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Highly Efficient Wide Bandgap Perovskite Solar Cells With Tunneling Junction by Self Assembled 2D Dielectric Layer
Get PDFReducing non radiative recombination and addressing band alignment mismatches at interfaces remain major challenges in achieving high performance wide bandgap perovskite solar cells. This study proposes the self organization of a thin two dimensional 2D perovskite BA2PbBr4 layer beneath a wide bandgap three dimensional 3D perovskite Cs0.17FA0.83Pb I0.6Br0.4 3, forming a 2D 3D bilayer structure on a tin oxide SnO2 layer. This process is driven by interactions between the oxygen vacancies on the SnO2 surface and hydrogen atoms of the n butylammonium cation, aiding the self assembly of the BA2PbBr4 2D layer. The 2D perovskite acts as a tunneling layer between SnO2 and the 3D perovskite, neutralizing the energy level mismatch and reducing non radiative recombination. This results in high power conversion efficiencies of 21.54 and 19.16 for wide bandgap perovskite solar cells with bandgaps of 1.7 and 1.8 eV, with open circuit voltages over 1.3 V under 1 Sun illumination. Furthermore, an impressive efficiency of over 43 is achieved under indoor conditions, specifically under 200 lux white light emitting diode light, yielding an output voltage exceeding 1 V. The device also demonstrates enhanced stability, lasting up to 1,200 hour
Nonfullerene Self Assembled Monolayers As Electron Selective Contacts for n i p Perovskite Solar Cells
Get PDFOrganic, nonfullerene semiconductors capable of self assembly and composed of either anthraquinone AQ or naphthalenediimide NDI central fragments have been designed as electron selective materials for n i p perovskite solar cells PSCs . Both types of self assembled monolayer SAM molecules contain phosphonic acid as an anchoring group, allowing covalent binding with indium tin oxide ITO surfaces. In particular, the NDI based SAMs showed a more homogeneous anchoring on the ITO substrate and a stronger band bending at the ITO SAM perovskite interface than AQ based SAMs. As a result, low temperature processed n i p PSCs with NDI SAMs as an electron selective bottom contact showed a maximum power conversion efficiency PCE of 21.5 , representing the highest PCE among n i p PSCs with organic electron transporting layers ETLs . In addition, our NDI SAM based devices demonstrate substantially improved long term stability under operating temperature conditions when compared to devices using SnO2 as the ET
Thermal Disorder Induced Strain and Carrier Localization Activate Reverse Halide Segregation
Get PDFThe reversal of halide ions is studied under various conditions. However, the underlying mechanism of heat induced reversal remains unclear. This work finds that dynamic disorder induced localization of self trapped polarons and thermal disorder induced strain TDIS can be co acting drivers of reverse segregation. Localization of polarons results in an order of magnitude decrease in excess carrier density polaron population , causing a reduced impact of the light induced strain LIS responsible for segregation on the perovskite framework. Meanwhile, exposing the lattice to TDIS exceeding the LIS can eliminate the photoexcitation induced strain gradient, as thermal fluctuations of the lattice can mask the LIS strain. Under continuous 0.1 W cm amp; 8315;2 illumination upon segregation , the strain disorder is estimated to be 0.14 , while at 80 C under dark conditions, the strain is 0.23 . However, in situ heating of the segregated film to 80 C under continuous illumination upon reversal increases the total strain disorder to 0.25 , where TDIS is likely to have a dominant contribution. Therefore, the contribution of entropy to the system s free energy is likely to dominate, respectively. Various temperature dependent in situ measurements and simulations further support the results. These findings highlight the importance of strain homogenization for designing stable perovskites under real world operating condition
Synergistic Engineering of Dopant and Support of Ru Oxide Catalyst Enables Ultrahigh Performance for Acidic Oxygen Evolution
No full textActive and robust electrocatalysts for acidic oxygen evolution reaction OER are of crucial importance for efficient proton exchange membrane water electrolyzer PEM WE . Ruthenium Ru oxide has attracted considerable attention due to its high activity. However, the unsatisfying stability of Ru oxide in acidic OER environments hinders the application. Here, Ce doped RuO2 nanoparticles are designed and supported on Co N C material Ce RuO2 CoNC for acidic OER. It is demonstrated that Ce RuO2 CoNC delivers a super low overpotential of 150 mV and an excellent stability of 1000 h at 10 mA cm amp; 8722;2, outperforming most previously reported Ru based catalysts. The mass activity is estimated as 2365.5 AgRu amp; 8722;1 at 1.5 V vs RHE , representing amp; 8776;2 advance compared to the best prior study. Furthermore, applied in a single cell PEM WE device, it can steadily operate for 1000 h at 200 mA cm amp; 8722;2. The studies show that Ce doping and Co N C support synergistically enhance the activity and stability of Ru oxide by optimizing the free energies of OER intermediates and suppressing the dissolution of R
Angle resolved photoemission of topological materials
No full textTopological materials have gained significant attention in condensed matter physics due to their unique electronic and transport properties. Three dimensional 3D topological materials are characterized by robust electronic states that are protected by symmetries and exhibit peculiar spin textures. They offer a rich platform for future information technology including spintronics and topological quantum computing. Here, we review the investigation by angle resolved photoelectron spectroscopy ARPES of topological phases such as strong topological insulators, topological crystalline insulators, magnetic topological insulators, and 3D Dirac, Weyl, nodal, and chiral semimetals and address the status of correlated topological insulators and topological superconductors. A special emphasis is laid on examples from the transition metal dichalcogenide family. Moreover, insights from ultrafast pump probe experiments are reviewed and a brief outlook is provide
Subsurface Single Atom Catalyst Enabled by Mechanochemical Synthesis for Oxidation Chemistry
No full textSingle atom catalysts have garnered significant attention due to their exceptional atom utilization and unique properties. However, the practical application of these catalysts is often impeded by challenges such as sintering induced instability and poisoning of isolated atoms due to strong gas adsorption. In this study, we employed the mechanochemical method to insert single Cu atoms into the subsurface of Fe2O3 support. By manipulating the location of single atoms at the surface or subsurface, catalysts with distinct adsorption properties and reaction mechanisms can be achieved. It was observed that the subsurface Cu single atoms in Fe2O3 remained isolated under both oxidation and reduction environments, whereas surface Cu single atoms on Fe2O3 experienced sintering under reduction conditions. The unique properties of these subsurface single atom catalysts call for innovations and new understandings in catalyst desig
Scalable Fabrication of Neuromorphic Devices Using Inkjet Printing for the Deposition of Organic Mixed Ionic Electronic Conductor
Get PDFRecent advancements in artificial intelligence AI have highlighted the critical need for energy efficient hardware solutions, especially in edge computing applications. However, traditional AI approaches are plagued by significant power consumption. In response, researchers have turned to biomimetic strategies, drawing inspiration from the ion mediated operating principle of biological synapses, to develop organic neuromorphic devices as promising alternatives. Organic mixed ionic electronic conductor OMIEC materials have emerged as particularly noteworthy in this field, due to their potential for enhancing neuromorphic computing capabilities. Together with device performance, it is crucial to select devices that allow fabrication via scalable techniques. This study investigates the fabrication of OMIEC based neuromorphic devices using inkjet printing, providing a scalable and material efficient approach. Employing a commercially available polymer mixed ionic electronic conductor BTEM PPV and a lithium salt, inkjet printed devices exhibit performance comparable to those fabricated via traditional spin coating methods. These two terminal neuromorphic devices demonstrate functionality analogous to literature known devices and demonstrate promising frequency dependent short term plasticity. Furthermore, comparative studies with previous light emitting electrochemical cells LECs and neuromorphic OMIEC devices validate the efficacy of inkjet printing as a potential fabrication technique. The findings suggest that inkjet printing is suitable for large scale production, offering reproducible and stable fabrication processes. By adopting the OMIEC material system, inkjet printing holds the potential for further enhancing device performance and functionality. Overall, this study underscores the viability of inkjet printing as a scalable fabrication method for OMIEC based neuromorphic devices, paving the way for advancements in AI hardwar
Gewellte Graphen Nanostreifen mit Periodischen Achtgliedrigen Ringen für Lichtemittierende Elektrochemische Zellen
No full textPräzisions Graphen Nanostreifen GNS, engl. GNR bieten charakteristische physikalisch chemische Eigenschaften, die in hohem Ma e von ihrer geometrischen Topologie abhängen, und bergen damit gro es Potenzial für Anwendungen in der kohlenstoffbasierten Optoelektronik und Spintronik. Während die Kontrolle der Randstruktur und Breite eine beliebte Strategie für die Entwicklung der optoelektronischen Eigenschaften von GNRs ist, sind nicht Sechsring haltige GNRs aufgrund synthetischer Herausforderungen noch wenig erforscht, obwohl sie ein ebenso gro es Potenzial für ma geschneiderte Eigenschaften bieten. In diesem Artikel berichten wir über die Synthese eines gewellten GNR engl. wGNR , in dessen Kohlenstoffgerüst periodisch achtgliedrige Ringe eingebettet sind. Dies wurde durch eine A2B2 Diels Alder Polymerisation zwischen Dibenzocyclooctadiin 6 und einem Dicyclopenta[e,l]pyren 5,11 dion Derivat 8 erreicht, gefolgt von einer selektiven Scholl Reaktion des erhaltenen Leiter Typ Polymervorläufers engl. LTP . Der erhaltene wGNR mit einer Länge von bis zu 30 amp; 8197;nm wurde durch Festkörper amp; 8197;NMR , FT IR , Raman und UV Vis Spektroskopie, und mit Hilfe von DFT Berechnungen eingehend charakterisiert. Die nicht planare Geometrie des wGNR verhindert effizient die amp; 960; amp; 960; Aggregation zwischen den Streifen, was zu Photolumineszenz in Lösung führt. Folglich können die wGNR als emittierende Schicht für organische elektrochemisch Licht emittierende Zellen engl. OLECs fungieren und bieten einen Konzeptnachweis für die Implementierung lumineszierender GNRs in optoelektronische Geräte. Die schnell reagierenden OLECs, die wGNR verwenden, werden den Weg für Fortschritte in der OLEC Technologie und anderen optoelektronischen Geräten ebne
Coupling cellular drug target engagement to downstream pharmacology with CeTEAM
No full textCellular target engagement technologies enable quantification of intracellular drug binding; however, simultaneous assessment of drug associated phenotypes has proven challenging. Here, we present cellular target engagement by accumulation of mutant as a platform that can concomitantly evaluate drug target interactions and phenotypic responses using conditionally stabilized drug biosensors. We observe that drug responsive proteotypes are prevalent among reported mutants of known drug targets. Compatible mutants appear to follow structural and biophysical logic that permits intra protein and paralogous expansion of the biosensor pool. We then apply our method to uncouple target engagement from divergent cellular activities of MutT homolog 1 MTH1 inhibitors, dissect Nudix hydrolase 15 NUDT15 associated thiopurine metabolism with the R139C pharmacogenetic variant, and profile the dynamics of poly ADP ribose polymerase 1 2 PARP1 2 binding and DNA trapping by PARP inhibitors PARPi . Further, PARP1 derived biosensors facilitated high throughput screening for PARP1 binders, as well as multimodal ex vivo analysis and non invasive tracking of PARPi binding in live animals. This approach can facilitate holistic assessment of drug target engagement by bridging drug binding events and their biological consequence
Revised Hamiltonian near third integer resonance and implications for an electron storage ring
No full textIn electron storage rings, an accurate description of particle dynamics near third integer resonance is crucial for various applications. The conventional approach is to extrapolate far resonance dynamics to near resonance, but the difficulty arises because the nonlinear detuning parameter diverges at this critical point. Here we derive, via a suitable application of the canonical perturbation theory, a revised detuning parameter that is well behaved near resonance. The resultant theory accurately describes the morphology of resonance islands for a wide range of parameter space and facilitates its optimizatio