Time-resolved third-order non-linear optical susceptibility of Langmuir-Blodgett films of mixed dimers ZnP(N+C22)4/H2Pc TS4− by femtosecond laser spectroscopy

1994 ◽  
Vol 244 (1-2) ◽  
pp. 981-984 ◽  
Author(s):  
K.D. Truong ◽  
A.D. Bandrauk ◽  
T.H. Tran-Thi ◽  
P. Grenier ◽  
D. Houde ◽  
...  
1992 ◽  
Vol 208 (1) ◽  
pp. 137-144 ◽  
Author(s):  
W.M.K.P. Wijekoon ◽  
B. Asgharian ◽  
P.N. Prasad ◽  
T. Geisler ◽  
S. Rosenkilde

1998 ◽  
Vol 51 (7) ◽  
pp. 599 ◽  
Author(s):  
Geoffrey J. Ashwell ◽  
Patricia C. Williamson ◽  
Andrew Green ◽  
Gurmit S. Bahra ◽  
Christopher R. Brown

Langmuir films of the title compound, 2,4-bis[4-(dibutylamino)phenyl]squaraine, Sq0, and its substituted analogues, Sq1 (monohydroxy) to Sq4 (tetrahydroxy), exhibit three well defined phases at the air–water interface: λmax 525–550 nm (H-aggregate); 660–670 nm (intermediate); 760–770 nm (J-aggregate). The monolayer spectra are influenced by the surface pressure and the number of hydroxy substituents and, when the monolayers are transferred to a solid substrate, there is a correlation between the linear and non-linear optical behaviour of the Langmuir-Blodgett films. Second-harmonic generation has been observed even though the unit molecular structures of two analogues, Sq0 and Sq4, are centric. The behaviour is aggregation-induced and there is evidence that the dyes associate in dilute solution. The electrospray ionization mass spectra exhibit peaks with high mass/charge (m/z) ratios; the data conform to the dimeric aggregate and, for solutions of two or more squaraines, corroborate the existence of heteromolecular associates.


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