An Organic Metal/Silver Nanoparticle Finish on Copper for Efficient Passivation and Solderability Preservation

For the first time, a complex formed by polyaniline (in its organic metal form) and silver has been deposited on copper in nanoparticulate form. When depositing on Cu pads of printed circuit boards it efficiently protects against oxidation and preserves its solderability. The deposited layer has a thickness of only nominally 50 nm, containing the Organic Metal (conductive polymer), polyaniline, and silver. With >90% (by volume), polyaniline (PAni) is the major component of the deposited layer, Ag is present equivalent to a 4 nm thickness. The Pani–Ag complex is deposited on Cu in form of about 100 nm small particles. Morphology, electrochemical characteristics, anti-oxidation and solderability results are reported

Polyacetylene, (CH)/sub x/, as an emerging material for solar cell applications. Second quarterly technical progress report, July-September 1979

As of the starting date of this contract, a variety of rectifying junctions had been fabricated using doped and undoped (CH)/sub x/. Schottky diodes formed between metallic AsF/sub 5/-doped (CH)/sub x/ and n-type semiconductors indicate high (CH(AsF/sub 5/)/sub y/)/sub x/ electronegativity. The p-type character of undoped trans-(CH)/sub x/ was confirmed by Schottky barrier formation with low work function metals. An undoped p-(CH)/sub x/:n--ZnS heterojunction solar cell has been demonstrated with open circuit photovoltage of 0.8 V. These results point to the potential of (CH)/sub x/ as a photosensitive material for use in solar cell applications. The devices fabricated in initial experiments fall into three categories: 1) Schottky diodes utilizing heavily doped (CH)/sub x/ as a metallic electrode on a variety of n-type semiconductors, 2) Schottky diodes utilizing undoped (CH)/sub x/ as a p-type semiconductor on which metallic contacts are placed, and 3) p-n heterojunction diodes formed at the inferface of undoped p-type (CH)/sub x/ on n-ZnS. Progress is reported. (WHK

Polyacetylene, (CH)/sub x/, as an emerging material for solar cell applications. Final technical report, March 19, 1979-March 18, 1980

Despite great theoretical and technological interest in polyacetylene, (CH)/sub x/, the basic features of its band structure have not been unambiguously resolved. Since photoconductivity and optical absorption data have frequently been used to infer information on the band structure of semiconductors, such measurements were carried out on (CH)/sub x/. The main results of an extensive study of the photoconductivity (..delta.. sigma/sub ph/) and absorption coefficient (..cap alpha..) in (CH)/sub x/ are presented. The absence of photoconductivity in cis-(CH)/sub x/, despite the similarity in optical properties indicates that ..delta.. sigma/sub ph/ in trans-(CH)/sub x/ is induced by isomerization. It is found that isomerization generates states deep inside the gap that act as safe traps for minority carriers and thereby enhance the photoconductivity. Compensation of trans-(CH)/sub x/ with ammonia appears to decrease the number of safe traps, whereas acceptor doping increases their number. Thus, chemical doping can be used to control the photoconductive response. The energy of safe traps inside the gap is independent of the process used to generate them; indicative of an intrinsic localized defect level in trans-(CH)/sub x/. A coherent picture based on the soliton model can explain these results, including the safe trapping

Polyacetylene, (CH)/sub x/, as an emerging material for solar cell applications. Technical progress report, October, November, December 1979

Initial studies of p-n heterojunctions formed between undoped trans-(CH)/sub x/ and n-CdS are reported. The junctions were characterized by measurements of current vs voltage (I-V), capacitance vs voltage (C-V), and photovoltaic response spectra. The results are analyzed in terms of the standard heterojunction equations. It is concluded that undoped as-grown films of trans-(CH)/sub x/ are p-type with a residual acceptor concentration of 2 x 10/sup 18/ cm/sup -3/, and that in spite of the complex fibril morphology the semiconductor properties can be inferred by treating (CH)/sub x/ as an effective homogeneous medium. Detailed studies of the photovoltaic response at energies below the energy gap for (CH)/sub x/ imply the existence of a well-defined deep trapping state in polyacetylene with an energy near the center of the gap

POLARON-SOLITON MODEL FOR MACROSCOPIC CONDUCTION IN DOPED POLYACETYLENE

Un modèle pour la conductivité macroscopique dans le (CH)x dopé (0,2%-7%) est décrit.A model for macroscopic conduction in doped (0.2%-7%) (CH)x is presented