CoreTech (China)

The buried interface tens of nanometers beneath the solid-liquid junction is crucial for photocarrier extraction, influencing the overall efficiency of photoelectrochemical devices. Precise characterization of the interfacial properties is essential for device optimization but remains challenging. Here, we directly probe the in situ transformation of a CuxO interlayer at the NiO/n-Si interface by hard X-ray photoelectron spectroscopy. It is found that Cu(I) in the CuxO interlayer gradually transforms to Cu(II) with air exposure, forming an energetically more favorable interface and improving photoanode’s efficiency. Based on this finding, a reactive e-beam evaporation process is developed for the direct deposition of a CuO interlayer, achieving a half-cell solar-to-hydrogen efficiency of 4.56% for the optimized NiO/CuO/n-Si heterojunction photoanode. Our results highlight the importance of precision characterization of interfacial properties with advanced hard X-ray photoelectron spectroscopy in guiding the design of efficient solar water-splitting devices.

Crystallization modulation and defect passivation are key for high performance perovskite solar cells (PSCs) through suppressing defects in the surface and/or near the grain boundaries (GBs) of solution-processed perovskite films.

Herein, hollow sulfur spheres encapsulated hermetically by FePS3 flakes (HSS@FePS3) are utilized in lithium sulfur batteries (LSBs). Via the encapsulation, soluble polysulfide can be trapped obviously and volume expansion during discharge can be accommodated effectively. The HSS@FePS3 cathode shows an excellent cycling stability even at a current density of 1C (a capacity decay of 0.0461% per cycle during 1000 cycles).

Black phosphorus (BP) is a desirable anode material for alkali metal ion storage owing to its high electronic/ionic conductivity and theoretical capacity. In-depth understanding of the redox reactions between BP and the alkali metal ions is key to reveal the potential and limitations of BP, and thus to guide the design of BP-based composites for high-performance alkali metal ion batteries. Comparative studies of the electrochemical reactions of Li+ , Na+ , and K+ with BP were performed. Ex situ X-ray absorption near-edge spectroscopy combined with theoretical calculation reveal the lowest utilization of BP for K+ storage than for Na+ and Li+ , which is ascribed to the highest formation energy and the lowest ion diffusion coefficient of the final potassiation product K3 P, compared with Li3 P and Na3 P. As a result, restricting the formation of K3 P by limiting the discharge voltage achieves a gravimetric capacity of 1300 mAh g-1 which retains at 600 mAh g-1 after 50 cycles at 0.25 A g-1 .

Mesh generation is one of the key factors affecting computational efficiency and accuracy in finite element analysis.More and more software provides modules for automatic meshes generation. Owing to the complexity and variety of the shape on a CAD model, it needs the recognition of specific features to enhance the success of meshes generation. Holes are one of the fundamental features in 3D CAD models and appear in various types of form. The aim of this study is to present a method for the recognition of different kinds of holes. The primary concept of the proposed algorithm is to detect blend faces first, and then search for holes in accordance with the loop data in the B-rep model. The procedures for the recognition of blend faces and holes are described. Several examples are also presented to demonstrate the feasibility of the proposed algorithm.

Quasi-biclique mining for bipartite graphs has found important applications in providing security services. However, the standard MapReduce algorithm for mining quasi-bicliques does not scale well due to the need of shuffling and reducing a huge number of map outputs. To cope with web-scale graphs, we propose a scalable algorithm with the use of Giraph, which is a new rising large-scale graph processing platform following the bulk synchronous parallel (BSP) model. Experimental results on real world domain-IP graphs demonstrate that our proposed solution is able to reduce CPU time by 80% and disk I/O by 95%, compared with the standard MapReduce algorithm.