Thermoelectric (Peltier) heat pumps are capable of refrigerating solid or fluid objects, and unlike conventional vapor compressor systems, they can be miniaturized without loss of efficiency. More efficient thermoelectric materials need to be identified, especially for low-temperature applications in electronics and devices. The material CsBi(4)Te(6) has been synthesized and its properties have been studied. When doped appropriately, it exhibits a high thermoelectric figure of merit below room temperature (ZT(max) approximately 0.8 at 225 kelvin). At cryogenic temperatures, the thermoelectric properties of CsBi(4)Te(6) appear to match or exceed those of Bi(2-x)Sb(x)Te(3-y)Se(y) alloys.

Polyfuran films have been synthesized by electropolymerization of terfuran and investigated as a function of film preparation conditions in both the doped and undoped state. These films have been characterized by infrared spectroscopy, scanning electron microscopy, optical absorption, X-ray photoelectron spectroscopy, dc conductivity, and electron spin resonance measurements. The electrolyte anion (dopant) used for the preparation of these films heavily influences the -conjugated system of the polymer backbone. Structural disorder and doping level depends on the nature of the electrolyte anion. CF3SO3-was found to be the best dopant and to cause the least structural disorder or furan ring opening. Electrical conductivities as high as 2 X 10-3 S/cm were obtained in the CFsSOs'-doped state. The temperature dependence of the electrical conductivity indicates a thermally activated process with semiconductorlike behavior. The charge transport properties are explained in terms of polaron and bipolaron states. The polymer band gap was measured at 2.35 eV.

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Equilibrium phase relationships in the ZnO-In 2 O 3 system were determined between 1100°and 1400°C using solidstate reaction techniques and X-ray diffractometry. In addition to ZnO and In 2 O 3 , nine homologous compounds, Zn k In 2 O k+3 (where k = 3, 4, 5, 6, 7, 9, 11, 13, and 15), were observed. Electrical conductivity and diffuse reflectance of the k = 3, 4, 5, 7 and 11 members were measured before and after annealing at 400°C for 1 h under forming gas (4% H 2 -96% N 2 ). Room-temperature conductivity increased as k decreased, because of increased carrier concentration as well as increased mobility. In general, transparency in the wavelength range of 450-900 nm increased as k increased. Reduction in forming gas resulted in increased conductivity and reduced transparency for all compounds measured. The highest room-temperature conductivity measured, 270 S/cm, was that of reduced Zn 3 In 2 O 6 .

have shown that this method yields negligible contact resistance and highly accurate conductivity values.5 Registry No. PP, 30604-81-0; PMT, 84928-92-7.(5) Conductivity values for homogeneous PP films were obtained by using this method and the more conventional four-point method; identical values were obtained. The four-point method cannot be used on these ultranarrow fibers.(6) The surface layers are less than 200 nm thick and cover 100% of the surface area; the fibers are 10 µ long and occupy 1% (or less) of the surface area.Furthermore, for several membranes, we measured the resistance, scraped off the surface layers, and then remeasured the resistance; Rm values with and without the surface layers were identical.