Fazhu Ding

Removal of CdTe in acidic media by magnetic ion-exchange resin: a potential recycling methodology for cadmium telluride photovoltaic waste.

Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

Highly (00l)-oriented Bi2Te3/Te heterostructure thin film with enhanced power factor

Introducing nanoscale heterostructure interfaces into material matrix is an effective strategy to optimize the thermoelectric performance by energy-dependent carrier filtering effect. In this study, highly (00l)-oriented Bi2Te3/Te heterostructure thin films have been fabricated on single-crystal MgO substrates using a facile magnetron co-sputtering method. Bi2Te3/Te heterostructure thin films with Te contents of 63.8 at% show an optimized thermoelectric performance, which possess a Seebeck coefficient of -157.7 μV K-1 and an electrical conductivity of 9.72 × 104 S m-1, leading to a high power factor approaching 25 μW cm-1 K-2. The partially decoupled behavior of the Seebeck coefficient and electrical conductivity is contributed to Bi2Te3/Te heterostructure interfaces, which causes interfacial barrier filtering and scattering effects; thus, a high level of the Seebeck coefficient is obtained. Meanwhile, carrier transport in a-b plane can benefit from the highly preferred orientation, which guarantees a remarkably high electrical conductivity. We anticipate that our strategy may guide the way for preparing high-performance thermoelectric materials by microstructure design and regulation.

Epitaxial growth of CaTiO3 buffer layer for fabrication of c-axis oriented YBCO film by sol-gel method

The CaTiO3 (CTO) films were epitaxially grown on (00l)-oriented LaAlO3 (LAO) single-crystal substrates by sol-gel method. The final CTO film shows a good biaxial texture, especially with a very small full width at half maximum value of ϕ- scans of about 0.32°. The epitaxial relationship between CTO film and LAO substrate are CTO [110] // LAO [100] and CTO [001] // LAO [001], respectively. The CTO film also exhibits a compact and smooth surface with a root mean square roughness of about 6.8 nm. Moreover, the microstructure and superconducting properties of the YBa2Cu3O7-δ (YBCO) thin film deposited on the CTO/LAO bilayer structure was investigated. The YBCO film is highly c-axis oriented. The high critical current density (JC) value of about 3.7 MA/cm2 was obtained at 77 K in self-field, suggesting that the CTO thin film is a very promising candidate for buffer layer in YBCO coated conductors.Graphical Abstract

Synthesis, characterization and thermostability of barium β-diketonate with tetraethylenepentamine ligand

The metal-organic chemical vapor deposition (MOCVD) technique is a promising process for high-temperature superconductor YBa2Cu3O7−δ(YBCO) preparation. In this technique, it is a challenge to obtain barium precursors with high volatility. In addition, the purity, evaporation characteristics and thermostability of adopted precursors in the whole process would decide the quality and reproducible results of YBCO film. In the present report, the barium precursor containing 2,2,6,6-tetramethylheptane-3,5-dionate and tetraethylenepentamine ligands (Ba(TMHD)-tetraen) was synthesized and identified by FTIR, 1H NMR, 13C NMR and ESI-MS spectroscopy. Subsequently the thermal property and the kinetics of decomposition were systematically investigated by combining non-isothermal thermogravimetric analysis methods (TGA), Ozawa, Kissinger and Friedman methods. On the basis of the apparent activation energy of the evaporation process, the thermostability and evaporation characteristics of the precursors were discussed. All results show that Ba(TMHD)-tetraen has higher volatility than Ba(TMHD)2, but it is unstable and highly sensitive to the change of temperature during the whole evaporation process. Therefore, it is very important to choose suitable volatilization technology and conditions for avoiding Ba(TMHD)-tetraen breakdown (or thermal aging) during the MOCVD process.

Synthesis, characterization and thermostability of tris（2,2,6,6-tetramethyl-3,5- heptanedionato）yttrium（III）

Abstract The metal-organic chemical vapor deposition (MOCVD) technique is a promising process for high temperature superconductor YBa 2 Cu 3 O 7- d (YBCO) preparation. In this technique, the purity, evaporation characteristics and thermostability of adopted precursors will decide the quality and reproducible results of YBCO film. In the present report, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)yttrium(III) (Y(TMHD) 3 ) was synthesized by the interaction of yttrium nitrate hydrate with TMHD in methanol solution, and its structure was identified by FTIR, 1 H NMR, 13 C NMR and EI-MS spectroscopy. Subsequently, the thermal property and the kinetics of decomposition were systematically investigated by non-isothermal thermogravimetric analysis methods (TGA) at different heating rates in streams of N 2 , and the average apparent activation energy of evaporation process was evaluated by the Ozawa, Kissinger and Friedman methods. The possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 88.9 kJ/mol.