Titanium oxide Films Prepared by Sputtering, Sol Gel and Dip Coating Methods for Photovoltaic Application

AbstractDye-sensitized solar cells (DSCs) without using transparent conducting oxides (TCO) electrode can be produced at much lower cost with a flexible structure. A new type of DSCs using flexible stainless steel mesh sheets based electrode is reported in this research. The working electrode of DSCs is processed with conductive and flexible stainless mesh coated with metal oxides (TiO2) layer either by sputtering, sol gel or dip coating methods. Structures of the TCO-less DSCs sample is a stainless mesh for working electrode/dye sensitized TiO2 layer/liquid type electrolyte with polymer film/Pt doped Ti plate for counter electrode. The metal oxide coated stainless mesh sample showed higher photo-current conversion efficiency in general. The best cell performance in this experiment showed the efficiency of 3.11% (Voc = 0.58V, Jsc = 11.98mA/cm2, ff = 0.45)

Nearly Massless Electrons in the Silicon Interface with a Metal Film

We demonstrate the realization of nearly massless electrons in the most widely used device material, silicon, at the interface with a metal film. Using angle-resolved photoemission, we found that the surface band of a monolayer lead film drives a hole band of the Si inversion layer formed at the interface with the film to have nearly linear dispersion with an effective mass about 20 times lighter than bulk Si and comparable to graphene. The reduction of mass can be accounted for by repulsive interaction between neighboring bands of the metal film and Si substrate. Our result suggests a promising way to take advantage of massless carriers in silicon-based thin-film devices, which can also be applied for various other semiconductor devices.Comment: 4 pages, 4 figures, accepted for publication in Physical Review Letter

EFFECTS OF MO, CR, AND V ADDITIONS ON TENSILE AND CHARPY IMPACT PROPERTIES OF API X80 PIPELINE STEELS

In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.X1126sciescopu