Spherical Sn0.3Ag0.7Cu (wt.%) solder droplets with diameter ranging from 70.6 to 334.0 µm were prepared using pulsated orifice ejection method. Compared with conventional atomization, these droplets are almost completely spherical with a much narrower size distribution. The surface of these droplets is smooth without detectable satellite particles. Furthermore, both the composition and microstructure are homogenous throughout any single droplet regardless of their size. Detailed microstructural analysis shows that nano-sized Ag3Sn particles are distributed homogenously in the β-Sn matrix. The results suggest that the droplets have advantage as electronic packaging material and be a promising candidate material for three-dimensional printing.

We deposited TaWSi amorphous metal thin films to determine how composition affects film crystallization and oxidation at high temperatures. Films were deposited by magnetron sputtering from targets of nominal compositions Ta : W : Si = 40 : 40 : 20, 30 : 50 : 20, and 30 : 30 : 40, and studied by electron probe microanalysis, electron microscopy, electrical methods, x-ray diffraction, x-ray photoelectron spectroscopy, and atomic-force microscopy. All films remained amorphous to 800 °C or higher temperatures. Films prepared from the target composition 30 : 30 : 40 yielded the film composition Ta41.7W38.4Si19.9, which retained its film integrity and amorphous structure to 1100 °C, even after annealing in air.

In our paper, yttrium aluminum garnet doped with cerium (YAG:Ce) and terbium aluminum garnet doped with cerium (TAG:Ce) yellow garnet phosphors were prepared by a modified sol–gel method, using oxide, nitride as raw materials and acetylacetone, dimethyl sulfoxide, cetrimonium bromide in the hydrolysis and condensation step. The thermal treatment of the phosphors was performed at 1100 °C in order to transform it from amorphous to crystalline garnet phase. Structural, morphological, and luminescence properties were studied by Fourier transform infrared spectrometry, x-ray diffraction, scanning electron microscopy, and fluorescence spectroscopy. The results show that the modified sol–gel method provides a feasible approach to produce YAG:Ce and TAG:Ce yellow phosphors for the optoelectronic applications.

The effect of p-type doping at ultra-low concentrations (~10−4–10−5 monomer mol fraction) of the polymer poly(3-hexylthiophene) (P3HT) is studied using charge modulation (CM) spectroscopy. Quantitative analysis of CM spectra of doped P3HT show that dopants induce measurable changes in the P3HT local chain conformation. We find that the dopants reside in both the aggregate and amorphous regions of the polymer, not just in the amorphous regions, as previously assumed. With increased doping, the P3HT intrachain disorder grows, causing the P3HT chains to become more oligomer-like, which we postulate leads to the drop in mobility commonly observed in literature.