Pang Wenhui, Xue Jijun, Pang Hua
National Joint Engineering Laboratory of optical conversion materials and technology, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China.
Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China.
Sci Rep. 2019 Mar 26;9(1):5224. doi: 10.1038/s41598-019-41563-w.
Incorporating photochromic chromophores into polymer composites provides the possibility of a reversible photoswitch of the intrinsic properties of these materials. In this paper we report a route to attach azobenzene (AZO) moiety covalently to graphene oxide (GO) to create chromophore/graphene oxide (AZO-GO) hybrid, in which GO is both part of the chromophore and the template. Due to the high grafting density of AZO moiety and the low mass of the novel structure, the hybrid is a potential solar thermal storage material with high energy density of about 240 Wh·kg. It is found that C-H···π interaction between the cis-AZO chromophores and the aromatic rings of the substrate induces collective electronic modifications of GO at critical percentage of cis-isomers and reduce the thermal barrier of π-π* transition of the chromophores directly, which results in two sections of first-order reactions during the photoisomerization of trans- to cis-hybrid and also thermally stabilizes the cis-hybrid. Our findings demonstrate that high-performance AZO-GO hybrid can be manipulated by optimizing intermolecular nonbonding interactions.
将光致变色发色团引入聚合物复合材料中，为这些材料固有特性的可逆光开关提供了可能性。在本文中，我们报道了一种将偶氮苯（AZO）部分共价连接到氧化石墨烯（GO）上以制备发色团/氧化石墨烯（AZO-GO）杂化物的方法，其中GO既是发色团的一部分又是模板。由于AZO部分的高接枝密度和新结构的低质量，该杂化物是一种潜在的太阳能储热材料，其能量密度约为240 Wh·kg，较高。研究发现，顺式-AZO发色团与底物芳香环之间的C-H···π相互作用在顺式异构体的临界百分比下诱导了GO的集体电子修饰，并直接降低了发色团π-π*跃迁的热垒，这导致了反式-顺式杂化物光异构化过程中的两段一级反应，同时也使顺式杂化物热稳定。我们的研究结果表明，可以通过优化分子间非键相互作用来调控高性能的AZO-GO杂化物。
