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Epitaxial films of the solid solution Ga1-x In x N (up to X=0.42) have been fabricated on (0001) sapphire substrates by metalorganic vapor phase epitaxy (MOVPE) at 500°C. The properties of the films have been studied by the reflection high-energy electron diffraction technique, X-ray diffraction, and electrical and optical measurements. The fundamental absorption edge of the film decreases linearly with composition (up to X=0.42) from 3.20 eV to 2.01 eV at room temperature.

A rechargeable all-plastic battery was fabricated using (CH)x film as the electrode active material and P V D F . LiC104 9 PC [LiC1OJPC in polyvinylidene fluoride (PVDF)] film as the electrolyte. The (CH)x/PVDF 9 LiC104 9 PC/(CH)x battery exhibited an open-circuit voltage of 3.4V, and an initial short-circuit current of 13 m A (weight of (CH)x electrode: ca. 4 rag; doping level, y = 0.008). E x p e r i m e n t a l energy density of 47 Wh/kg was obtained based on the weight of (CH)x film (weight

The electrical properties of poly(3‐methylthiophene) (P3MT) films synthesized by electrochemical polymerization and the discharge characteristics of secondary batteries utilizing P3MT film as the cathode‐active material are described. The P3MT was synthesized in film forms by electrochemical polymerization in the propylene carbonate solutions containing LiBF4 or LiAsF6 . The conductivity of the AsF6− doped [30 mole percent (m/o)] P3MT film prepared at 25°C was about 200 S/cm. A P3MT/LiBF4+PC+EC/normalAl (PC:propylene carbonate, EC:ethylene carbonate) battery was charged and discharged over 1200 cycles at the doping level of 9% while the coulombic efficiency maintained over 97%. The discharge characteristics are described in relation to the surface morphology of the films. This battery exhibited an energy density of 326 Wh/kg based on the weight of the electrode active material at a doping level of 35%. The self‐discharge of this battery was relatively small.

An n-(CH)/LiClO4/p-(CH) battery (1.0 M LiClO4 in propylene carbonate) prepared by passing 2.14 C (dopant concentration y=0.072) exhibited an open-circuit voltage of 3.5 V and an initial short-circuit current of 28 mA ((CH)x electrode; ∼4 mg). Experimental energy density of 424 W-hr/Kg (at a stored charge of 10.8 C (y=0.364), a liberated charge of 4.52 C and a mean voltage of 2.7 V) was obtained based on the weight of the (CH) x film (both electrodes; ∼8 mg). No degradation of the polyacetylene battery was observed even after 2000 successive charge/discharge cycles, each cycle consisting of a 10 min discharge at a constant resistance of 50 kΩ and a 10 min charge at 0.1 mA (a stored charge of 0.06 C (y=0.002)).