Figure 2: Spectroscopic characterization of trans-to-cis isomerization and cis-to-trans relaxation.
From: Light-enhanced liquid-phase exfoliation and current photoswitching in graphene–azobenzene composites
(a) UV-ndash;visible spectra of 4-(decyloxy)azobenzene in NMP (1.62 mM) showing the disappearance of the 353-nm band and an increase of the 442-nm band for 365-nm irradiation. The solid black line corresponds to the parent trans-4-(decyloxy)azobenzene spectrum, the red line represents a typical spectrum of a solution irradiated with UV light (cis-4-(decyloxy)azobenzene), whereas the black dashed line corresponds to a cis-4-(decyloxy)azobenzene solution irradiated with visible light (thus re-transformed into trans-4-(decyloxy)azobenzene). (b) Conversion percentage from trans to cis as a function of UV irradiation time at 20 and 40 °C. (c) First-order kinetic plots and rate constants (ktrans–cis) for trans-to-cis isomerization at 20 and 40 °C. (d) Conversion percentage from cis to trans as a function of time at 20 and 40 °C. (e) First-order kinetic plots and rate constants (kcis–trans) for the cis-to-trans relaxation at 20 and 40 °C. (b–e) Reference samples prepared without sonication: blue (20 °C) and red (40 °C); sonicated samples: green (20 °C) and orange (40 °C).
