Characterization of the Chromophore Orientation of Rhodamine B Amphiphiles in Langmuir–Blodgett Monolayers

✍ Scribed by Ken-ichi Ishibashi; Osamu Sato; Ryo Baba; D.A. Tryk; Kazuhito Hashimoto; Akira Fujishima

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 57 KB
• Volume: 233
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2000.7273

✦ Synopsis

NOTE

Characterization of the Chromophore Orientation of Rhodamine B Amphiphiles in Langmuir-Blodgett Monolayers SHG (second harmonic generation) interferometry and linear dichroism measurements were applied to the characterization of Langmuir-Blodgett monolayers composed of rhodamine B derivatives on hydrophilic fused silica substrates. When excited with a Nd-YAG laser, the contribution of dimeric species composed of rhodamine B chromophores to the nonlinear optical behavior was large, even though the relative concentration of the dimers was small. This implies the formation of noncentrosymmetrically oriented dimers with a relatively higher nonlinear molecular susceptibility, β. Therefore, a unique phenomenon was observed; that is, the relative phase of the SH light shifted depending on the incident light polarization ( p and s). In addition, it was found that the relatively standing up orientation was favored for the dimer, while a strongly tilted orientation was favored for the monomer.