Extremely stable graphene electrodes doped with macromolecular acid

Although conventional p-type doping using small molecules on graphene decreases its sheet resistance (Rsh), it increases after exposure to ambient conditions, and this problem has been considered as the biggest impediment to practical application of graphene electrodes. Here, we report an extremely stable graphene electrode doped with macromolecular acid (perfluorinated polymeric sulfonic acid (PFSA)) as a p-type dopant. The PFSA doping on graphene provides not only ultra-high ambient stability for a very long time (> 64 days) but also high chemical/thermal stability, which have been unattainable by doping with conventional small-molecules. PFSA doping also greatly increases the surface potential (similar to 0.8 eV) of graphene, and reduces its Rsh by similar to 56%, which is very important for practical applications. High-efficiency phosphorescent organic light-emitting diodes are fabricated with the PFSA-doped graphene anode (similar to 98.5 cd A(-1) without out-coupling structures). This work lays a solid platform for practical application of thermally-/chemically-/air-stable graphene electrodes in various optoelectronic devices

Measurement of the mass difference m(D-s(+))-m(D+) at CDF II

We present a measurement of the mass difference m(D-s(+))-m(D+), where both the D-s(+) and D+ are reconstructed in the phipi(+) decay channel. This measurement uses 11.6 pb(-1) of data collected by CDF II using the new displaced-track trigger. The mass difference is found to be m(D-s(+))-m(D+)=99.41+/-0.38(stat)+/-0.21(syst) MeV/c(2)

Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from p(p)over-bar Collisions at root s=1.96 TeV

We present the results of a search for a very light CP-odd Higgs boson a(1)(0) originating from top quark decays t -> H(+/-)b -> W-+/-(*) a(1)(0)b, and subsequently decaying into tau(+)tau(-). Using a data sample corresponding to an integrated luminosity of 2.7 fb(-1) collected by the CDF II detector in p (p) over bar collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t -> H(+/-)b for various masses of H-+/- and a(1)(0)

Electrical, magnetic and thermal properties of Pr0.6-xBixSr0.4MnO3 manganites

In the present communication, we report the electrical, magnetic and thermal properties of Bi-doped Pr0.6Sr0.4MnO3 (PSMO) compounds. These measurements show that the transition temperature decreases with Bi-content. Analyses on the measured electrical resistivity and thermoelectric power data indicate that the small polaron hopping model is operative in the high temperature paramagnetic phase for all samples. The thermal conductivity, kappa(T) for samples studied in the present work is found to be low which is essentially due to Jahn-Teller (JL) distortion in the samples. It is observed that kappa(T) is seen to decrease with increase in doping concentration of Bi which is possibly due to the formation of JT polarons which act as scattering centers. From specific heat measurements, we observe reduction in values of entropy change with increase in bismuth content which suggests that the magnetic inhomogeneity increases with Bi substitution