In recent years, with the vigorous development of graphite olefin industry, a new simple two-dimensional atomic crystal material-black phosphorus has been discovered. Similar to graphite ore, black phosphorus has many excellent characteristics, so it is called "comparable graphite ore". Dream material? . Zhang Han revealed that the research and application of black phosphorus has just begun, and its nonlinear optical characteristics have been confirmed by many units at home and abroad, and it has been applied to the generation of ultrafast lasers. It is foreseeable that in the near future, it will become? The second graphene? .
In May this year, Zhang Han's team found that black phosphorus has broadband saturable light absorption characteristics, and the wavelength range can cover visible light to mid-infrared band. In the laser field, devices with saturable absorption characteristics are the key to construct ultrashort pulse lasers, and the discovery of black phosphorus provides the possibility for mid-infrared ultrafast optical devices. This discovery was published in the international journal Advanced Functional Materials.
Zhang Han said that research shows that graphite olefin is a semi-metallic semiconductor material with no band gap, which has ultra-high electron mobility and broadband light absorption characteristics. However, the band structure without band gap limits the application and development of graphene in the photoelectric field. The biggest feature of black phosphorus is that it has a direct band gap that can change with the number of layers, which just solves the problem that plagues graphite olefins.
As early as 20 14, team Zhang of Fudan University realized the application of high-speed field effect transistors with several layers of black phosphorus, which opened the prelude to the extensive research on black phosphorus.
The application of black phosphorus is not limited to the photoelectric field. Phosphorus is an essential element for human body and has advantages in biomedical field. Therefore, in cooperation with Yu Xuefeng, researcher of Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, and Professor Zhu of City University of Hong Kong, a new type of ultra-small black phosphorus quantum dots was successfully developed and applied to the treatment of tumors as a photothermal preparation. This discovery has been published in the German journal Applied Chemistry.