B18-Core EXAFS
|
Diamond Proposal Number(s):
[14239]
Open Access
Abstract: Rechargeable aqueous batteries are promising devices for large-scale energy storage applications because of their low-cost, inherent safety, and environmental friendliness. Among them, aqueous ammonium-ion (NH4+) batteries (AAIB) are currently emerging owing to the fast diffusion kinetics of NH4+. Nevertheless, it is still a challenge to obtain stable AAIB with relatively high output potential, considering the instability of many electrode materials in an aqueous environment. Herein, we report a cell based on a concentrated (5.8m) aqueous (NH4)2SO4 electrolyte, ammonium copper hexacyanoferrate (N-CuHCF) as the positiveelectrode (cathode), and 3,4,9,10-Perylene-bis(dicarboximide) (PTCDI) as the negative electrode (anode). The solvation structure, electrochemical properties, as well as the electrode-electrolyte interface and interphase are systematically investigated by the combination of theoretical and experimental methods. The results indicate for a remarkable cyling performance of the low-cost rocking-chair AAIB, which offers a capacity retention of around 72% after 1000 cycles and an average output potential of around 1.0 V.
|
Jun 2022
|
|
E02-JEM ARM 300CF
I14-Hard X-ray Nanoprobe
|
Diamond Proposal Number(s):
[25250, 20420]
Abstract: The interaction of high-energy electrons and X-ray photons with beam-sensitive semiconductors such as halide perovskites is essential for the characterisation and understanding of these optoelectronic materials. Using nano-probe diffraction techniques, which can investigate physical properties on the nanoscale, we perform studies of the interaction of electron and X-ray radiation with state-of-the-art (FA0.79MA0.16Cs0.05)Pb(I0.83Br0.17)3 hybrid halide perovskite films (FA, formamidinium; MA, methylammonium). We track the changes in the local crystal structure as a function of fluence using scanning electron diffraction and synchrotron nano X-ray diffraction techniques. We identify perovskite grains from which additional reflections, corresponding to PbBr2, appear as a crystalline degradation phase after fluences of ∼200 e–Å–2. These changes are concomitant with the formation of small PbI2 crystallites at the adjacent high-angle grain boundaries, with the formation of pinholes, and with a phase transition from tetragonal to cubic. A similar degradation pathway is caused by photon irradiation in nano-X-ray diffraction, suggesting common underlying mechanisms. Our approach explores the radiation limits of these materials and provides a description of the degradation pathways on the nanoscale. Addressing high-angle grain boundaries will be critical for the further improvement of halide polycrystalline film stability, especially for applications vulnerable to high-energy radiation such as space photovoltaics.
|
Mar 2022
|
|
I11-High Resolution Powder Diffraction
|
Dingyue
Hu
,
Karl
Dawson
,
Marco
Zanella
,
Troy D.
Manning
,
Luke M.
Daniels
,
Nigel D.
Browning
,
B. Layla
Mehdi
,
Yaobin
Xu
,
Houari
Amari
,
J. Felix
Shin
,
Michael J.
Pitcher
,
Ruiyong
Chen
,
Hongjun
Niu
,
Bowen
Liu
,
Matthew
Bilton
,
Junyoung
Kim
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[23666]
Open Access
Abstract: Performance durability is one of the essential requirements for solid oxide fuel cell materials operating in the intermediate temperature range (500–700 °C). The trade-off between desirable catalytic activity and long-term stability challenges the development and commercialization of electrode materials. Here an oxygen cathode material, Ba0.5Sr0.5(Co0.7Fe0.3)0.69−xMgxW0.31O3−δ (BSCFW-xMg), that exhibits excellent electrocatalytic performance through the addition of an optimized amount of Mg to the self-assembled nanocomposite Ba0.5Sr0.5(Co0.7Fe0.3)0.69W0.31O3−δ (BSCFW) by simple solid-state reaction is reported. Distinct from the bulk and surface approaches to introduce vacancies and defects in materials design, here the Mg2+ ions concentrate at the single perovskite/double perovskite interface of BSCFW with dislocations and Mg2+-rich nanolayers, resulting in stressed and compositionally inhomogeneous interface regions. The interfacial chemistry within these nanocomposites provides an additional degree of freedom to enable performance optimization over single phase materials and promotes the durability of alkaline-earth based fuel cell materials.
|
Mar 2022
|
|
I22-Small angle scattering & Diffraction
|
Diamond Proposal Number(s):
[23642, 18658]
Open Access
Abstract: Lipid nanoparticles (LNPs) are versatile structures with tunable physicochemical properties that are ideally suited as a platform for vaccine delivery and RNA therapeutics. A key barrier to LNP rational design is the inability to relate composition and structure to intracellular processing and function. Here we combine Single Particle Automated Raman Trapping Analysis (SPARTA®) with small angle scattering (SAXS / SANS) techniques to link LNP composition with internal structure and morphology and to monitor dynamic LNP - phospholipase D (PLD) interactions. Our analysis demonstrates that phospholipase D, a key intracellular trafficking mediator, can access the entire LNP lipid membrane to generate stable, anionic LNPs. PLD activity on vesicles with matched amounts of enzyme substrate was an order of magnitude lower, indicating that the LNP lipid membrane structure can be used to control enzyme interactions. This represents an opportunity to design enzyme-responsive LNP solutions for stimuli-responsive delivery and diseases where PLD is dysregulated.
|
Mar 2022
|
|
I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Suhan
Son
,
Youjin
Lee
,
Jae Ha
Kim
,
Beom Hyun
Kim
,
Chaebin
Kim
,
Woongki
Na
,
Hwiin
Ju
,
Sudong
Park
,
Abhishek
Nag
,
Ke-Jin
Zhou
,
Young-Woo
Son
,
Hyeongdo
Kim
,
Woo-Suk
Noh
,
Jae-Hoon
Park
,
Jong Seok
Lee
,
Hyeonsik
Cheong
,
Jae Hoon
Kim
,
Je-Geun
Park
Diamond Proposal Number(s):
[29554]
Abstract: Matter-light interaction is at the center of diverse research fields from quantum optics to condensed matter physics, opening new fields like laser physics. A magnetic exciton is one such rare example found in magnetic insulators. However, it is relatively rare to observe that external variables control matter-light interaction. Here, we report that the broken inversion symmetry of multiferroicity can act as an external knob enabling the magnetic exciton in van der Waals antiferromagnet NiI2. We further discover that this magnetic exciton arises from a transition between Zhang-Rice-triplet and Zhang-Rice-singlet's fundamentally quantum entangled states. This quantum entanglement produces an ultra-sharp optical exciton peak at 1.384 eV with a 5 meV linewidth. Our work demonstrates that NiI2 is two-dimensional magnetically ordered with an intrinsically quantum entangled ground state.
|
Dec 2021
|
|
I07-Surface & interface diffraction
|
Diamond Proposal Number(s):
[18570]
Open Access
Abstract: Planar organic heterostructures are widely explored and employed in photovoltaic cells, light-emitting diodes, and bilayer field-effect transistors. An important role for device performance plays the energy level alignment at the inorganic–organic and organic–organic interfaces. In this work, incremental ultraviolet photoelectron spectroscopy measurements and real-time X-ray scattering experiments are used to thoroughly investigate the thickness-dependent electronic and structural properties of a perfluoropentacene (PFP)-on-[6]phenacene heterostructure. For both materials an incremental increase of the material work function (positive interface dipole) is found. For [6]phenacene, this can be assigned to a thickness-dependent change of molecular arrangement evident from a change of the unit cell volume and a consequential alteration of the ionization energy. In the case of PFP the interface dipole stems from charge transfer from the substrate into unoccupied molecular orbitals resulting in an electrostatic potential on the surface. The magnitude of this potential can be correlated with an increased gap state density resulting from templated structural defects mediated by the bottom layer.
|
Dec 2021
|
|
I16-Materials and Magnetism
|
Peter
Finkel
,
Markys G.
Cain
,
Thomas
Mion
,
Margo
Staruch
,
Jakub
Kolacz
,
Sukriti
Mantri
,
Chad
Newkirk
,
Kyril
Kavetsky
,
John
Thornton
,
Junhai
Xia
,
Marc
Currie
,
Thomas
Hase
,
Alex
Moser
,
Paul
Thompson
,
Christopher
Lucas
,
Andy
Fitch
,
Julie M.
Cairney
,
Scott D.
Moss
,
A. Gareth A.
Nisbet
,
John E.
Daniels
,
Samuel E.
Lofland
Diamond Proposal Number(s):
[18924]
Abstract: Electrical switching of ferroelectric domains and subsequent domain wall motion promotes strong piezoelectric activity; however, light scatters at refractive index discontinuities such as those found at domain wall boundaries. Thus, simultaneously achieving large piezoelectric effect and high optical transmissivity is generally deemed infeasible. Here, it is demonstrated that the ferroelectric domains in perovskite Pb(In1/2Nb1/2)O3 Pb(Mg1/3Nb2/3)O3-PbTiO3 domain-engineered crystals can be manipulated by electrical field and mechanical stress to reversibly and repeatably, with small hysteresis, transform the opaque poly-domain structure into a highly transparent mono-domain state. This control of optical properties can be achieved at very low electric fields (less than 1.5 kV cm−1) and is accompanied by a large (>10000 pm V−1) piezoelectric coefficient that is superior to that of linear state-of-the-art materials by a factor of three or more. The coexistence of tunable optical transmissivity and high piezoelectricity paves the way for a new class of photonic devices.
|
Nov 2021
|
|
I09-Surface and Interface Structural Analysis
|
Diamond Proposal Number(s):
[26551]
Open Access
Abstract: For sodium-ion batteries, two pressing issues concerning electrolytes are flammability and compatibility with hard carbon anode materials. Non-flammable electrolytes that are sufficiently stable against hard carbon have—to the authors’ knowledge—previously only been obtained by either the use of high salt concentrations or additives. Herein, the authors present a simple, fluorine-free, and flame-retardant electrolyte which is compatible with hard carbon: 0.38 m sodium bis(oxalato)borate (NaBOB) in triethyl phosphate (TEP). A variety of techniques are employed to characterize the physical properties of the electrolyte, and to evaluate the electrochemical performance in full-cell sodium-ion batteries. The results reveal that the conductivity is sufficient for battery operation, no significant self-discharge occurs, and a satisfactory passivation is enabled by the electrolyte. In fact, a mean discharge capacity of 107 ± 4 mAh g−1 is achieved at the 1005th cycle, using Prussian white cathodes and hard carbon anodes. Hence, the studied electrolyte is a promising candidate for use in sodium-ion batteries.
|
Oct 2021
|
|
I13-1-Coherence
|
Diamond Proposal Number(s):
[25873, 25442]
Abstract: Photothermal interfacial evaporation based on micro-nano porous materials is an effective and energy-saving new strategy to utilize low-density solar energy to achieve water purification, but there are still many challenges especially in preparing nanostructures toward enhanced performances. Here, a one-step simple method is adopted by using nanosecond laser to process the surface of monolithic biomass carbon under ambient conditions. During the preparation process, the surface of biomass carbon is directly converted into patterned porous graphene under the action of nanosecond laser. This method not only provides a new way for the wide and easy preparation of graphene, but more importantly, it can be very convenient to prepare graphene-biomass porous carbon composites with special textures and special microstructures with ultra-broadband light absorption. The combination of the macroscopic porous feature in monolithic carbon revealed by synchrotron X-ray ptychography together with the nanostructured surface of patterned porous graphene demonstrates ultrahigh solar thermal-vapor conversion rate up to 98.7%. This work develops an effective way to fabricate porous graphene from biomass carbon, as well as an energy-efficient water treatment technology toward wastewater containing complex contaminants.
|
Oct 2021
|
|
I07-Surface & interface diffraction
|
Shuai
Yuan
,
Lin-Song
Cui
,
Linjie
Dai
,
Yun
Liu
,
Qing-Weii
Liu
,
Yu-Qi
Sun
,
Florian
Auras
,
Miguel
Anaya
,
Xiaopeng
Zheng
,
Edoardo
Ruggeri
,
You-Jun
Yu
,
Yang-Kun
Qu
,
Mojtaba
Abdi-Jalebi
,
Osman M.
Bakr
,
Zhao-Kui
Wang
,
Samuel D.
Stranks
,
Neil C.
Greenham
,
Liang-Sheng
Liao
,
Richard H.
Friend
Diamond Proposal Number(s):
[17223]
Open Access
Abstract: Metal halide perovskite semiconductors have demonstrated remarkable potentials in solution-processed blue light-emitting diodes (LEDs). However, the unsatisfied efficiency and spectral stability responsible for trap-mediated non-radiative losses and halide phase segregation remain the primary unsolved challenges for blue perovskite LEDs. In this study, it is reported that a fluorene-based π-conjugated cationic polymer can be blended with the perovskite semiconductor to control film formation and optoelectronic properties. As a result, sky-blue and true-blue perovskite LEDs with Commission Internationale de l'Eclairage coordinates of (0.08, 0.22) and (0.12, 0.13) at the record external quantum efficiencies of 11.2% and 8.0% were achieved. In addition, the mixed halide perovskites with the conjugated cationic polymer exhibit excellent spectral stability under external bias. This result illustrates that π-conjugated cationic polymers have a great potential to realize efficient blue mixed-halide perovskite LEDs with stable electroluminescence.
|
Sep 2021
|
|
