Photoinduced Electron Transfer from a Conducting Polymer to Buckminsterfullerene

• Published in: Science (American Association for the Advancement of Science) Vol. 258; no. 5087; pp. 1474 - 1476
• Main Authors: Sariciftci, N. S., Smilowitz, L., Heeger, A. J., Wudl, F.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 27-11-1992; American Association for the Advancement of Science
• Subjects: Absorption spectra; Applied sciences; Buckminsterfullerene; Charge transfer; Conducting polymers; Electron donor-acceptor complexes; Electron paramagnetic resonance; Electron transfer; Exact sciences and technology; Ground state; Ions; Luminescence; Methods; Photochemistry; Physicochemistry of polymers; Polymers; Polymers and radiations; Properties and characterization; Solid state; Phenylene derivative polymer; Electron transfer; Photoinduced effect; Electrical conductor; Experimental study; Electron acceptor
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.258.5087.1474

Evidence for photoinduced electron transfer from the excited state of a conducting polymer onto buckminsterfullerene, C$_{60}$, is reported. After photo-excitation of the conjugated polymer with light of energy greater than the π-$\pi^*$ gap, an electron transfer to the C$_{60}$ molecule is initiated. Photoinduced optical absorption studies demonstrate a different excitation spectrum for the composite as compared to the separate components, consistent with photo-excited charge transfer. A photoinduced electron spin resonance signal exhibits signatures of both the conducting polymer cation and the C$_{60}$ anion. Because the photoluminescence in the conducting polymer is quenched by interaction with C$_{60}$, the data imply that charge transfer from the excited state occurs on a picosecond time scale. The charge-separated state in composite films is metastable at low temperatures.