550 K
19 pp.
 
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TitlePolyacetylene, (CH){sub x}, as an Emerging Material for Solar Cell Applications. Final Technical Report, March 19, 1979 - March 18, 1980
Author(s)Heeger, A. J.; MacDiarmid, A. G.
Publication DateJune 05, 1980
Report NumberDOE/ET/23002-T9
Unique IdentifierACC0443
Other NumbersOSTI ID: 5250751
Research OrgUniversity of Pennsylvania, Philadelphia (USA)
Contract NoAC04-79ET 23002
Sponsoring OrgU.S. Department of Energy (DOE)
Subject14 Solar Energy; Acetylene; Absorptivity; Photoconductivity; Polymers; Solar Cells; Semiconductor Materials; Ammonia; Crystal Defects; Electric Conductivity; Energy Gap; Experimental Data; Graphs; Isomerization; Traps; Alkynes; Chemical Reactions; Crystal Structure; Data; Data Forms; Direct Energy Converters; Electrical Properties; Equipment; Hydrides; Hydrocarbons; Hydrogen Compounds; Information; Materials; Nitrogen Compounds; Nitrogen Hydrides; Numerical Data; Optical Properties; Organic Compounds; Photoelectric Cells; Photovoltaic Cells; Physical Properties; Solar Equipment
Related Web PagesAlan MacDiarmid, Conductive Polymers, and Plastic Batteries
AbstractDespite 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.
550 K
19 pp.
 
View Document 
  


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