Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Enantioselective synthesis. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Silver Nanowire Percolation Network Soldered with Graphene Oxide at Room Temperature and Its Application for Fully Stretchable Polymer Light-Emitting Diodes

Abstract: Transparent conductive electrodes with high surface conductivity, high transmittance in the visible wavelength range, and mechanical compliance are one of the major challenges in the fabrication of stretchable optoelectronic devices. We report the preparation of a transparent conductive electrode (TCE) based on a silver nanowire (AgNW) percolation network modified with graphene oxide (GO). The monatomic thickness, mechanical flexibility, and strong bonding with AgNWs enable the GO sheets to wrap around and solder the AgNW junctions and thus dramatically reduce the inter-nanowire contact resistance without heat treatment or high force pressing. The GO-soldered AgNW network has a figure-of-merit sheet resistance of 14 ohm/sq with 88% transmittance at 550 nm. Its storage stability is improved compared to a conventional high-temperature annealed AgNW network. The GO-soldered AgNW network on polyethylene terephthalate films was processed from solutions using a drawdown machine at room temperature. When bent to...

Azido-mediated systems showing different magnetic behaviors

Abstract: Azido has been one of the well used bridging ligands in the construction of magnetic molecule materials, which has stimulated considerable interest in magnetochemistry. This tutorial review is concentrated on the study of azido metal compounds with their magnetochemistry and consists of eight main sections. The first section offers an introduction to azido complexes and some important results obtained from magneto–structural correlation in azido complexes which will be referred to in the following sections. The next six sections give overviews of azido-mediated ferromagnets, ferrimagnets, canted (weak) ferromagnets, antiferromagnets, single molecule magnets (SMMs) and single chain magnets (SCMs), and metamagnets. The last section is the conclusion and gives a perspective of azido-mediated magnets.

Room-temperature ferromagnetism of graphene.

Abstract: Aiming at molecular-based magnets, ferromagnetism of pure carbon-based materials is fundamentally and technologically extremely important for many applications. While it is still not fully understood, many recent theoretical works have suggested that one-atom-thick two-dimensional graphene materials may show ferromagnetism due to the existence of various defects or topological structures as the spin units and the possible long-range ordered coupling among them. Here, we report the experimental results on the ferromagnetism of graphene-based materials at room temperature. The observed room-temperature ferromagnetism is believed to come from the defects on graphene.

Design and synthesis of 3d-4f metal-based zeolite-type materials with a 3D nanotubular structure encapsulated "water" pipe.

Abstract: A nanotubular 3D heterometallic zeolitic polymer, {[Yb(PDA)3Mn1.5(H2O)3]·1.5H2O}n (2), was designed and synthesized by simply tuning the amount of coordinated water on the Mn ion in the molecular ladder polymer {[Yb(PDA)3Mn1.5(H2O)6]·6H2O}n (1). 1 and 2 were structurally and magnetically characterized. The water molecules capsulated within the nanotube were arrayed into an unprecedented “water” pipe. The robust 2 retained intact networks after the removal of guest water trapped in the nanotubes and even after methanol replaced guest water.

Carbon Nanotubes with Titanium Nitride as a Low‐Cost Counter‐Electrode Material for Dye‐Sensitized Solar Cells

Abstract: Dye-sensitized solar cells (DSSCs) are promising candidates for low-cost and clean energy conversion devices. In the development of DSSCs, key challenges include the demonstration of high efficiency and scale-up of fabrication. As the conventional counter-electrode material in the devices, platinum, is a burden for large-scale applications of DSSCs because it is one of the most expensive materials available. Furthermore, the sustaining improvement of semiconductor electrode and electrolyte poses higher demand on counterelectrode performance. Therefore, it is necessary to develop low-cost and platinum-free counter-electrode materials with relatively high conversion efficiency for DSSCs. The counter electrode in DSSCs promotes the electron translocation from the external circuit back to the redox electrolyte, and catalyzes the reduction of triiodide ions. Therefore, counter-electrode materials of high electrical conductivity and superior electrocatalytic activity are highly desired. 7] However, it is usually not easy to meet the both above requirements simultaneously. Generally, small particles provide high electrocatalytic activity owing to the large surface area, but they also lower electron transport efficiency owing to the abundant grain boundaries and defects. According to previous studies, carbonaceous materials, such as carbon nanotubes (CNTs), 10] carbon black, mesoporous carbon, activated carbon, fullerene, and electroconductive polymers, 15] generally show good performance because the large surface area of the materials can redress the low intrinsic electrocatalytic activity of carbon. Gr tzel and co-workers recently deposited electrochemically CoS nanoparticles on PEN/ITO film with good electrical conductivity to obtain a high-performance platinum-free counter electrode with a remarkable cell stability. To combine both high electrical conductivity and superior electrocatalytic activity in one material, we propose an alternative design for the fabrication of low-cost and platinum-free counter-electrode materials by constructing a fast electron-transport network and creating highly active sites on the electron pathway. Multi-walled carbon nanotubes can be considered as a fast electron-transport network because of the coexistence of ballistic and diffusive transport and the tubular morphology. Furthermore, CNTs possess electrocatalytic activity for the reduction of triiodide ions to a certain extent, and their good mechanical properties are also helpful for the formation of electrode film. Therefore, CNTs are suitable matrix material for constructing a fast electron-transport network. Regarding the highly efficient electrocatalyst, titanium nitrides (TiN) demonstrate high intrinsic electrocatalytic activity for the reduction of triiodide ions owing to the similarity of the electronic structure of the metal nitrides to that of the noble metals. 20] A DSSC composed of the highly ordered TiN nanotube arrays shows comparable performance with typical Pt counter electrode. However, TiN nanoparticle film electrode alone has lower fill factor (FF) owing to the poor electron transport efficiency across nanoparticles. Furthermore, the introduction of conducting paths of CNTs into TiN can improve electrical conductivity and capacitance of TiN. Herein, we demonstrate that low-cost TiN-CNTs, fabricated by anchoring TiN nanoparticles on the CNTs network, can provide simultaneous high electrical conductivity and superior electrocatalytic activity. TiN-CNTs were prepared by thermal hydrolysis of TiOSO4 on CNTs and subsequent nitridation in an ammonia atmosphere. XRD results indicate that the as-prepared sample consists of cubic TiN (JCPDS 87-0633) and carbon nanotubes. No peaks of other titanium species are observed in the XRD pattern (Supporting Information, Figure S1). Structural details of TiN-CNTs were investigated using TEM and STEM with EDS. TiN nanoparticles, with a size of less than 10 nm, are dispersedly loaded on the surface of CNTs (Figure 1a), whilst no TiN aggregates are observed because of the slow hydrolysis of TiOSO4, with a low concentration under the moderate conditions. A HRTEM image (Figure 1b) confirms that TiN nanoparticles have a relatively high crystallinity and an average size of 5–10 nm. Furthermore, the walls of CNTs are locally distorted near TiN nanoparticles, indicating a strong interaction between TiN nanoparticles and CNTs, which possibly originates from the hydrolysis reaction between hydroxy groups on CNTs and the titanium salt used in the preparation process. The strong interaction causes the TiN nanoparticles to be tightly loaded on CNTs, and electron transport between TiN and CNTs occurs easily. The element distribution of TiN-CNTs is investigated by EDS line-scanning. In the STEM image (Figure 1c), TiN nanoparticles show a white contrast owing to the high atomic number of titanium compared to carbon. EDS linescanning, taken across a single carbon nanotube in Figure 1c from right to left, is shown in Figure 1d. Qualitatively, a [*] Dr. G. R. Li, F. Wang, Dr. Q. W. Jiang, Prof. X. P. Gao, Prof. P. W. Shen Institute of New Energy Material Chemistry Tianjin Key Laboratory of Metaland Molecule-Based Material Chemistry Nankai University, Tianjin 300071 (China) Fax: (+ 86)22-2350-0876 E-mail: xpgao@nankai.edu.cn