Fluorescence detection and imaging of organic monolayer

Amino-terminated organic monolayer formed on silicon covered with native oxide (SiO2/Si) was directly visualized under observation with fluorescent microscopy. This successful fluorescence visualization was achieved by a combination of fluorescamine method and photopatterning of the arnino-terminated surface. As a typical example, an amino-terminated self-assembled monolayer (SAM) was formed on SiO2/Si substrate in a vapor of 12.5 vol.% solution of N-(6-aminohexyl)-3-aminopropyltrimethoxysilane [H2N(CH2)(6)NH(CH2)(3)Si(OCH3)(3), AHAPS] diluted with absolute toluene. A micropattern of AHAPS-SAM was photolithographycally prepared using 172 mn vacuum ultraviolet (VUV) light under a reduced pressure of 10 Pa for 30 min through a photomask. The resultant micropattern composed of AHAPS- and SiOH-covered regions was provided to fluorescamine method. Due to a nonluminescence of fluorescamine itself under UV/visible irradiation, a fluorescent emission could not be observed on SiOH regions of the micropattern. In contrast, fluorescamine reacted with the outermost amino group of the AHAPS-SAM to give a fluorescent emission. A comprehensible fluorescence method for verifying formation of an amino-terminated organic monolayer has been developed. (c) 2007 Elsevier B.V. All rights reserved.