Abstract

Various types of aggregates have been studied in Langmuir–Blodgett-type monolayers of selected pyridine and hemicyanine dyes. Environmental changes such as protonation or admixture of chromophores with opposite donor–acceptor characteristics result in dramatic changes of the measured surface susceptibility ${\overline{\chi }}^{(2)}$. Both enhanced ${\overline{\chi }}^{(2)}$ values in H aggregates following the shape of the linear absorption band and vanishing ${\overline{\chi }}^{(2)}$ values of antiparallel dimers or aggregates have been observed. The experimental results suggest that linear and nonlinear measurements need to be considered for a correct interpretation of the experimental results on monolayer aggregation.

© 1989 Optical Society of America

Aggregation-induced second-harmonic generation

Geoffrey J. Ashwell, Paul Leeson, Gurmit S. Bahra, and Christopher R. Brown
J. Opt. Soc. Am. B 15(1) 484-488 (1998)

Second-harmonic generation in Langmuir–Blodgett monolayers of stilbazium salt and phenylhydrazone dyes

Donald Lupo, Werner Prass, Ude Scheunemann, Andre Laschewsky, Helmut Ringsdorf, and Isabelle Ledoux
J. Opt. Soc. Am. B 5(2) 300-308 (1988)

Study of diacetylene monomer and polymer monolayers using second- and third-harmonic generation

G. Berkovic, R. Superfine, P. Guyot-Sionnest, Y. R. Shen, and P. N. Prasad
J. Opt. Soc. Am. B 5(3) 668-673 (1988)

Second-harmonic generation in mixed hemicyanine: fatty-acid Langmuir–Blodgett monolayers

I. R. Girling, N. A. Cade, P. V. Kolinsky, R. J. Jones, I. R. Peterson, M. M. Ahmad, D. B. Neal, M. C. Petty, G. G. Roberts, and W. J. Feast
J. Opt. Soc. Am. B 4(6) 950-955 (1987)

Determination of molecular orientation in molecular monolayers by second-harmonic generation

T. G. Zhang, C. H. Zhang, and G. K. Wong
J. Opt. Soc. Am. B 7(6) 902-907 (1990)