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.

Nature Communications 7, Article number: 11090 doi:10.1038/ncomms11090

http://www.nature.com/ncomms/2016/160407/ncomms11090/full/ncomms11090.html

多功能材料可以通过将多种化学组分结合起来获得，每种材料表现出特定的功能。石墨烯是当前科学界研究的焦点，它具有许多独特的性质。Dobbelin等人发现，烷基偶氮苯分子在不同光照下会有巨大的构型变化，这一性质可以提高液相剥离石墨的效率，而且它还可以作为分散稳定剂。此外，他们还发现，基于石墨烯-偶氮苯复合物制备的双端器件，会出现可逆的光调制电流现象。他们认为出现这种现象的原因是，偶氮苯在不同的光照条件下会呈现出顺反异构结构，改变了相邻石墨烯层间的间距。（新材料在线）