Picosecond Generation of Transient Charge Carriers in Langmuir-Blodgett Films of Semi-Amphiphilic Heterodimers

Thu Hoa Tran Thi (1) , Jean-François Lipskier (1) , Daniel Houde (2) , Claude Pépin (2) , R. Langlois (2) , Serge Palacin (1)

1 SCM - Service de Chimie Moléculaire
2 Sherbrooke - Laboratoire de Spectroscopie Optique Ultrarapide

Langmuir-Blodgett homolayers are formed by deposition of semi-amphiphilic porphyrin-phthalocyanine heterodimers. The optical and photophysical properties of these dimers have been investigated and compared to the liquid-phase data. Excitation of the dimer results in an instantaneous formation of the singlet excited states, followed by a very efficient charge-transfer reaction. The oxidized porphyrin and reduced phthalocyanine moieties are formed within 2 ps and disappear in 70 ps. The triplet excited states of the porphyrin issued from the intersystem crossing decay pathway of the singlet excited states are formed with a very low quantum yield. They also undergo a charge-transfer reaction, leading to the formation of long-lived transient charge carriers. The photoprocesses determined in the Langmuir-Blodgett films of semi-amphiphilic porphyrin-phthalocyanine heterodimers are almost identical to those previously observed for the same dimers in the liquid phase.

Domains: Chemical Sciences; Material chemistry

Thu Hoa Tran Thi, Jean-François Lipskier, Daniel Houde, Claude Pépin, R. Langlois, et al.. Picosecond Generation of Transient Charge Carriers in Langmuir-Blodgett Films of Semi-Amphiphilic Heterodimers. Journal of the Chemical Society, Faraday Transactions, 1994, 88, pp.2529-2535. ⟨10.1039/FT9928802529⟩. ⟨cea-01057135⟩