Recently, Jiang Jun, a research group led by Luo Yi, a professor at the National Science Research Center for Microscale Materials Science at the University of Science and Technology of China, put forward the first organic molecular solar cell design with an adaptive switch by first-principles calculations. Cost, efficiency, adaptability.
Although solar cells based on organic molecules have many advantages such as wide sources of materials, low cost, simple process, good flexibility, easy mass production, light and soft, easy to carry, biodegradable and environmental pollution, etc., The photoelectric conversion efficiency is not high, compared with the inorganic semiconductor solar cells is still a big gap.This is because the light absorbed by organic molecules, although from the donor moiety to the charge transfer occurs, but the organic molecules contained The mobility of atoms is relatively low, and energetic excited electrons are often trapped in the same small molecule, which makes it easy to recombine the electrons and holes that have not been completely separated, greatly reducing the final photoelectric conversion efficiency.
Jiang Jun research group has long been committed to the photoelectric functional molecules and photocatalytic system design and simulation of the field, focusing on the key motive force of the electronic movement, based on first-principles simulation of structural design to regulate the evolution of electrons after being excited by light. In the second study, azobenzene, an optical switch molecule, was inserted into a typical donor-acceptor system (terpyridylplatinum complex) to form a donor-optical switch-acceptor system.Firstly, The molecule has a planar conjugated configuration that absorbs visible light and produces excited electrons that are rapidly transferred from azobenzene and donors to lower energy levels (about 2 picoseconds); electrons that lose electrons The cis-trans isomerization barrier of azobenzene molecules will be reduced, and the transition from trans to cis spontaneously occurs on the order of picosecond-nanosecond. The molecular configuration transformation leads to the conjugation of the system Vandalism, conductivity is also greatly reduced, the energy of the acceptor excited by the electron can not return azobenzene and donor, so the electron and hole were stored in the receptor and donor, respectively, to achieve efficient charge separation ( Excited state life is micro Order); when the excited electron is consumed (into the electrode), the molecule returns to the ground state, the azobenzene is still in the cis configuration, the cis-molecule can absorb visible light back due to its own characteristics To the trans configuration and begin the next round of cycling.
The system inhibits the charge recombination process in organic solar cells and achieves efficient charge separation and automatic switch of molecular conductivity and is the first organic solar cell design with adaptive switchs.In addition, the donor-photo-switch-acceptor system It is not limited to azobenzene and terpyridine platinum complex molecules, but other optical switch molecules and donor-acceptor systems can also be used in this complex system. This design uses organic small molecules as materials to solve the problem of organic solar energy In the battery, charge recombination and conductivity can not be switched easily, and research ideas are provided for the low-cost and easy synthesis of organic molecular systems for large-scale applications in solar cells and photocatalysis.
Relevant research results published in the "Physical Chemistry Letters", doctoral student Wu Ziyue, Dr. Cui Peng, Zhang Guozhen co-lead author, Jiang Jun for the Corresponding author .This research has been the national key basic research and development program of young scientists project, the national nature Science Fund, Chinese Academy of Sciences strategic pilot science and technology funding.
