ENGINEERING TECHNOLOGY

“Nature”: The near-infrared perovskite LED with “optimal” comprehensive performance came out


Perovskite materials have shown great application potential in the field of optoelectronic devices such as light-emitting diodes (LEDs), solar cells, photodetectors and lasers due to their excellent photoelectric properties.

Recently, Professor Cui Linsong’s research group of the University of Science and Technology of China and the team of Professor Neil C. Greenham of the University of Cambridge have realized a near-infrared perovskite light-emitting diode with high brightness, high efficiency and high stability, the maximum external quantum efficiency of the device is as high as 23.8%, the maximum radiation brightness reaches 663 watts / (sphere degree · square meter), the device life expectancy can reach more than 50,000 hours, and the device performance has reached the international leading level, solving important problems in this field. On March 16, the relevant research results were published in the journal Nature.

Group photo of members of Professor Cui Linsong’s research group Photo by Zhou Xinyu

Cui Linsong introduced, “Luminous brightness, external quantum efficiency and stability are the key indicators that determine the commercial application of perovskite LEDs. However, most of the NIR perovskite LEDs reported so far always have the contradiction that the efficiency is too low at high brightness and the brightness is too low at high efficiency. How to maintain high efficiency and stability while high brightness is an urgent problem to be solved in the field of perovskite LED, and it is also a key technical bottleneck that restricts its commercial application. ”

In this study, the research team designed and developed a multifunctional molecular stabilizer 2-(4-methylsulfonylphenyl)ethanamine (MSPE), which is used to precisely regulate the photoelectric properties, crystal structure and morphological properties of perovskite materials, and greatly improve the efficiency and stability of perovskite LEDs at high brightness. On the one hand, MSPE interacts with the components in perovskite through hydrogen bonds and coordination bonds, effectively regulates the crystallization growth process of perovskite, improves the crystallinity of the film and the regularity of the grain, and realizes the effective passivation of perovskite surface/interface defects, greatly improving the luminous efficiency and luminescence uniformity of perovskite film. On the other hand, MSPE molecules induce the formation of self-assembly structures through hydrogen bonding, which inhibits the formation of low-energy states at the transport layer interface and eliminates the quenching of perovskite materials by the transport layer interface.

Thanks to the synergistic passivation effect of MSPE on the perovskite and transport layer interface, the researchers achieved near-infrared perovskite LEDs with high brightness, high efficiency and high stability. The peak external quantum efficiency of the device is as high as 23.8%, and at a current density of 1000 mA/square centimeter, the external quantum efficiency of the device can still exceed 10%, showing ultra-high efficiency stability. In the pulse working mode, when the current density is as high as 4000 mA / square centimeter, the external quantum efficiency of the device is still more than 16%, and the radiation brightness reaches 3200 watts / (sphere degree · square meter), the life expectancy of the device can reach more than 50,000 hours, and the radiation brightness and stability are at the leading level in the current near-infrared perovskite LED with an external quantum efficiency of more than 20%.

Cui Linsong said: “At high brightness, achieving efficient and stable perovskite LEDs is a key step towards commercialization, and it is expected to further realize perovskite electric pump lasers in the future. ”

The reviewers commented on the work: “The team designed and developed a novel multifunctional molecular stabilizer to prepare near-infrared perovskite LEDs with the best comprehensive performance ever, and these results are impressive and have aroused great interest among researchers in the field.” (Source: Wang Min, China Science News)

Related paper information:https://doi.org/10.1038/s41586-023-05792-4



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