作者:Jingjing Cao、Shuaifan Wu、Baoqi Zhai、Qiaochun Wang、Jing Li、Xiang Ma
DOI:10.1016/j.dyepig.2013.11.017
日期:2014.4
The spiropyran monolayer covalently protected gold nanorod (GNR) hybrid was prepared and well characterized for the first time, which was stable, soluble and photo-responsive under certain light irradiation in organic solvent. The photochromism of the densely packed spiropyran monolayer on the surface of GNRs was found having effect on the surface plasmonic resonance (SPR) absorption of gold nanorods, namely inducing the intensity change of the two plasma absorption peaks at 786 and 551 nm of the GNR hybrids. The functionalization of this organic-inorganic GNR hybrid and the photo-tuning of its SPR absorption properties, especially in the not only UV-Vis range but also near-infrared (NIR) spectral area would make important and interesting sense in the area of functional hybrid nanomaterial. (C) 2013 Elsevier Ltd. All rights reserved.
Characterizing the Photoinduced Switching Process of a Nitrospiropyran Self-Assembled Monolayer Using In Situ Sum Frequency Generation Spectroscopy
作者:Tamim A. Darwish、Yujin Tong、Michael James、Tracey L. Hanley、Qiling Peng、Shen Ye
DOI:10.1021/la302204f
日期:2012.10.2
Sum frequency generation (SFG) vibrational spectroscopy is employed to investigate the reversible, photoinduced spiro -> merocyanine isomerization of a self-assembled monolayer, the result of attachment of nitrospiropyran to a gold surface using a dithiolane anchoring group. The attachment of these molecular "alligator clips" to spiropyran molecules provide an easily accessible method to self-assemble a robust monolayer of spiropyran on a gold surface, which allows photoswitching of the spiropyran units. Probing the symmetric and antisymmetric stretching modes of the nitro group allows the determination of the structural orientation of the charged moiety with respect to the surface normal as well as the isomerization rates under photoinduced switching conditions. The photoisomerization of the spiropyran SAM on the gold surface is much faster than the rates of switching spiropyrans in a solid crystalline form, and the rate of thermal relaxation of the opened to closed form in this study is found to be on the same time scale as the relaxation of spiropyran when present in solutions with polar solvents.