Recently, the Huang Chunhui project of the School of Chemistry and Molecular Engineering of Peking University has combined into two df transition rare earth cerium(III) complexes Ce-1 and Ce-2 with nanosecond short excited state lifetimes, which emit dark blue and Ce-2 respectively under ultraviolet excitation Sky blue light and photoluminescence quantum yields both exceed 90%.
After optimization, the two materials have achieved high-efficiency blue light emission in OLED, which proved for the first time that the cerium(III) complex has 100% exciton utilization rate in OLED.
In addition, compared to traditional phosphorescent iridium (III) complex devices with similar emission colors, the working stability of devices based on cerium (III) complexes is improved by nearly 70 times.
Image source: Peking University News Network
According to the Peking University News Network, considering that the cerium (III) complex also has a tunable emission spectrum (the d orbital is significantly affected by the ligand field) and lower raw material costs (the content of cerium in the crust is nearly 60000 that of iridium). Times higher than copper), this type of luminescent material is not only expected to solve the problems of high-efficiency blue OLED in practical applications, but also has the potential to become a new generation of luminescent materials for OLED full-color display and lighting. This work is of great significance for realizing the high-value utilization of rare earth resources in my country and developing OLED light-emitting materials with independent intellectual property rights.
Currently, the above-mentioned deep blue OLED work is published in Light: Science & Applications, and the sky blue OLED work is published in National Science Review. Related work has applied for a patent "Electroluminescent materials and devices based on d-f transition" and obtained authorization.
In addition, the above research was funded by the National Key Research and Development Program, Beijing Natural Science Foundation, and China Postdoctoral Fund.