PHOTOINDUCED ELECTRON-TRANSFER REACTIONS IN MIXED FILMS OF PI-CONJUGATED POLYMERS AND A HOMOLOGOUS SERIES OF TETRACYANO-P-QUINODIMETHANE DERIVATIVES

Near-steady-state photoinduced absorption (PIA) and photoluminescence studies are presented on photoinduced electron transfer reactions from poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and poly[3-(2-(3-methylbutoxy)ethyl)thiophene] (P3MBET) as donors (D) onto a homologous series of tetracyano-p-quinodimethane (TCNQ) deriva tives containing fused aromatic rings as accepters (A) to systematical ly study the effect of acceptor electron affinity. We observe that com posite films of these D/A couples give rise to long-lived charge separ ated states upon photoexcitation, as evidenced from the formation of p olaron bands (radical cation absorption) in the PIA and the concomitan t loss of the metastable triplet PIA and photoluminescence that are ob served in pristine MEH-PPV and P3MBET. We find that the efficiency of the photoinduced electron transfer reaction correlates with the reduct ion potential of the accepters. (C) 1995 American Institute of Physics .