Abstract
The covalent surface functionalization of carbon nanodots (CNDs) can facilitate the design and development of nanocarbon hybrids with photoswitching properties, which can be applied in a wide range of applications, including sensing, optoelectronics, and even bio-applications. This study underscores the potential utilization of these hybrids as photoresponsive materials, for potential application in optostimulation. In this study, we examine the characteristics of covalent azobenzene-functionalized CNDs, with a particular emphasis on the impact of meta and para connectivity and the additional introduction of a glycine spacer. The CND synthesis process comprises a bottom-up microwave condensation of ethylenediamine and citric acid. Amide coupling to azobenzenes is confirmed through NMR diffusion-ordered spectroscopy and diffusion decay analysis. A comprehensive investigation is conducted into the size and optical properties of the resulting hybrids. Moreover, time-dependent density functional theory computations are employed to understand absorption spectra and charge transfer events. Furthermore, advanced optical characterisation is utilised to examine energy/charge transfer between the constituents. Finally, the switching properties, fatigue resistance, and half-life of the hybrids are studied to evaluate their performance for prospective applications like in optostimulation.