The intersystem crossing from singlet state to triplet state is an important basic process of photophysics. At the same time, organic semiconductor materials with a large number of triplet states have broad application prospects in the fields of photovoltaic, room temperature phosphorescence and photodynamics. Therefore, three lines are designed and synthesized. The state of organic semiconductor materials is a hot spot in the field of materials, which has attracted the attention of scientists.
In the field of organic solar cells, the working mechanism of triplet materials has always had a different scientific view. Early opinions suggested that triplet materials are conducive to increasing the exciton migration distance, which is conducive to the improvement of the performance of solar cells; recent related research shows that Due to the existence of the triplet-triplet quenching (TTA) process, triplet materials may be detrimental to exciton migration and charge separation, and are not adapted to build high-performance organic solar cells.
In response to the basic scientific issues of the triplet, the Huanghui Research Group of the College of Materials Science and Optoelectronics, University of Chinese Academy of Sciences and the Key Laboratory of Vacuum Physics of the Chinese Academy of Sciences has taken porphyrin materials as an entry point in recent years and systematically studied the use of such triplet materials in the field of optoelectronics. Applications to explore the basic working principle of triplet materials. The researchers designed and synthesized the first n-type porphine conjugated polymer materials and constructed an excellent all-polymer organic solar cell (ACS Applied Materials & Interfaces, 2016, 8, 34620-34629). Then, random copolymerization was used to design and synthesize a series of randomly copolymerized n-type conjugated polymer materials, and a highly responsive all-polymer photodetector was constructed. (ACS Applied Materials & Interfaces, 2018, 10, 1917-1924). However, in the above research process, no significant triplet state was observed due to the limitation of the material's performance, so the working mechanism of the triplet material could not be entered. More in-depth study.
Recently, supported by the National Natural Science Foundation of China, Beijing Natural Science Foundation and the Chinese Academy of Sciences, Huang Hui research group designed and synthesized a series of tellurophene n-type organic semiconductor materials with different degrees of condensed rings. The results show that, The degree of the condensed ring has a significant effect on the physicochemical properties of the material and the performance of the solar cell. By adjusting the degree of the condensed ring, an organic solar cell with an energy conversion rate of more than 7.5% is finally achieved. Further studies show that such materials have a strong lineage Since the triplet state of this kind of material is not lower than its charge transfer (CT) state, the triplet exciton can return to the charge Metastable state and eventually separated into freely migrating electrons and holes, thus contributing to the performance improvement of the solar cell.This work was considered by reviewers as "concept novelty and significance" (conceptual novelty and importance) and published by Angew. Chem. Int. Ed. (2018, 57, 1097).
