Concentration dependence of resistance components in solutions containing dissolved Fe/Fe.

Electrolyte solutions containing Fe/Fe are suitable for liquid thermoelectric conversion devices (LTEs), because they are inexpensive materials and exhibit a high electrochemical Seebeck coefficient . Here, we investigated the concentration () dependence of resistance components, , solvent (), charge-transfer (), and diffusion () resistances, of dissolved-Fe/Fe-containing aqueous, methanol (MeOH), acetone, and propylene carbonate (PC) solutions. We found that the dependence of and are well reproduced by empirical formulas, and , where () is viscosity at .

Temperature switch of electrochemical Seebeck coefficient of Fe/Fe formation of [FeCl]/[FeCl].

The electrochemical Seebeck coefficient ( = d/d; and are the redox potential and temperature, respectively) is important parameter for thermoelectric conversion. Here, we found that of Fe/Fe in dimethyl sulfoxide (DMSO) with small amount of 19 M LiCl aqueous solution exhibits a crossover behavior from 1.4 mV K (20 °C ≤ ≤ 40 °C) to ≈0 mV K (50 °C ≤ ≤ 80 °C).

Control of Fe coordination by excess Cl in alcohol solutions.

We spectroscopically investigated coordination state of Fe in methanol (MeOH) and ethanol (EtOH) solutions against Cl concentration ([Cl]). In both the system, we observed characteristic absorption bands due to the FeCl complex at high-[Cl] region. In the MeOH system, the proportion () of [FeCl] exhibits a stationary value of 0.

Electron transfer phase transition and oxidization process in NaCoMn[Fe(CN)] (0.00 ≤ ≤ 1.60).

We investigated the phase diagram of NaCoMn[Fe(CN)] in the entire Na concentration range of 0.00 ≤ ≤ 1.60.

Chemical passivation of the under coordinated Pb defects in inverted planar perovskite solar cells via β-diketone Lewis base additives.

Hybrid organic-inorganic perovskite solar cells (PSCs) are promising new generations of solar cells, which is low in cost with high power conversion efficiency (PCE). However, PSCs suffer from structural defects generated from the under coordinated ions at the surface, which limits their photovoltaic performances. Herein we report, two β-diketone Lewis base additives 2,4-pentanedione and 3-methyl-2,4-nonanedione within the chlorobenzene anti-solvent to passivate the surface defects generated from the under coordinated Pb ions in CHNHPbI perovskite films.

In situ IR spectroscopy during oxidation process of cobalt Prussian blue analogues.

Cobalt Prussian blue analogues (Co-PBA; NaCo[Fe(CN)]), consisting of cyano-bridged transition metal network, -Fe-CN-Co-NC-Fe-, are promising cathode materials for Na-ion secondary batteries. In the oxidation process, oxidization of Fe and/or Co are compensated by Na deintercalation. Here, we investigated the oxidization process of three Co-PBAs by means of in situ infrared absorption (IR) spectroscopy.

Controllable Magnetic Proximity Effect and Charge Transfer in 2D Semiconductor and Double-Layered Perovskite Manganese Oxide van der Waals Heterostructure.

Optically generated excitonic states (excitons and trions) in transition metal dichalcogenides are highly sensitive to the electronic and magnetic properties of the materials underneath. Modulation and control of the excitonic states in a novel van der Waals (vdW) heterostructure of monolayer MoSe on double-layered perovskite Mn oxide ((La Nd ) Sr Mn O ) is demonstrated, wherein the Mn oxide transforms from a paramagnetic insulator to a ferromagnetic metal. A discontinuous change in the exciton photoluminescence intensity via dielectric screening is observed.

Aggregation tendency of guest Fe in NaCoFeO (x < 0.1) as investigated by systematic EXAFS analysis.

In transition metal (M) compounds, the partial substitution of the host transition metal (M) to guest one (M) is effective to improve the functionality. To microscopically comprehend the substitution effect, degree of distribution of M is crucial. Here, we propose that a systematic EXAFS analysis against the M concentration can reveal the spatial distribution of M.

Energy harvesting thermocell with use of phase transition.

A thermocell that consists of cathode and anode materials with different temperature coefficients (α = dV/dT) of the redox potential (V) can convert environmental thermal energy to electric energy via the so-called thermal charging effect. The output voltage V of the current thermocell, however, is still low (several tens mV) and depends on temperature, which are serious drawbacks for practical use of the device as an independent power supply. Here, we report that usage of phase transition material as electrode qualitatively improve the device performance.

The effect of 3d-electron configuration entropy on the temperature coefficient of redox potential in CoMn Prussian blue analogues.

Recently, it was reported that a thermocell can convert temperature into electrical energy by using the difference in the thermal coefficient (α ≡ dV/dT) of the redox potential (V) between the cathode and anode materials. Here, we systematically investigated α of NaxCo1-zMnz[Fe(CN)6]y (Co1-zMnz-PBA) against Mn concentration (z). The z-dependence of α is interpreted in terms of the 3d-electron configuration entropy (ΔS3d) of the redox site.

Thermal efficiency of a thermocell made of Prussian blue analogues.

Recently, it was reported that a thermocell can convert temperature into electric energy by using the difference in the thermal coefficient (α = dV/dT) of the redox potential (V) between the cathode and anode materials. Among battery materials, Prussian blue analogues (PBAs) are promising materials for thermocell, because α changes from approximately -0.3 mV/K in NaMn[Fe(CN)] 3.

Thermal Expansion in Layered Na MO.

Layered oxide Na MO (M: transition metal) is a promising cathode material for sodium-ion secondary battery. Crystal structure of O3- and P2-type Na MO with various M against temperature (T) was systematically investigated by synchrotron x-ray diffraction mainly focusing on the T-dependences of a- and c-axis lattice constants (a and c) and z coordinate (z) of oxygen. Using a hard-sphere model with minimum Madelung energy, we confirmed that c/a and z values in O3-type Na MO were reproduced.

Publisher Correction: Atomic scale imaging of magnetic circular dichroism by achromatic electron microscopy.

In Fig. 1 of the version of this Letter originally published, the word 'Subtract' was missing from the green box to the left of panel f. This has now been corrected in all versions of the Letter.

Atomic scale imaging of magnetic circular dichroism by achromatic electron microscopy.

In order to obtain a fundamental understanding of the interplay between charge, spin, orbital and lattice degrees of freedom in magnetic materials and to predict and control their physical properties, experimental techniques are required that are capable of accessing local magnetic information with atomic-scale spatial resolution. Here, we show that a combination of electron energy-loss magnetic chiral dichroism and chromatic-aberration-corrected transmission electron microscopy, which reduces the focal spread of inelastically scattered electrons by orders of magnitude when compared with the use of spherical aberration correction alone, can achieve atomic-scale imaging of magnetic circular dichroism and provide element-selective orbital and spin magnetic moments atomic plane by atomic plane. This unique capability, which we demonstrate for SrFeMoO, opens the door to local atomic-level studies of spin configurations in a multitude of materials that exhibit different types of magnetic coupling, thereby contributing to a detailed understanding of the physical origins of magnetic properties of materials at the highest spatial resolution.

Strong localization of oxidized Co state in cobalt-hexacyanoferrate.

Secondary batteries are important energy storage devices for a mobile equipment, an electric car, and a large-scale energy storage. Nevertheless, variation of the local electronic state of the battery materials in the charge (or oxidization) process are still unclear. Here, we investigated the local electronic state of cobalt-hexacyanoferrate (Na Co[Fe(CN)]), by means of resonant inelastic X-ray scattering (RIXS) with high energy resolution (~100 meV).

Invariant nature of substituted element in metal-hexacyanoferrate.

The chemical substitution of a transition metal (M) is an effective method to improve the functionality of materials. In order to design the highly functional materials, we first have to know the local structure and electronic state around the substituted element. Here, we systematically investigated the local structure and electronic state of the host (M ) and guest (M ) transition metals in metal-hexacyanoferrate (M-HCF), Na (M , M )[Fe(CN)] (1.

Local structures around the substituted elements in mixed layered oxides.

The chemical substitution of a transition metal (M) is an effective method to improve the functionality of a material, such as its electrochemical, magnetic, and dielectric properties. The substitution, however, causes local lattice distortion because the difference in the ionic radius (r) modifies the local interatomic distances. Here, we systematically investigated the local structures in the pure (x = 0.

In situ observation of macroscopic phase separation in cobalt hexacyanoferrate film.

Lithium-ion secondary batteries (LIBs) store electric energy via Li deintercalation from cathode materials. The Li deintercalation frequently drives a first-order phase transition of the cathode material as a result of the Li-ordering or Li-concentration effect and causes a phase separation (PS) into the Li-rich and Li-poor phases. Here, we performed an in situ microscopic investigation of the PS dynamics in thin films of cobalt hexacyanoferrate, LiCo[Fe(CN)], against Li deintercalation.

Na(+) diffusion kinetics in nanoporous metal-hexacyanoferrates.

Metal-hexacyanoferrates (metal-HCFs) are promising candidates for cathode materials of sodium-ion secondary batteries (SIBs). Here, we systematically investigated Na(+) diffusion constants (D) and the activation energies (Ea) of metal-HCFs against the framework size (= a/2). We found that the magnitude of D (Ea) systematically increases (decreases) with increases in a, indicating that steric hindrance plays a dominant role in Na(+) diffusion.

Carrier density effect on recombination in PTB7-based solar cell.

Organic solar cells (OSCs) are promising alternatives to the conventional inorganic solar cells due to their low-cost processing and compatibility with flexible substrates. The development of low band-gap polymer, e.g.

Fullerene mixing effect on carrier formation in bulk-hetero organic solar cell.

Organic solar cells (OSCs) with a bulk-heterojunction (BHJ) are promising energy conversion devices, because they are flexible and environmental-friendly, and can be fabricated by low-cost roll-to-roll process. Here, we systematically investigated the interrelations between photovoltaic properties and the domain morphology of the active layer in OSCs based on films of poly-(9,9-dioctylfluorene-co-bithiophene) (F8T2)/[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) blend annealed at various temperatures (Tan). The scanning transmission X-ray microscopy (STXM) revealed that fullerene mixing (ΦFullerene) in the polymer matrix decreases with increase in Tan while the domain size (L) is nearly independent of Tan.

Fast discharge process of layered cobalt oxides due to high Na⁺ diffusion.

Sodium ion secondary battery (SIB) is a low-cost and ubiquitous secondary battery for next-generation large-scale energy storage. The diffusion process of large Na(+) (ionic radius is 1.12 Å), however, is considered to be slower than that of small Li(+) (0.

Ultrafast cation intercalation in nanoporous nickel hexacyanoferrate.

Cation intercalation into nanoporous coordination polymers is utilized in, e.g., Li(+)/Na(+) secondary batteries, the decontamination of radioactive (137)Cs(+), and so on.

A sodium manganese ferrocyanide thin film for Na-ion batteries.

A thin film of sodium manganese ferrocyanide, Na1.32Mn[Fe(CN)6]0.83·3.

Control of the alkali cation alignment in Prussian blue framework.

We found that the alignments of the alkali cations can be controlled by a distortion of Prussian blue framework; the rubidium ions form a rod structure in a distorted framework of Rb(0.85)Cu[Fe(CN)(6)](0.95)·1.