J-aggregate formation of long-chain merocyanine dye in various mixed monolayers and its exciton behaviours in Langmuir-Blodgett films

• Published in: Thin solid films Vol. 178; no. 1; pp. 549 - 553
• Main Authors: Nakahara, Hiroo, Uchimi, Hideki, Fukuda, Kiyoshige, Tamai, Naoto, Yamazaki, Iwao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.1989
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(89)90352-0

J-Aggregate formation of a long-chain merocyanine dye in mixed monolayers with various lipid matrices such as glycerides, phospholipids and cholesterol was investigated. From visible absorption spectra and fluorescence microscopy, different extents of J-aggregate formation together with various morphologies have been observed in the LB films, depending on the matrix agents and the compositions. By applying the Urbach rule it has been revealed that exciton-phonon coupling is weak and fluorescence occurs by radiative annihilation from the free-exciton state. From the decay curves, fluorescence lifetimes of 40 and 230 ps were obtained, which were prolonged with increasing content of arachidic acid as a matrix. The fluorescence lifetime was shortened in the presence of an electron acceptor.