Absorption spectra of rhodamine B dimers in dip-coated thin films prepared by the sol-gel method

✍ Scribed by Tsuneo Fujii; Hiromasa Nishikiori; Takuma Tamura

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 473 KB
• Volume: 233
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)01477-d

✦ Synopsis

Thin films including rhodamine B (RB) which were dip-coated using the sol-gel reaction of tetraethyl orthosilicate (TEOS) have been prepared as a function of time and their absorption spectra observed 72 h after preparation of the thin films. One monomer and two dimers (Hand J-types) are clearly and simultaneously resolved both for RB in the thin films and the water-ethanol mixed solvent. Just after mixing the reaction system, the proportion of the dimers for RB was significant, and the H and J dimer amounts were nearly equal. As the sol-gel reaction proceeded, the relative contribution from the monomer species increased. The relative contribution of the monomer to that of the dimers reached a constant value long before the gelation time. This behavior indicates that the dye molecules are encapsulated in a certain structural region (pores) long before the gelation point of the sol-gel reaction of TEOS.