TY - JOUR
T1 - Physical insights into the photoactivated ullmann coupling process producing highly conjugated oligothiophene films on a copper substrate
AU - Natarajan, Sudarshan
AU - Liu, Guangming
AU - Kim, Seong
PY - 2006/4/20
Y1 - 2006/4/20
N2 - This paper describes the details of surface reactions producing > 100-nm-thick conjugated- polymer films. When 2,5-diiodothiophene films deposited on copper are irradiated with UV at room temperature in Ar environments, oligothiophene films are synthesized. The average conjugation length of the produced film varies from ∼7 to 3-4 as the film thickness increases from ∼100 to ∼500 nm. The X-ray photoelectron spectroscopy analysis of the produced films reveals evidence for the formation of organo-copper intermediate species at the copper-monomer film interface and their diffusion from the copper surface into the monomer film during the photochemical process. A one-dimensional diffusion-reaction model is presented to explain the formation, diffusion, and reaction of organo-copper intermediates in the multilayer film during the photochemical reaction. The model simulation results qualitatively explain the decrease of the Ullmann coupling contribution in the photochemical reaction with the film thickness.
AB - This paper describes the details of surface reactions producing > 100-nm-thick conjugated- polymer films. When 2,5-diiodothiophene films deposited on copper are irradiated with UV at room temperature in Ar environments, oligothiophene films are synthesized. The average conjugation length of the produced film varies from ∼7 to 3-4 as the film thickness increases from ∼100 to ∼500 nm. The X-ray photoelectron spectroscopy analysis of the produced films reveals evidence for the formation of organo-copper intermediate species at the copper-monomer film interface and their diffusion from the copper surface into the monomer film during the photochemical process. A one-dimensional diffusion-reaction model is presented to explain the formation, diffusion, and reaction of organo-copper intermediates in the multilayer film during the photochemical reaction. The model simulation results qualitatively explain the decrease of the Ullmann coupling contribution in the photochemical reaction with the film thickness.
UR - http://www.scopus.com/inward/record.url?scp=33646396191&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646396191&partnerID=8YFLogxK
U2 - 10.1021/jp0604239
DO - 10.1021/jp0604239
M3 - Article
C2 - 16610906
AN - SCOPUS:33646396191
VL - 110
SP - 8047
EP - 8051
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 15
ER -