Photoconductivity in trans-poly(phenylacetylene) and its charge-transfer complexes

Abstract

Steady-state and pulsed photoconductivities were explored in 4-8-/tm-thick films of poly-(phenylacetylene) (PPA) and PPA doped with some inorganic and organic electron-accepting compounds, particularly iodine and DDQ (2,. Data are reported on the dependence of the photocurrent density (Jph) on the exciting wavelength (X), the dopant concentration (Y), the light intensity (I), and the electric field (E) in frans-PPA. Jph(X) shows two regions of response, one at the t-tt* transition at X <525 nm, the other in the red and near-IR in doped, as well as undoped, PPA. The latter response is associated with photodetrapping from shallow electron traps in the undoped polymer and with charge carrier generation in the charge-transfer band in the doped polymer. The field dependence is superlinear at E 104-106 V/cm and </ph <x with a < 0.5. Carrier lifetimes and mobilities are reported for some conditions. Charge transport occurs by a bandlike mechanism that is modulated by shallow electron traps in the undoped polymer and by trapping in the charge-transfer complex in the doped polymer. The control of photoconductivity by the carrier recombination kinetics is an important characteristic of this semiconducting photoconductor.

Electric field induced cis-to-trans isomerization of polyphenylacetylene in solid state

“…The S values decrease with increasing cis-concentration ranging from 66.8 to 96.8%. Similar experimental results were previously reported by ourselves 5 and Kang et al, 10 the photoconductivity of PPA and its derivatives was mainly associated with the trans-segments on polymer chains. Fig.…”

UPS Spectra of the Polyacetylene Derivatives Carrying Stable Radical Substituents

“…Substituted polyacetylenes have recently attracted much attention due to their electrical conduction 1 -3 and photo conduction 4 based on their n-conjugation along the main chain. Recently there arises the possibility of unique magnetic interaction for polyacetylenes carrying stable radical substituents 5 • 6 and several model compounds have been reported.…”

Synthesis and Functionality of Substituted Polyacetylenes

“…Interfaces between amorphous and mesogen phases also favor photoconductions, for excitons dissociate efficiently at, and carriers move rapidly along, the interfaces. Indeed, LCPA 53 shows higher PC than PPA, a non-LC photoconductor [26]. LCPA 17(2) shows even higher PC, because of its better-ordered LC aggregates formed in the photoreceptor fabrication process.…”