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In the conversion of light energy into electric energy, all-polymer solar cells use a blend of a p-type polymer semiconductor (donor) and an n-type polymer semiconductor (receptor) as an active layer, as compared with conventional inorganic solar cells. The outstanding advantages of flexibility, low cost, and light weight have become one of the important directions for solar cell research. However, the number and type of n-type polymer semiconductors are much smaller than those of p-type polymer semiconductors. Therefore, the development of n-type polymer semiconductor materials is the core of the development of all-polymer solar cells.
Liu Jun Group, State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, proposed the use of boron-nitrogen coordination bonds (Bâ†N) to reduce LUMO/HOMO energy levels of conjugated polymers and to develop n-type polymers. Semiconductor strategies, and the development of two types of boron-nitrogen coordination bond n-type polymer semiconductor acceptor material, its all-polymer solar cell device efficiency and classical imide n-type polymer semiconductor similar.
The research group first elucidated the basic principle of boron-nitrogen coordination bonds to reduce the LUMO/HOMO energy level of conjugated polymers. For the first time, boron-nitrogen coordination bonds were introduced into the molecular design of n-type polymer semiconductors (Angew. Chem. Int. Ed., 2015, 54, 3648). Further, two molecular design methods for designing n-type polymer semiconductor acceptor materials using boron-nitrogen coordination bonds are proposed: First, in the repeating units of conjugated polymers, a boron-nitrogen coordination bond is used to replace carbon-carbon covalent bonds. , to reduce the LUMO/HOMO level of the conjugated polymer by 0.5–0.6 eV at the same time, and to convert the common p-type polymer semiconductor donor material into an n-type polymer semiconductor acceptor material (Angew. Chem. Int. Ed. 2016, 55, 5313); Secondly, a novel electron-deficient unit based on boron-nitrogen coordination bonds, bis-boron-nitrogen-bridged bipyridyl, was designed first, and then used to construct n-type polymer semiconductor acceptor materials (Angew. Chem. Int Ed., 2016, 55, 1436).
Studies have shown that boron-nitrogen coordination bonds n-type polymer semiconductors have the characteristics of LUMO orbital delocalization and LUMO energy levels are adjustable (Chem. Sci., 2016, 7, 6197). Based on this unique electronic structure, a photonic energy loss of 0.51 eV was achieved while achieving the full polymer solar cell device efficiency of 6%, which exceeded the limit of the 0.6 eV minimum photon energy loss in conventional organic solar cells, and is also known in the literature. The lowest value (Adv. Mater., 2016, 28, 6504).
The work was funded by the Ministry of Science and Technology's "973" project, the International Natural Science Foundation, the "Yang Thousand Talent Plan" of the Central Organization Department, and the CAS's pilot project.
Pneumatic valve is a kind of valve controlled by air pressure, which is widely used in industrial automation control system. Its main applications include the following aspects:
1. Fluid control: pneumatic valve can be used to control the flow and direction of liquid or gas, such as controlling the flow in the pipeline, exhaust gas emission, etc.
2. Pressure control: pneumatic valve can be used to control the pressure of fluid, such as controlling the pressure of compressed air, regulating the pressure in the hydraulic system, etc.
3. Temperature control: pneumatic valve can be used to control the temperature of fluid, such as the temperature of heating or cooling system.
4. Automatic control: pneumatic valve can be linked with sensors, PLC and other equipment to realize automatic control, such as automatic production lines, robots, etc.
5. Safety control: pneumatic valve can be used for safety control, such as controlling emergency stop, preventing overload, etc.
In general, pneumatic valve plays an important role in industrial automation control system, which can improve production efficiency, reduce costs, and ensure safety.
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