Harbin Institute of Technology breaks through global problems: "unlocking" graphene light-induced precise functionalization
As the world’s first true two-dimensional material, graphene is not only the thinnest and hardest two-dimensional material, but also has excellent electrical conductivity, thermal conductivity, optical properties and stability. It is used in aerospace, solar energy, and transparency. It is widely used in the fields of touch screens, electronic devices, sensor detection, biomedicine, wearable devices, and high-performance composite materials.
However, the zero band gap of graphene limits its practical application possibilities. Although in the past ten years, there have been a variety of methods for graphene functionalization to open the band gap, such as doping foreign atoms, modifying nanoparticles, manufacturing nanostructured graphene, surface adsorption, etc., long-range ordering and atomic level precision Modulating the local hybridization of graphene is still a worldwide problem.
This work uses BCM molecules with maleimide and dicarboxylic acid groups to form a full-covered two-dimensional extended ordered network on the surface of a single layer of graphene with intermolecular double hydrogen bonds, which is exposed to ultra-high vacuum by ultraviolet radiation Under the conditions, the photocycloaddition reaction between the molecular network and the graphene base surface is triggered.
The effect of photocycloaddition reaction on the absorption vibration and band structure of graphene. Photo courtesy of Harbin Institute of Technology
The photoreaction can precisely modulate the local hybridization mode of graphene, change the electronic structure of graphene, and effectively introduce a band gap. Different from the reaction triggering methods used by predecessors such as long-term immersion, heating, electric pulse and probe pressure, photoreaction not only provides a practical solution for high endothermic reactions, but also has simplicity, remote controllability, and The compatibility of other optical-related technologies (such as photolithography) is more conducive to practical applications in electronics and optoelectronic devices.
As the first example of the reaction of graphene with molecular networks, this work unlocks an efficient way to accurately and orderly modulate the electronic structure of graphene, which is of great significance for the further development of light-induced surface synthesis reactions. At the same time, this precise regulation of local hybridization and the long-range order of graphene after functionalization paved the way for the development of graphene-based cutting-edge nanoelectronic and optoelectronic devices.