China's near-infrared perovskite LED light leads the world

The team led by Professor Huang Wei, a professor of the Institute of Flexible Electronics of Northwestern Polytechnical University, and Professor Wang Weipu, an academician of the Chinese Academy of Sciences and the Executive Vice President of the Advanced Materials Research Institute of Nanjing University of Technology, used the low-temperature solution method to design a perovskite luminescent layer. A new idea was put forward to increase the external quantum efficiency of near-infrared perovskite LEDs to 20.7%, which set a new world record. The relevant research results were published in Nature on October 11.

LED is a kind of semiconductor electronic component that can convert electric energy into light energy. It has the characteristics of energy saving, environmental protection, safety and high brightness. It has been widely used in daily life and production. The perovskite light-emitting diodes that have emerged in recent years have both The advantages of inorganic LEDs and organic light-emitting diodes (OLEDs) have broad application prospects in low-energy, high-brightness, large-size display and illumination. In 2016, the research team proposed the regulation of perovskite dimensions to create perovskite light-emitting diodes ( LED) efficiency record.

For many scientists who have been engaged in perovskite LED research for a long time, only the perovskite film with high coverage and high porosity and no obvious holes is the basis for realizing high-efficiency devices. The research team is in Nature. The research paper entitled 'Perovski-based light-emitting diodes based on spontaneous submicron structure' not only breaks this view, but also reports the world's highest external quantum efficiency of perovskite LEDs. Professor Wang Jianpu said that they It is found that when the perovskite grains are like mahjong tiles, which are not connected to each other and irregularly distributed on the surface of the substrate, a near-infrared perovskite light-emitting diode with an external quantum efficiency of 20.7% can be obtained, which is obtained with international counterparts. % external quantum efficiency is increased by nearly 8 percentage points, the device irradiance reaches 390 W sr-1 m-2, and the efficiency is reduced by half after continuous operation for 20 hours at a current density of 100 mA cm-2. Performance far exceeds the current popular OLEDs with similar illumination bands.

According to Academician Huang Wei, the team also cooperated with Professor Tian He and Professor Dai Dao Zinc of Zhejiang University to find that this perovskite luminescent layer is composed of dispersed perovskite crystal grains and embedded in the crystal grains. The refractive index is composed of an organic insulating layer, and the structure can further form a high and low undulating pleat structure of the device top electrode, thereby effectively improving the light extraction efficiency of the device. This achievement has important theoretical significance for the development and application of the perovskite LED. And practical significance, to provide a new way of thinking and ways to further promote the industrialization of perovskite LED.