Influence of the Polymer Structure and its Crystallization on the Interface Resistance in Polymer-LATP and Polymer-LLZO Hybrid Electrolytes

For many years, composite electrolytes (CEs) consisting of a mixture of inorganic solid electrolytes (ISEs) and polymer electrolytes (PEs) have been investigated as promising materials for the scalable production of solid-state batteries (SSBs). It is believed that CEs can overcome limitations of the single components, namely the low room-temperature conductivity and lithium ion transference number of PEs and the poor mechanical properties and high temperature processing necessary for ISE ceramics. To facilitate ion transport in the CE between the electrodes a low and stable charge transfer resistance between PEs and ISEs is required. In this study, we investigate by means of electrochemical impedance spectroscopy (EIS) how polymer crystallinity influences the charge-transfer resistance of hetero-ionic interfaces between polyethylene oxide (PEO)-based electrolytes and Li$_{1.5}$Al$_{0.5}$Ti$_{1.5}$(PO$_4$)$_3$ (LATP) as well as Li$_{6.25}$Al$_{0.25}$La$_3$Zr$_2$O$_{12}$ (LLZO) as ISEs. Crystallization of PEO based electrolytes below their melting temperature leads to an increased charge-transfer resistance. On the other hand, electrolytes based on the amorphous poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether (PTG) do not show an increased charge transfer resistance. Finally, the conductivity of ISE-rich CEs is measured as a function of their temperature and composition for elucidating how the interface resistance influences charge transport in ISE-rich composite electrolytes

Working Principle of an Ionic Liquid Interlayer During Pressureless Lithium Stripping on Li6.25_{6.25}Al0.25_{0.25}La3_{3}Zr2_{2}O12_{12} (LLZO) Garnet-Type Solid Electrolyte

Solid-state-batteries employing lithium metal anodes promise high theoretical energy and power densities. However, morphological instability occurring at the lithium/solid–electrolyte interface when stripping and plating lithium during cell cycling needs to be mitigated. Vacancy diffusion in lithium metal is not sufficiently fast to prevent pore formation at the interface above a certain current density during stripping. Applied pressure of several MPa can prevent pore formation, but this is not conducive to practical application. This work investigates the concept of ionic liquids as “self-adjusting” interlayers to compensate morphological changes of the lithium anode while avoiding the use of external pressure. A clear improvement of the lithium dissolution process is observed as it is possible to continuously strip more than 70 μm lithium (i. e., 15 mAh cm$^{−2}$ charge) without the need for external pressure during assembly and electrochemical testing of the system. The impedance of the investigated electrodes is analyzed in detail, and contributions of the different interfaces are evaluated. The conclusions are corroborated with morphology studies using cryo-FIB-SEM and chemical analysis using XPS. This improves the understanding of the impedance response and lithium stripping in electrodes employing liquid interlayers, acting as a stepping-stone for future optimization

Adherence to Antihypertensive Drugs Assessed by Hyphenated High-Resolution Mass Spectrometry Analysis of Oral Fluids

Background It is currently unknown if antihypertensive drugs can be monitored in oral fluid (OF) using liquid chromatography coupled to high-resolution mass spectrometry. Methods and Results We assessed adherence using liquid chromatography coupled to high-resolution mass spectrometry in OF, plasma, and urine of 56 consecutive patients with hypertension referred to a tertiary hypertension unit. Of these patients, 59% were completely adherent (all drugs detectable in urine), whereas 29% and 13% were partially adherent (1 drug not detectable in urine) or nonadherent (>1 drug not detectable in urine), respectively. Adherent patients were on fewer antihypertensive drugs (P=0.001), had fewer daily drug doses (P=0.012), and had lower 24-hour ambulatory systolic (P=0.012) and diastolic (P=0.009) blood pressures than nonadherent or partially adherent patients. Most drugs were detected in urine compared with plasma and OF (181 versus 119 versus 88; P=0.001). Compared with urine and plasma, detection rates of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and diuretics were lower in OF. There was no difference in the frequency of detecting β blockers (P=1.0) and calcium channel blockers (P=0.063) when comparing OF with urine. There was no difference in the number of calcium channel blockers (P=0.727), β blockers (P=1.000), thiazide diuretics (P=0.125), and α-2 agonists (P=0.125) identified between OF and plasma. Conclusions This study shows the feasibility of drug adherence testing for several antihypertensive drugs, especially those without acidic components, in OF, with a similar recovery compared with plasma. Therefore, drug adherence testing in OF should be further explored as a noninvasive approach, which can easily be performed in an "out-of-office" setting

Designing Cathodes and Cathode Active Materials for Solid‐State Batteries

Solid-state batteries (SSBs) currently attract great attention as a potentially safe electrochemical high-energy storage concept. However, several issues still prevent SSBs from outperforming today\u27s lithium-ion batteries based on liquid electrolytes. One major challenge is related to the design of cathode active materials (CAMs) that are compatible with the superionic solid electrolytes (SEs) of interest. This perspective, gives a brief overview of the required properties and possible challenges for inorganic CAMs employed in SSBs, and describes state-of-the art solutions. In particular, the issue of tailoring CAMs is structured into challenges arising on the cathode-, particle-, and interface-level, related to microstructural, (chemo-)mechanical, and (electro-)chemical interplay of CAMs with SEs, and finally guidelines for future CAM development for SSBs are proposed

Exciton-Phonon Interactions Govern Charge-Transfer-State Dynamics in CdSe/CdTe Two-Dimensional Colloidal Heterostructures.

CdSe/CdTe core-crown type-II nanoplatelet heterostructures are two-dimensional semiconductors that have attracted interest for use in light-emitting technologies due to their ease of fabrication, outstanding emission yields, and tunable properties. Despite this, the exciton dynamics of these complex materials, and in particular how they are influenced by phonons, is not yet well understood. Here, we use a combination of femtosecond vibrational spectroscopy, temperature-resolved photoluminescence (PL), and temperature-dependent structural measurements to investigate CdSe/CdTe nanoplatelets with a thickness of four monolayers. We show that charge-transfer (CT) excitons across the CdSe/CdTe interface are formed on two distinct time scales: initially from an ultrafast (∼70 fs) electron transfer and then on longer time scales (∼5 ps) from the diffusion of domain excitons to the interface. We find that the CT excitons are influenced by an interfacial phonon mode at ∼120 cm-1, which localizes them to the interface. Using low-temperature PL spectroscopy we reveal that this same phonon mode is the dominant mechanism in broadening the CT PL. On cooling to 4 K, the total PL quantum yield reaches close to unity, with an ∼85% contribution from CT emission and the remainder from an emissive sub-band-gap state. At room temperature, incomplete diffusion of domain excitons to the interface and scattering between CT excitons and phonons limit the PL quantum yield to ∼50%. Our results provide a detailed picture of the nature of exciton-phonon interactions at the interfaces of 2D heterostructures and explain both the broad shape of the CT PL spectrum and the origin of PL quantum yield losses. Furthermore, they suggest that to maximize the PL quantum yield both improved engineering of the interfacial crystal structure and diffusion of domain excitons to the interface, e.g., by altering the relative core/crown size, are required.We acknowledge financial support from the EPSRC [EP/M005143/1] and Winton Program for the Physics of Sustainability. The work of SI is supported by the program ANR JCJC NannoDoSe

Photon recycling in lead iodide perovskite solar cells.

Lead-halide perovskites have emerged as high-performance photovoltaic materials. We mapped the propagation of photogenerated luminescence and charges from a local photoexcitation spot in thin films of lead tri-iodide perovskites. We observed light emission at distances of ≥50 micrometers and found that the peak of the internal photon spectrum red-shifts from 765 to ≥800 nanometers. We used a lateral-contact solar cell with selective electron- and hole-collecting contacts and observed that charge extraction for photoexcitation >50 micrometers away from the contacts arose from repeated recycling between photons and electron-hole pairs. Thus, energy transport is not limited by diffusive charge transport but can occur over long distances through multiple absorption-diffusion-emission events. This process creates high excitation densities within the perovskite layer and allows high open-circuit voltages.The authors acknowledge financial support from the Engineering and Physical Sciences Research Council of the UK (EPSRC) and King Abdulaziz City for Science and Technology (KACST). L.M.P.O. and H.J.B. also thank the Nano doctoral training center (NanoDTC) for financial support. M.S., M.V. and J.M.R. thank the Winton programme for the physics of sustainability. M.C.Q would like to thank the Marie Curie Actions (FP7-PEOPLE-IEF2013) for funding. M.A.J. thanks Nyak Technology Ltd for PhD scholarship and B.E. acknowledges the Foundation for Fundamental Research on Matter (FOM), which is part of the Netherlands Organization for Scientific Research (NWO). F.D. acknowledges funding through a Herchel Smith Research Fellowship. We acknowledge Prof. Henning Sirringhaus, Prof. Neil Greenham, Prof. Ullrich Steiner, Dr. Erwin Reisner and Prof. Richard Phillips for providing support and access to their facilities.This is the author accepted manuscript. The final version is available from the American Association for the Advancement of Science via http://dx.doi.org/10.1126/science.aaf116

A gain-of-function TBX20 mutation causes congenital atrial septal defects, patent foramen ovale and cardiac valve defects

BACKGROUND: Ostium secundum atrial septal defects (ASDII) account for approximately 10% of all congenital heart defects (CHD) and mutations in cardiac transcription factors, including TBX20, were identified as an underlying cause for ASDII. However, very little is known about disease penetrance in families and functional consequences of inherited TBX20 mutations. METHODS: The coding region of TBX20 was directly sequenced in 170 ASDII patients. Functional consequences of one novel mutation were investigated by surface plasmon resonance, CD spectropolarymetry, fluorescence spectrophotometry, luciferase assay and chromatin immunoprecipitation. RESULTS: We found a novel mutation in a highly conserved residue in the T-box DNA-binding domain (I121M) segregating with CHD in a three generation kindred. Four mutation carriers revealed cardiac phenotypes in terms of cribriform ASDII, large patent foramen ovale or cardiac valve defects. Interestingly, tertiary hydrophobic interactions within the mutant TBX20 T-box were significantly altered leading to a more dynamic structure of the protein. Moreover, Tbx20-I121M resulted in a significantly enhanced transcriptional activity, which was further increased in the presence of co-transcription factors GATA4/5 and NKX2-5. Occupancy of DNA binding sites on target genes was also increased. CONCLUSIONS: We suggest that TBX20-I121M adopts a more fluid tertiary structure leading to enhanced interactions with cofactors and more stable transcriptional complexes on target DNA sequences. Our data, combined with that of others, suggest that human ASDII may be related to loss- as well as gain-of-function TBX20 mutations

Direct Bandgap Behavior in Rashba-Type Metal Halide Perovskites.

The generation and recombination of charge carriers in semiconductors through photons controls photovoltaic and light-emitting diode operation. Understanding of these processes in hybrid perovskites has advanced, but remains incomplete. Using femtosecond transient absorption and photoluminescence, it is observed that the luminescence signal shows a rise over 2 ps, while initially hot photogenerated carriers cool to the band edge. This indicates that the luminescence from hot carriers is weaker than that of cold carriers, as expected from strongly radiative transitions in direct gap semiconductors. It is concluded that the electrons and holes show a strong overlap in momentum space, despite recent proposals that Rashba splitting leads to a band offset suppressing such an overlap. A number of possible resolutions to this, including lattice dynamics that remove the Rashba splitting at room temperature, and localization of luminescence events to length scales below 10 nm are considered.The authors acknowledge financial support from the Engineering and Physical Sciences Research Council of the UK (EPSRC). J.M.R. thanks the Winton Programme for the Physics of Sustainability (University of Cambridge). J.M.R. thanks the Cambridge Home European Scheme for financial support. B.M. thanks Robinson College and the Cambridge Philosophical Society for a Henslow Research Fellowship. F.D. acknowledges funding from a Herchel Smith Research Fellowship and a Winton Advanced Research Fellowship