A major bottleneck delaying the further commercialization of thin-film solar cells based on hybrid organohalide lead perovskites is interface loss in state-of-the-art devices. We present a generic ...interface architecture that combines solution-processed, reliable, and cost-efficient hole-transporting materials without compromising efficiency, stability, or scalability of perovskite solar cells. Tantalum-doped tungsten oxide (Ta-WOₓ)/conjugated polymer multilayers offer a surprisingly small interface barrier and form quasi-ohmic contacts universally with various scalable conjugated polymers. In a simple device with regular planar architecture and a self-assembled monolayer, Ta-WOₓ–doped interface–based perovskite solar cells achieve maximum efficiencies of 21.2% and offer more than 1000 hours of light stability. By eliminating additional ionic dopants, these findings open up the entire class of organics as scalable hole-transporting materials for perovskite solar cells.
Cocatalysts have been extensively used to promote water oxidation efficiency in solar‐to‐chemical energy conversion, but the influence of interface compatibility between semiconductor and cocatalyst ...has been rarely addressed. Here we demonstrate a feasible strategy of interface wettability modification to enhance water oxidation efficiency of the state‐of‐the‐art CoOx/Ta3N5 system. When the hydrophobic feature of a Ta3N5 semiconductor was modulated to a hydrophilic one by in situ or ex situ surface coating with a magnesia nanolayer (2–5 nm), the interfacial contact between the hydrophilic CoOx cocatalyst and the modified hydrophilic Ta3N5 semiconductor was greatly improved. Consequently, the visible‐light‐driven photocatalytic oxygen evolution rate of the resulting CoOx/MgO(in)–Ta3N5 photocatalyst is ca. 23 times that of the pristine Ta3N5 sample, with a new record (11.3 %) of apparent quantum efficiency (AQE) under 500–600 nm illumination.
Hydrophilic interface modification of a CoOx‐modified Ta3N5 photocatalyst with a magnesia nanolayer significantly improves its water oxidation efficiency under visible light irradiation. The essential roles of the interface modification are proposed to enhance the interfacial coverage of the CoOx/Ta3N5 photocatalyst and to decrease the defect density of Ta3N5 semiconductor. AQE=apparent quantum efficiency.
Atom‐economic and regioselective Csp3
−Csp3
bond formation has been achieved by rapid C−H alkylation of unprotected secondary arylamines with unactivated alkenes. The combination of Ta(CH2SiMe3)3Cl2, ...and a ureate N,O‐chelating‐ligand salt gives catalytic systems prepared in situ that can realize high yields of β‐alkylated aniline derivatives from either terminal or internal alkene substrates. These new catalyst systems realize C−H alkylation in as little as one hour and for the first time a 1:1 stoichiometry of alkene and amine substrates results in high yielding syntheses of isolated amine products by simple filtration and concentration.
Speed by design: Atom‐economic and regioselective Csp3
−Csp3
bond formation has been achieved by rapid C−H alkylation of unprotected secondary arylamines with unactivated alkenes. The combination of Ta(CH2SiMe3)3Cl2 and a ureate N,O‐chelating‐ligand salt provides high yields of β‐alkylated aniline derivatives.
This study provides scenarios toward 2050 for the demand of five metals in electricity production, cars, and electronic appliances. The metals considered are copper, tantalum, neodymium, cobalt, and ...lithium. The study shows how highly technology-specific data on products and material flows can be used in integrated assessment models to assess global resource and metal demand. We use the Shared Socio-economic Pathways as implemented by the IMAGE integrated assessment model as a starting point. This allows us to translate information on the use of electronic appliances, cars, and renewable energy technologies into quantitative data on metal flows, through application of metal content estimates in combination with a dynamic stock model. Results show that total demand for copper, neodymium, and tantalum might increase by a factor of roughly 2 to 3.2, mostly as a result of population and GDP growth. The demand for lithium and cobalt is expected to increase much more, by a factor 10 to more than 20, as a result of future (hybrid) electric car purchases. This means that not just demographics, but also climate policies can strongly increase metal demand. This shows the importance of studying the issues of climate change and resource depletion together, in one modeling framework.
The room‐temperature reaction of Cp*TaCl4 with LiBH4⋅THF followed by addition of S2CPPh3 results in pentahydridodiborate species (Cp*Ta)2(μ,η2:η2‐B2H5)(μ‐H)(κ2,μ‐S2CH2)2 (1), a classical B2H5− ion ...stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of B2H5− in 1 is mainly due to the stabilization of sp2‐B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)4} fragment (M=Mo or W) resulted in simple adducts, {(Cp*Ta)(CH2S2)}2(B2H5)(H){M(CO)3} (6: M=Mo and 7: M=W), that retained the diborane(5) unit.
Isolation of a classical diborane(5) complex of tantalum was achieved by the room‐temperature reaction of Cp*TaCl4 with LiBH4⋅THF followed by addition of S2CPPh3. Reactivity with metal carbonyls was also explored.
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High-strength fully porous biomaterials built with additive manufacturing provide an exciting opportunity for load-bearing orthopedic applications. While factors controlling their ...mechanical and biological response have recently been the subject of intense research, the interplay between mechanical properties, bone ingrowth requirements, and manufacturing constraints, is still unclear. In this paper, we present two high-strength stretch-dominated topologies, the Tetrahedron and the Octet truss, as well as an intuitive visualization method to understand the relationship of cell topology, pore size, porosity with constraints imposed by bone ingrowth requirements and additive manufacturing. 40 samples of selected porosities are fabricated using Selective Laser Melting (SLM), and their morphological deviations resulting from SLM are assessed via micro-CT. Mechanical compression testing is used to obtain stiffness and strength properties, whereas bone ingrowth is assessed in a canine in vivo model at four and eight weeks. The results show that the maximum strength and stiffness ranged from 227.86±10.15 to 31.37±2.19MPa and 4.58±0.18 to 1.23±0.40GPa respectively, and the maximum 0.2% offset strength is almost 5 times stronger than that of tantalum foam. For Tetrahedron samples, bone ingrowth after four and eight weeks is 28.6%±11.6%, and 41.3%±4.3%, while for the Octet truss 35.5%±1.9% and 56.9%±4.0% respectively. This research is the first to demonstrate the occurrence of bone ingrowth into high-strength porous biomaterials which have higher structural efficiency than current porous biomaterials in the market.
We present two stretch-dominated cell topologies for porous biomaterials that can be used for load-bearing orthopaedic applications, and prove that they encourage bone ingrowth in a canine model. We also introduce an intuitive method to visualize and understand the relationship of cell topology, pore size, porosity with constraints imposed by bone ingrowth requirements and additive manufacturing. We show this strategy helps to gain insight into the interaction of exogenous implant factors and endogenous system factors that can affect the success of load-bearing orthopaedic devices.
Surface modulation via injection or extraction of charge carriers in microelectric devices has been used to tune the energy band alignment for desired electrical and optical properties, yet not well ...recognized in photocatalysis field. Here, taking semiconductor bismuth tantalum oxyhalides (Bi4TaO8X) as examples, chemically inactive molybdenum oxide (MoO3) with a large work function is introduced to qualitatively tune the properties of interfacial charges, achieving an evidently enhanced upward band bending and intensive built‐in electric field. Such a simple charge modulation exhibits a remarkable improvement in photocatalytic water oxidation, reaching an apparent quantum efficiency of 25% at the input wavelength of 420 nm. The validity and generality of surface charge modulating strategy are further demonstrated using other semiconductors (e.g., C3N4) and decorators (e.g., V2O5). The findings not only provide a promising strategy for rationally manipulating the interfacial built‐in electric field in photocatalysis but also pave the way to learn from microelectronic technologies to construct artificial photosynthesis systems for solar energy conversion.
Molybdenum oxide (MoO3) is introduced as a surface modification on Bi4TaO8X (X = Cl, Br) to tune the interfacial charges, achieving an enhanced upward band bending as well as an intensive built‐in electric field. Such charge modulation results in an evident improvement in photocatalytic water oxidation under visible light irradiation, reaching an apparent quantum efficiency of 25% at 420 nm.
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