• Jenneskens, Lw
• King, Jk
• Cleij, Thomas J.

Abstract

Chemical modification of poly(methylphenylsilane) 1 using triflate chemistry gave two series of random copolymers with different composition ratios, viz., poly(methylphenyl-co-4-dimethylaminophenylmethylsilane)s 3-7 and poly(methylphenyl-co-4-bromophenylmethylsilane)s 8-9. The optical and electronic properties of the copolymers have been studied and are compared with those of the homopolymers 1 and poly(4-dimethylaminophenyl-methylsilane) 2. Electrochemical measurements in THF/LiClO4 give strong evidence that, in marked contrast to the results observed for 1 and 2, the onset of oxidation (V-i) of 3-7 and 8-9, respectively, does not represent the silicon backbone valence band. Instead, in these copolymers, a mixture of decoupled electronic domains exists of which those possessing the lowest V-i govern the electrochemical response. As a consequence, the radical cations become confined, i.e. localization occurs. This interpretation is further supported by fluorescence emission spectroscopy, the presence of a confined exciton is indicated by the appearance of an additional broad band for the copolymers. Remarkably, copolymers with optical and electronic properties comparable to those of 3-7 are also accessible by (reversible) protonation of the 4-dimethylamino substituents of 2.

Topics

• impedance spectroscopy
• Silicon
• random
• copolymer
• homopolymer
• random copolymer