Professor Li Feng's team at the State Key Laboratory of Supramolecular Structure and Materials, School of Chemistry, Jilin University used organic light-emitting free radical materials to prepare organic light-emitting diodes, which achieved a quantum efficiency close to 100% and solved the problem of low luminous efficiency of traditional fluorescent light-emitting materials. The achievement was published in 'Nature' with Jilin University as the first completion unit.

Light-emitting devices are key components in the field of display and lighting. Compared with traditional light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs) have the advantages of high contrast, ultra-thin and flexible, and have huge market value in the field of display and lighting And application prospects. The traditional organic light-emitting diode is theoretically only 25% of its energy can be used to emit light. How to convert most of the remaining energy into photon light has been a hot and difficult point in the research field for nearly 30 years.

The research team found that organic light-emitting free radical materials with unique single-electron structures only generate doublet excitons when energized. In theory, 100% of doublet excitons can be used to emit light. Using organic light-emitting radical materials to prepare organic light-emitting diodes can solve the problem of low luminous efficiency of traditional organic light-emitting diodes. Through continuous improvement of materials and device structures, the team has developed free radical luminescent materials and light-emitting devices with high luminous efficiency.

Li Feng introduced that the current light-emitting materials used in organic light-emitting diodes are usually fluorescent and phosphorescent materials, but the former has limited luminous efficiency, and the latter requires heavy metals with scarce resources, resulting in increased costs. In contrast, organic free radical materials are cheap organic compounds, which reduce costs after achieving maximum electrical-to-optical conversion efficiency.

The research was supported by the National Natural Science Foundation of China, the Key R & D Program and the 973 Program of the Ministry of Science and Technology, the Visiting Scholars Program of the National Council for Studying Abroad, and the Peiying Engineering Program of Jilin University.