Plasmon induced polymerization using a TERS approach: a platform for nanostructured 2D/1D material production

Abstract

Plasmon-induced chemical reactions have recently attracted great attention as a promising method for high efficiency light-energy conversion and proved to be useful in a wealth of different domains of chemistry and physics. One of the interesting and, so far, less explored avenues of such reactions is their potential for efficient, highly localized and controlled polymer production. Here, we present the first example of a localized, directed plasmon catalyzed polymerization process of a self-assembled monolayer on both silver and gold surfaces monitored by surface- and tip-enhanced Raman spectroscopy (SERS and TERS). As a proof-of-concept, a bi-functionalized dibenzo(1,2)dithiine-3,8-diamine (D3ATP) molecule that undergoes a well-known plasmon-induced coupling via the amino group into an azo group has been used. Initial dimerization is demonstrated using established marker bands associated with the formation of the azo group. A subsequent indicator for a polymerization reaction, the appearance of a new characteristic band, is monitored by time-dependent SERS and TERS experiments. We demonstrate that the dimerization reaction and hence, the subsequent polymerization, can be induced by a plasmonic feature, e.g. a TERS tip, at specific nanoscale locations and, at a much larger micron scale, by continuously scanning the plasmonic probe. The presented results provide the basis for designing further plasmonic catalysis experiments in general, and offer a new platform for producing ultra-thin polymer films with a defined structural dimension.