Nanjing University has made important progress in the field of high-efficiency and stable white LED research

- Mar 11, 2021-

The invention of the blue light-emitting diode (LED) promoted the development of contemporary lighting and display industries and was awarded the 2014 Nobel Prize in Physics. Compared with traditional incandescent lamps, fluorescent lamps and high-pressure gas discharge lamps, solid white LEDs, which enjoy the reputation of "the fourth generation of lighting sources", have the advantages of high luminous efficiency, energy saving and environmental protection, long life and safety and reliability. They are considered to be the 21st century. A new generation of environmentally friendly and energy-saving light sources.

However, at present, the main way to realize white light LED lighting is to use blue LED to excite the rare earth luminescent materials with fluorescence, and then produce white light after mixing red, green and blue. Rare earth luminescent materials have the spectral characteristics of 5d-4f and 4f-4f. Because of their small light absorption cross-section and low molar extinction coefficient, they often bring about the problem of "blue light overflow" in white light illumination and display backlight applications, causing consumers, especially It is the severe myopia and macular degeneration of the adolescents, which has caused widespread concern in the whole society.

In recent years, as a new type of luminescent material, lead halide perovskite has the characteristics of adjustable fluorescence spectrum, narrow half-value width, high fluorescence quantum yield, high defect tolerance, and simple liquid phase synthesis and low cost. , Light-emitting diodes and display devices have great potential. However, its ionic properties (decomposition with light, heat, water, and oxygen) and lead toxicity limit its practical application. Therefore, it is of great significance to find an environmentally friendly, stable and efficient perovskite material that can be practically applied to LEDs.

The team of Professor Zhengtao Deng from the School of Modern Engineering and Applied Science of Nanjing University has been committed to the basic research and industrial application of new phosphors for many years. Especially in the direction of white light LEDs and wide color gamut display devices, a series of progress has been made in the performance improvement and stability of luminescent materials in response to the bottleneck problem of luminescent materials in practical applications, such as: Angew. Chem., Int. Ed . 2020, 59, 7738; Mater. Adv. 2021, 2, 1320; Chem. Commun. 2021, DOI: 10.1039/D0CC08253H; J. Mater. Chem. C 2021 DIO: 10.1039/D0TC05685E.