No abstract

PSS are well preserved during the mechanical deformation.

Deformation behavior of the Ag nanowire flexible transparent electrode under bending strain is studied and results in a novel approach for highly reliable Ag nanowire network with mechanically welded junctions. Bending fatigue tests up to 500,000 cycles are used to evaluate the in situ resistance change while imposing fixed, uniform bending strain. In the initial stages of bending cycles, the thermally annealed Ag nanowire networks show a reduction in fractional resistance followed by a transient and steady-state increase at later stages of cycling. SEM analysis reveals that the initial reduction in resistance is caused by mechanical welding as a result of applied bending strain, and the increase in resistance at later stages of cycling is determined to be due to the failure at the thermally locked-in junctions. Based on the observations from this study, a new methodology for highly reliable Ag nanowire network is proposed: formation of Ag nanowire networks with no prior thermal annealing but localized junction formation through simple application of mechanical bending strain. The non-annealed, mechanically welded Ag nanowire network shows significantly enhanced cyclic reliability with essentially 0% increase in resistance due to effective formation of localized wire-to-wire contact.

The enhancement of the electrical conductivity by doping is important in hematite (α-Fe(2)O(3)) photoanodes for efficient solar water oxidation. However, in spite of many successful demonstrations using extrinsic dopants, such as Sn, Ti, and Si, the achieved photocurrent is still lower than the practical requirement. There is still lack of our understanding of how intrinsic oxygen defects can change the photocurrent and interact with the extrinsic dopants. In this study, we systematically investigate the interplay of oxygen vacancies and extrinsic Sn dopants in the context of photoanodic properties. As a result, we demonstrate that the controlled generation of oxygen vacancies can activate the photoactivity of pure hematite remarkably and further enhance the Sn doping effects synergistically. Furthermore, the correlated behavior of oxygen vacancies and Sn dopants is closely linked to the variation of electrical conductance and results in the optimum concentration region to show the high photocurrent and low onset voltage.

Atomic migration under an electric field, electromigration, in molten and crystalline Ge2Sb2Te5 was studied using a pulsed dc stress to an isolated line structure. Under a single pulse (∼10−3 s), Ge2Sb2Te5 was melted by Joule heating, and an electrostatic force-induced drift of Ge and Sb toward the cathode and Te toward the anode was observed. Effective charge numbers were calculated to be 0.28, 0.38, and −0.29 for Ge, Sb, and Te, respectively. Electromigration in the crystalline state was studied by applying a 10 MHz pulsed dc; constituent elements migrated toward the cathode, which suggests a hole wind-force operating in this phase.