Femtosecond excited-state dynamics in fluoro- and chloroaluminum phthalocyanine thin films

V. S. Williams, S. Mazumdar, N. R. Armstrong, Z. Z. Ho, N. Peyghambarian

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Abstract

Photoinduced absorption on the high-energy side of the Q-band has been observed and time-resolved in polycrystalline/amorphous thin films of both fluoroaluminum and chloroaluminum phthalocyanine. The films were pumped with ≈100-fs optical pulses at various wavelengths inside the inhomogeneously broadened Q-band, including 620 and 760 nm. The induced absorption signal is accompanied by a bleaching signal on the low-energy edge of the Q-band. The bleaching signal resembles a blue-shifted monomer absorbance spectrum. The induced absorption signal develops as the absorption bleaching signal decays, suggesting exciton decay into a subgap state. The different bimolecular decay dynamics observed for the absorption bleaching (τeff ≈ 700 fs) and induced absorption (τeff ≈ 2 ps) signals support this conclusion. Analyses of the results and possible origins of the indicated subgap state are discussed.

Original languageEnglish (US)
Pages (from-to)4500-4505
Number of pages6
JournalJournal of physical chemistry
Volume96
Issue number11
DOIs
StatePublished - Jan 1 1992

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ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

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