By northwestern polytechnical university flexible electronics research institute's chief scientist, professor of Chinese academy of sciences stevie hoang and the executive vice President of nanjing university of technology institute of advanced materials Wang Jianpu professor team LED by using low temperature solution method, recently on perovskite light-emitting layer design puts forward the new way of thinking, near-infrared perovskite LED external quantum efficiency is raised to 20. 7%, a new world record, was published in the journal Nature on October 11th.
LED is a kind of semiconductor electronic device which can convert electric energy into light energy. It is characterized by energy saving, environmental protection, safety and high brightness. It has been widely used in daily life and production. Perovskite light-emitting diodes, which have both advantages of inorganic LED and organic light-emitting diode (OLED) in recent years, have broad application prospects in the fields of low energy consumption, high brightness, large size display and lighting. In 2016, the research team proposed that perovskite dimension regulation creates perovskite light-emitting diode (LED) efficiency record.
For many scientists who have been working on perovskite LED research for a long time, only the flat perovskite thin film with high coverage and no obvious holes is the basis for the realization of efficient devices. The team's paper, titled "perovskite light-emitting diodes based on the spontaneous formation of submicron structures," in nature, not only breaks this idea, but also reports the world's highest external quantum efficiency of perovskite leds. Professor wang said they found that when perovskite grains were like mah-jongg tiles, separated from each other and distributed irregularly on the substrate's surface, an external quantum efficiency of 20 could be obtained. 7% of the near infrared perovskite light-emitting diodes (leds), compared with 13% of the international peers to obtain external quantum efficiency, increased by nearly 8%, device irradiance sr - 390 W 1 m - 2, and under the current density of 100 mA cm - 2 continuous work efficiency to reduce half after 20 hours, performance far exceeds the current hot glowing band OLED.
According to stevie hoang academician, the team also with zhejiang university professor Tian He, zinc professor team, found that the perovskite light-emitting layer is composed of scattered perovskite between grain size and embedded in the grain size of low refractive index of organic insulating layer, and the structure can be further device makes the ups and downs of the top electrode formation fold structure, thus effectively improve the device of the optical efficiency. This achievement has important theoretical and practical significance for the development and application of perovskite LED, and provides a new idea and approach to further promote the industrialization development of perovskite LED.