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Ta3Pb is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ta is bonded in a distorted square co-planar geometry to four equivalent Pb atoms. All Ta–Pb bond lengths are 3.02 Å. Pb is bonded to twelve equivalent Ta atoms to form a mixture of face and corner-sharing PbTa12 cuboctahedra.
ZrTaRu2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two ZrTaRu2 ribbons oriented in the (1, 0, 0) direction. Zr is bonded in a linear geometry to two equivalent Ru atoms. Both Zr–Ru bond lengths are 2.31 Å. Ta is bonded in a linear geometry to two equivalent Ru atoms. Both Ta–Ru bond lengths are 2.21 Å. Ru is bonded in a linear geometry to one Zr and one Ta atom.
La3Ta(O2Cl)3 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. La is bonded in a 10-coordinate geometry to six equivalent O and four equivalent Cl atoms. There are a spread of La–O bond distances ranging from 2.45–2.70 Å. There are a spread of La–Cl bond distances ranging from 3.05–3.11 Å. Ta is bonded in a distorted pentagonal pyramidal geometry to six equivalent O atoms. All Ta–O bond lengths are 2.01 Å. O is bonded to three equivalent La and one Ta atom to form a mixture of distorted corner and edge-sharing OLa3Ta tetrahedra. Cl is bonded in a see-saw-like geometry to four equivalent La atoms.
TaCoAs crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 5-coordinate geometry to five equivalent As atoms. There are a spread of Ta–As bond distances ranging from 2.66–2.70 Å. Co is bonded in a 4-coordinate geometry to four equivalent As atoms. There are a spread of Co–As bond distances ranging from 2.33–2.39 Å. As is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Co atoms.
HfTaMo2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two HfTaMo2 ribbons oriented in the (1, 0, 0) direction. Hf is bonded in a linear geometry to two equivalent Mo atoms. Both Hf–Mo bond lengths are 2.41 Å. Ta is bonded in a linear geometry to two equivalent Mo atoms. Both Ta–Mo bond lengths are 2.31 Å. Mo is bonded in a linear geometry to one Hf and one Ta atom.
TaNbW2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two TaNbW2 ribbons oriented in the (1, 0, 0) direction. Ta is bonded in a linear geometry to two equivalent W atoms. Both Ta–W bond lengths are 2.35 Å. Nb is bonded in a linear geometry to two equivalent W atoms. Both Nb–W bond lengths are 2.28 Å. W is bonded in a linear geometry to one Ta and one Nb atom.
TaVP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 5-coordinate geometry to five equivalent P atoms. There are a spread of Ta–P bond distances ranging from 2.58–2.79 Å. V is bonded in a 4-coordinate geometry to four equivalent P atoms. There are a spread of V–P bond distances ranging from 2.37–2.49 Å. P is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent V atoms.
TaRu2Ge crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two TaRu2Ge ribbons oriented in the (1, 0, 0) direction. Ta is bonded in a linear geometry to two equivalent Ru atoms. Both Ta–Ru bond lengths are 2.18 Å. Ru is bonded in a linear geometry to one Ta and one Ge atom. The Ru–Ge bond length is 2.37 Å. Ge is bonded in a linear geometry to two equivalent Ru atoms.
TaMoRe2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two TaMoRe2 ribbons oriented in the (1, 0, 0) direction. Ta is bonded in a linear geometry to two equivalent Re atoms. Both Ta–Re bond lengths are 2.39 Å. Mo is bonded in a linear geometry to two equivalent Re atoms. Both Mo–Re bond lengths are 2.33 Å. Re is bonded in a linear geometry to one Ta and one Mo atom.
The development of refractory complex concentrated alloys in the Al–Cr–Mo–Ta–Ti alloy system is reported. Alloys with modified Al and Ta concentrations are designed using CALPHAD tools and produced via arc melting and characterized in both as-cast and annealed forms. Properties of the alloys, nature of the microstructures, and phase transformation behavior are described via X-ray diffraction, microstructural characterization, microhardness, and differential scanning calorimetry. Two alloys, namely, Al 0.25 CrMoTa 0.8 Ti and Al 0.75 CrMoTa 0.8 Ti, are represented by a body-centered-cubic matrix phase after annealing, along with a secondary Cr–Ta Laves phase of the C15 and C14 polytypes, respectively. In as-cast and annealed forms, the Al 0.75 CrMoTa 0.45 Ti alloy comprises a single-bcc phase. Microhardness of the Laves phase containing alloys demonstrates susceptibility to cracking, whereas the Al 0.75 CrMoTa 0.45 Ti alloy displays high specific hardness, signs of ductility as evidenced by slip traces near indentations, and minimal scatter of hardness values.
Metal halide perovskite quantum dots (Pe-QDs) are of great interest in new-generation photovoltaics (PVs). However, it remains challenging in the construction of conductive and intact Pe-QD films to maximize their functionality. Herein, a ligand-assisted surface matrix strategy to engineer the surface and packing states of Pe-QD solids is demonstrated by a mild thermal annealing treatment after ligand exchange processing (referred to as “LE-TA”) triggered by guanidinium thiocyanate. The “LE-TA” method induces the formation of surface matrix on CsPbI 3 QDs, which is dominated by the cationic guanidinium (GA+) rather than the SCN-, maintaining the intact cubic structure and facilitating interparticle electrical interaction of QD solids. Consequently, the GA-matrix-confined CsPbI 3 QDs exhibit remarkably enhanced charge mobility and carrier diffusion length compared to control ones, leading to a champion power conversion efficiency of 15.21% when assembled in PVs, which is one of the highest among all Pe-QD solar cells. Additionally, the “LE-TA” method shows similar effects when applied to other Pe-QD PV systems like CsPbBr 3 and FAPbI 3 (FA = formamidinium), indicating its versatility in regulating the surfaces of various Pe-QDs. This work may afford new guidelines to construct electrically conductive and structurally intact Pe-QD solids for efficient optoelectronic devices.
A critical bottleneck for further efficiency breakthroughs in organic solar cells (OSCs) is to minimize the non-radiative energy loss (eΔV nr ) while maximizing the charge generation. With the development of highly emissive low-bandgap non-fullerene acceptors, the design of high-performance donors becomes critical to enable the blend with the electroluminescence quantum efficiency to approach or surpass the pristine acceptor. Herein, by shortening the end-capped alkyl chains of the small-molecular donors from hexyl (MPhS-C6) to ethyl (MPhS-C2), the material obtained aggregation that was insensitive to thermal annealing (TA) along with condensed packing simultaneously. The former leads to small phase separation and suppressed upshifts of the highest occupied molecular orbital energy level during TA, and the latter facilitates its efficient charge-transport at aggregation-less packing. Hence, the ΔV nr decreases from 0.242 to 0.182 V, from MPhS-C6 to MPhS-C2 based OSCs. An excellent PCE of 17.11% is obtained by 1,8-diiodoctane addition due to almost unchanged high J sc (26.6 mA cm –2 ) and V oc (0.888 V) with improved fill factor, which is the record efficiency with the smallest energy loss (0.497 eV) and ΔV nr (0.192 V) in all-small-molecule OSCs. Finally, these results emphasize the potential material design direction of obtaining concurrent TA-insensitive aggregation and condensed packing to maximize the device performances with a super low ΔV nr .
Long-lived carrier population and spin-based behavior in lead halide perovskite nanocrystals (NCs) are very interesting for implementing photovoltaic devices with efficiencies exceeding the Shockley–Queisser limit and quantum information processing, respectively. However, a comprehensive understanding of polaron-mediated charge carrier interactions and an accurate description of the spin-polarized states for spintronics are still lacking. Herein, the carrier and spin interactions are studied under controlled conditions in FAPbI 3 and Cs 0.01 FA 0.99 Pb(Br 0.11 I 0.89 ) 3 NCs through ultrafast transient absorption (TA) spectroscopy. At early timescales, TA spectrum shows an asymmetric derivative feature originating from the hot carrier-induced spectral redshift in FAPbI 3 NCs (55 ± 3 meV) and Cs0.01FA0.99Pb(Br0.11I0.89)3 NCs (54 ± 2 meV) at the bandedges that stabilizes to 9 ± 1 and 11 ± 2 meV, respectively, at 1 ps due to the polaron formation. The kinetic analysis indicates that the polaron populations in FAPbI3 and Cs 0.01 FA 0.99 Pb(Br 0.11 I 0.89 ) 3 NCs decay with an average lifetime of 657 ± 34 and 532 ± 28 ps, respectively. The circular polarization-resolved TA reveals that polaron formation can control spin relaxation in NCs, thus providing a powerful tool to explore the development of their prospective applications in spintronics.
Abstract The novel electrophilic organo‐tantalum catalyst AlS/TaNp x ( 1 ) (Np=neopentyl) is prepared by chemisorption of the alkylidene Np 3 Ta=CH t Bu onto highly Brønsted acidic sulfated alumina (AlS). The proposed catalyst structure is supported by EXAFS, XANES, ICP, DRIFTS, elemental analysis, and SSNMR measurements and is in good agreement with DFT analysis. Catalyst 1 is highly effective for the hydrogenolysis of diverse linear and branched hydrocarbons, ranging from C2 to polyolefins. To the best of our knowledge, 1 exhibits one of the highest polyolefin hydrogenolysis activities (9,800 (CH 2 units) ⋅ mol(Ta) −1 ⋅ h −1 at 200 °C/17 atm H 2 ) reported to date in the peer‐reviewed literature. Unlike the AlS/ZrNp 2 analog, the Ta catalyst is more thermally stable and offers multiple potential C−C bond activation pathways. For hydrogenolysis, AlS/TaNp x is effective for a wide variety of pre‐ and post‐consumer polyolefin plastics and is not significantly deactivated by standard polyolefin additives at typical industrial concentrations.
The novel electrophilic organo-tantalum catalyst AlS/TaNp x (1) (Np=neopentyl) is prepared by chemisorption of the alkylidene Np 3 Ta=CH t Bu onto highly Brønsted acidic sulfated alumina (AlS). Here, the proposed catalyst structure is supported by EXAFS, XANES, ICP, DRIFTS, elemental analysis, and SSNMR measurements and is in good agreement with DFT analysis. Catalyst 1 is highly effective for the hydrogenolysis of diverse linear and branched hydrocarbons, ranging from C2 to polyolefins. To the best of our knowledge, 1 exhibits one of the highest polyolefin hydrogenolysis activities (9,800 (CH 2 units) ⋅ mol(Ta) −1 ⋅ h −1 at 200 °C/17 atm H 2 ) reported to date in the peer-reviewed literature. Unlike the AlS/ZrNp 2 analog, the Ta catalyst is more thermally stable and offers multiple potential C−C bond activation pathways. For hydrogenolysis, AlS/TaNp x is effective for a wide variety of pre- and post-consumer polyolefin plastics and is not significantly deactivated by standard polyolefin additives at typical industrial concentrations.
Abstract BACKGROUND Great efforts have been made to improve the oral bioaccessibility of lipophilic ingredients with multi‐functionalities. Achieving intestinal delivery of lipophilic ingredients and their encapsulation in micelles composed of bile salts and lipid hydrolysates (i.e. fatty acids) is critical for improving oral bioaccessibility. Therefore, oil‐core microcapsules are considered ideal carriers of lipophilic ingredients. Previous studies have reported oil‐core/zein‐shell microcapsules constructed by a one‐step anti‐solvent process. Still, its efficacy as an intestinal delivery system was limited because if the porous shell structure. RESULTS Zein solution was pretreated with ultrasound and tannic acid (TA) cross‐linking. Composite oil‐core microcapsule (COM) with a compact shell structure was successfully prepared by using modified zein solution in the anti‐solvent process. Fourier‐transform infrared spectroscopy and circular dichroism analyses indicated that ultrasound and TA synergistically promote the conformational transition of zein from α‐helix to β‐sheet and enhance the hydrophobic interactions among protein chains. The above changes contribute to the strengthen of shell zein network. Correspondingly, COM presents superior encapsulation efficiency and environmental stability over the simple oil‐core microcapsule (SOM) prepared without the use of ultrasound and TA. Furthermore, antioxidant activity of β‐carotene was well retained during the encapsulation process. In vitro studies indicated that COM was more resistant to digestibility and acid‐induced swelling. More than 87% of β‐carotene could be released in the intestine in a sustainable way. The controllable release behavior thus promoted a significant increase in bioaccessibility of β‐carotene encapsulated in COM compared to SOM (85.9% versus 48.5%). CONCLUSION The COM generated here shows potential for bioaccessibility improvement of lipophilic ingredients. © 2022 Society of Chemical Industry.
Understanding band alignment and charge transfer at complex oxide interfaces is critical to tailoring and utilizing their diverse functionality. Toward this goal, both Ohmic- and Schottky-like charge transfers at oxide/oxide semiconductor/metal interfaces are designed and experimentally validated. A method for predicting band alignment and charge transfer in ABO 3 perovskites is utilized, where previously established rules for simple semiconductors fail. The prototypical systems chosen are the rare class of oxide metals, SrBO 3 with B = V–Ta, when interfaced with the multifaceted semiconducting oxide, SrTiO 3 . For B = Nb and Ta, it is confirmed that a large accumulation of charge occurs in SrTiO 3 due to the higher energy Nb and Ta states relative to Ti. Furthermore, this gives rise to a high mobility metallic interface, which is an ideal epitaxial oxide/oxide Ohmic contact. On the contrary, for B = V, there is no charge transfer into the SrTiO 3 interface, which serves as a highly conductive epitaxial gate metal. Going beyond these specific cases, this work opens the door to integrating the vast phenomena of ABO 3 perovskites into a wide range of practical devices.
Batch equilibrium experiments were performed to determine the distribution coefficients for Sc, Ir, and Ta on N,N,N’,N’tetraoctyl-1,5-diglycolamide (TODGA) resin in various acid matrices. Distribution coefficients were determined in hydrochloric acid (Sc, Ir), nitric acid (Sc, Ta), and a mixture of nitric acid and 0.2M hydrofluoric acid (Sc, Ir, Ta). The distribution coefficients determined through these experiments were then utilized to create a group separation method for activation products, fission products, and environmental constituents.