Refreshing the solution-based LED record, Zhejiang University developed a 1.16 million nit ultra-bright perovskite LED, and the results were published in "Nature"

On the basis of controllable doping, the team developed a perovskite LED with a simple structure and set a high-brightness record for solution-based LEDs, reaching 1.16 million nits.

"Doping" is a basic concept in the field of semiconductors. The key reason why semiconductor materials are so widely used in electronic technology is that they can achieve two different conductive properties, p-type and n-type, through doping. For traditional semiconductors, through "doping", that is, the introduction of impurities into the crystal lattice, effective control of their electrical properties can be achieved.

Perovskite halide is a new type of semiconductor that exhibits excellent optoelectronic properties in solar cells, LEDs, lasers and other devices, and is easy to prepare at low cost. However, due to its complex structure and composition, how to accurately control its electrical properties is an important challenge in the field.The team accidentally discovered 4PACz. This very common material in the laboratory, due to its strong electron-withdrawing ability, when introduced as a dopant into a perovskite semiconductor, can effectively convert the originally n-type perovskite into a p-type. At the same time, after the introduction of doping, the perovskite semiconductor still maintains high fluorescence efficiency. In addition, the team also discovered n-type dopants suitable for perovskites.

Through controlled doping technologyUsing this technology, the research team successfully prepared a perovskite LED that does not contain a hole transport layer and has excellent performance. At the same time, it also shows significant advantages compared to conventional LEDs.

The p-type perovskite LED prepared by introducing 4PACz doping not only has a simple structure, but also achieves a maximum brightness of 1.16 million cd/m (1.16 million nits), an external quantum efficiency of 28.4%, and an energy conversion efficiency of 23.1%.

Xiong Wentao, a 2020 doctoral student at Zhejiang University, said, "The ultra-high brightness of these devices has refreshed the record of solution-based LEDs (including OLEDs, quantum dot LEDs and perovskite LEDs), and their energy conversion efficiency is the highest level among visible light perovskite LEDs. ”