths for making some popular molecules like NH3 and urea for a lesser carbon footprint. This perspective article summarizes the recent progress of the photocatalytic synthesis of NH3, urea, and some amino acids using novel nanomaterials where we have focused on various approaches to catalyst design like metal oxides, metal sulfides, metal free catalysts, and biomimicking catalysts for ambient condition N2 activation. Later we discussed general reaction pathways, a detailed mechanistic overview, and future material layout for a sustainable approach towards N2 activatio
Competing gauge fields and entropically driven spin liquid to spin liquid transition in non Kramers pyrochlores
Get PDFCompeting interactions in magnetic systems frustrate the development of long range order, possibly down to absolute zero temperature, giving rise to a spin liquid. Gauge fields, akin to those used to describe the fundamental forces in the universe, are the mathematical objects of choice to describe spin liquids. In a model relevant to real magnetic pyrochlore materials, we uncover a spin liquid described by combined vector like and matrix like gauge fields. Classically, similarly to the liquid to liquid transition observed in some molecular liquids, this state disappears at low temperatures and gives way to a spin liquid with extensive entropy and with only the vector like field thermally fluctuating. Quantum mechanically, the ground state is a spin liquid described by both gauge fields. Gauge theories are powerful theoretical physics tools that allow complex phenomena to be reduced to simple principles and are used in both high energy and condensed matter physics. In the latter context, gauge theories are becoming increasingly popular for capturing the intricate spin correlations in spin liquids, exotic states of matter in which the dynamics of quantum spins never ceases, even at absolute zero temperature. We consider a spin system on a three dimensional pyrochlore lattice where emergent gauge fields not only describe the spin liquid behavior at zero temperature but crucially determine the system?s temperature evolution, with distinct gauge fields giving rise to different spin liquid phases in separate temperature regimes. Focusing first on classical spins, in an intermediate temperature regime, the system shows an unusual coexistence of emergent vector and tensor gauge fields where the former is known from classical spin ice systems while the latter has been associated with fractonic quasiparticles, a peculiar type of excitation with restricted mobility. Upon cooling, the system transitions into a low temperature phase where an entropic selection mechanism depopulates the degrees of freedom associated with the tensor gauge field, rendering the system spin ice like. We further provide numerical evidence that in the corresponding quantum model, a spin liquid with coexisting vector and tensor gauge fields has a finite window of stability in the parameter space of spin interactions down to zero temperature. Finally, we discuss the relevance of our findings for non Kramers magnetic pyrochlore material