Theoretical Quantification of the Modified Photoactivity of Photochromes Grafted on Metallic Nanoparticles

We present a quantum-mechanical study of the photoactivity of nanoscale architectures based on dithienylethene (DTE) photochromic molecules grafted onto plasmonic gold or silver nanoparticles (NPs). The effects of the metal NPs are included in each step of the quantum-mechanical description through the polarizable continuum model. By a direct comparison with measured data, we demonstrate that such a multiscale model is able to provide a reliable quantification of the spectroscopic parameters characterizing the photoactivity of the switches as well as their evolution under the influence of the plasmonic effects. In particular, both the calculated enhancement factors describing the modification of the DTE photoreactivity close to the NP and the calculated cyclization/cycloreversion quantum yields accounting for the efficiency of the photochromism are in good agreement with the experimental data. In addition, a better understanding of the photoinduced behavior of such complex nanoscaled photochromic systems is given in terms of a molecular-level description.