Z-type Langmuir-Blodgett films of a three-component optically nonlinear dye

Langmuir-Blodgett (LB) films of N-octadecyl-4-[(4-dimethylaminophenyl)azo]pyridinium iodide are Y-type and consequently the second-harmonic intensity is modest when the number of layers is odd and negligible when even. However, the required non-centrosymmetric structural arrangement may be obtained by combining the cationic dye in a 1:1:1 ratio with an amphiphilic ammonium cation and a complex dianion; the second-harmonic intensity from LB films of [N-octadecyl-4-[(4-dimethylaminophenyl)azo]pyridinium](+)[dioctadecyldimethylammonium](+)[bis(2-thione-1,3-dithiol-4,5-dimercapto)zinc](2-) then increases as I-2 omega(N) = I2 omega(1)N2, where N is the number of layers. The films have an effective second-order susceptibility of chi(eff)((2)) = 10 pm V-1 at 1.064 mu m. (C) 1999 Elsevier Science B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000082050900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, PhysicalSCI(E)EICPCI-S(ISTP)