Light-enhanced liquid-phase exfoliation and current photoswitching in graphene–azobenzene composites

Abstract

Multifunctional materials can be engineered by combining multiple chemical components, each conferring a well-defined function to the ensemble. Graphene is at the centre of an ever-growing research effort due to its combination of unique properties. Here we show that the large conformational change associated with the trans–cis photochemical isomerization of alkyl-substituted azobenzenes can be used to improve the efficiency of liquid-phase exfoliation of graphite, with the photochromic molecules acting as dispersion-stabilizing agents. We also demonstrate reversible photo-modulated current in two-terminal devices based on graphene–azobenzene composites. We assign this tuneable electrical characteristics to the intercalation of the azobenzene between adjacent graphene layers and the resulting increase in the interlayer distance on (photo)switching from the linear trans-form to the bulky cis-form of the photochromes. These findings pave the way to the development of new optically controlled memories for light-assisted programming and high-sensitive photosensors.

Environmental effects on the charge transfer properties of Graphene quantum dot based interfaces

“…The system is thus split into two parts, a donor and an acceptor monomers and the coupling is then calculated considering any amount of molecular orbitals from the donor and acceptor sites, with all possible contributions (vertical and diagonal coupling terms). This software has been applied successfully in our previous studies on different interfaces …”

Functionalization of 2D Materials with Photosensitive Molecules: From Light‐Responsive Hybrid Systems to Multifunctional Devices

“…Recently Döbbelin et al proposed a new methodology to construct the hybrid system with bistable conductance states . During the liquid‐phase exfoliation of graphite, alkyl‐substituted azobenzenes were added as dispersion‐stabilizing agents to improve the exfoliation efficiency.…”

Theoretical studies on tunable electronic structures and potential applications of two‐dimensional arsenene‐based materials

“…To date, however, the exfoliation of gray arsenic into few layered arsenene still faces huge obstacles. Taking advantage of the evident conformational change of alkyl‐substituted azobenzenes (AB) during the trans – cis photochemical isomerization, the efficiency of liquid‐phase exfoliation of graphite was shown to be improved . Stimulated by this success in liquid‐phase exfoliation of graphite, a theoretical prediction has recently been presented referred to the light‐assisted exfoliation of multilayered into few‐layered or even monolayered arsenene by using AB derivatives .…”

“…Taking advantage of the evident conformational change of alkyl-substituted azobenzenes (AB) during the trans-cis photochemical isomerization, the efficiency of liquid-phase exfoliation of graphite was shown to be improved. 38 exfoliation of graphite, a theoretical prediction has recently been presented referred to the light-assisted exfoliation of multilayered into few-layered or even monolayered arsenene by using AB derivatives. 37 With exposure to light, the cis-to-trans conformational change of AB or AB-OC 10 H 21 (Figure 3b) could induce the changes of dihedral angle ( Figure 3c) and interlayer spacing ( Figure 3d).…”