ENHANCEMENT OF 3RD-ORDER OPTICAL NONLINEARITY OF POLY(ARYLENEETHYNYLENE)S BY INTRODUCING AN INTRAMOLECULAR CHARGE-TRANSFER INTERACTION INTOTHEIR PI-CONJUGATION
N. Ooba et al., ENHANCEMENT OF 3RD-ORDER OPTICAL NONLINEARITY OF POLY(ARYLENEETHYNYLENE)S BY INTRODUCING AN INTRAMOLECULAR CHARGE-TRANSFER INTERACTION INTOTHEIR PI-CONJUGATION, JPN J A P 1, 34(6A), 1995, pp. 3139-3141
Poly(aryleneethynylene) type pi-conjugated polymers (PAEs) are synthes
ized and the third-order optical susceptibility ((3)(chi)) of their th
in films is evaluated. There is a red-shift in the electronic absorpti
on of the PAE caused by an intramolecular charge transfer (CT) interac
tion when pi-electron excessive heteroaromatic rings are introduced in
to the pi-conjugation. The ((3)(chi)) value of the PAEs is enhanced by
increasing the CT interaction and reaches more than 10(-11) esu in th
e near resonant region. The increase in the pi-electron delocalization
caused by the CT interaction is found to be the main factor enhancing
((3)(chi)). This introduction of a CT interaction into a pi-conjugati
on is an effective concept for the design of large ((3)(chi)) material
s.