Langmuir and Langmuir−Blodgett Films of NLO Active 2-(p-N-Alkyl-N-methylamino)benzylidene-1,3-indandioneπ/A Curves, UV−Vis Spectra, and SHG Behavior

• DOI: 10.1021/jp0038916
• Publication Date: 2002-07-26T06:08:28Z
• Authors: Hanna Schwartz; Royi Mazor; Vladimir Khodorko...; Lev Shapiro; Jacob T. Klug; Efim Kovalev; Guilia Meshulam; Garry Berkovic; Zvi Kotler; Shlomo Efrima
• Keywords: Absorbance; Deposition; Surface pressure

We study 2-(p-N-hexadecyl-N-methylamino)benzylidene-1,3-indandione (1a) as a model compound for the preparation of nonlinear optically (NLO) active Langmuir−Blodgett (LB) layers. The pressure−area (π−A) isotherm at air−water interface is investigated. A limiting area 0.60 ± 0.02 nm2 per molecule found. alternate-layer LB deposition and an inert spacer, cadmium stearate, different surface pressures performed. effects temperature delay time between spreading Langmuir film films are studied. An increase collapse pressure from 20 to 30 mN/m observed increases. UV−vis spectra indicate uniform transfer show compression-induced changes function conditions. split absorption maximum deposited higher lower temperatures. two bands can result molecular electronic transitions, affected by aligning influence surface, environments in compared solution. Alternatively, these be associated with (at least) conformers. orientation transition moments evaluated on basis polarized angles incidence, found 40−44°. Significant second harmonic (SH) generation observed. Analysis SH response gives tilt angle 44°, agreement finding UV absorbance.