Speaker
Description
The field of smart materials, whose properties can be modified in response to an external stimulus, is currently experiencing rapid growth. Among the various stimuli available, light is particularly attractive for controlling materials, as it is readily accessible, biocompatible, non-invasive, and, most importantly, allows excitation with high spatial and temporal resolution. In this context, organic photochromic compounds have been extensively studied and incorporated into materials for a wide range of applications. Photoswitchable compounds are organic molecules capable of reversibly switching from a stable form to a metastable form upon light irradiation. These two photochromic states exhibit different absorption spectra and often display distinct geometries, solubilities, and physicochemical properties. It is precisely this difference in properties between the two states that is exploited in photoactive materials for applications such as chemical and biological sensing, targeted delivery of bioactive molecules, photosensitive catalysis, energy storage, and information storage. In this work, the project aims to design photoresponsive self-assembled monolayers (SAMs) functionalized with nonlinear optical (NLO) photoswitches. The structure–property relationships governing the linear and nonlinear optical responses in solution were investigated in a range of azobenzene (AZO) and Donor–Acceptor Stenhouse Adduct (DASA) derivatives. These photoswitches, bearing an alkyne end group, were then covalently grafted onto an azide-terminated monolayer platform to afford photoresponsive monolayers. The resulting materials were characterized using classical surface analysis techniques such as contact angle goniometry, PM-IRRAS, and ToF-SIMS, as well as advanced optical characterization methods. The unique combination of Visible Reflection–Absorption Spectroscopy and Second Harmonic Generation spectroscopy not only allows the assessment of nonlinear optical responses, but also provides unique insight into intrinsic monolayer properties, including surface density and molecular orientation distribution.
| Keyword-1 | Photoswitches |
|---|---|
| Keyword-2 | Self-Assembled Monolayers |
| Keyword-3 | Second Harmonic Generation |