Perovskite-based LED luminous efficiency is set to record in the field of lighting and other fields
2019-04-30

Original title: close to 100%! Perovskite-based LED luminous efficiency record


钙钛矿基LED发光效率创纪录 有望应用于照明等领域

Scientists integrated the perovskite layer into the LED. Image source: Cambridge University, UK official website


Science and Technology Daily, Beijing, November 8 (Reporter Liu Xia) According to a recent report by the University of Cambridge, the university's scientists integrated the perovskite layer into a light-emitting diode (LED), and the internal luminous efficiency of the product is close to a record 100%. It is comparable to the best organic LEDs (OLEDs) and is expected to be used in display, lighting, communications and next-generation solar cells in the future.


Compared to OLEDs widely used in high-end consumer electronics, perovskite-based LEDs are less expensive to manufacture and emit light with high color purity. Although scientists have previously developed perovskite-based LEDs, the resulting products are less efficient at converting electricity into light than conventional OLEDs. The team of Professor Richard Fried, of the University of Cambridge's Cavendish Laboratory, has developed a hybrid perovskite-based LED whose loss of perovskite layer caused by tiny defects in the internal crystal structure limits their luminous efficiency. .


Now, the team has demonstrated through new research that allowing perovskites to form a composite layer with polymers can achieve higher luminous efficiency, close to the theoretical efficiency limit of thin film OLEDs. The findings are published in the latest issue of Nature Photonics.


The perovskite-polymer composite layer in the LED device is made of a two-dimensional, three-dimensional perovskite and an insulating polymer. When the ultrafast laser is illuminated on the structure, the energy carrying energy moves from the two-dimensional region to the three-dimensional region in one trillionth of a second. Then, the 'respectively' charges in the three-dimensional region are effectively recombined and illuminated.


Dr. Di David, one of the authors of the paper, explained: “The energy transfer from the two-dimensional region to the three-dimensional region occurs very quickly, and the charge in the three-dimensional region is isolated from the defects of the polymer. These mechanisms can prevent defects. 'Disorder' to prevent energy loss. This is the first time scientists have achieved this on perovskite-based products.'


Although perovskite-based LEDs have begun to compete with OLEDs in terms of efficiency, they are currently in poor stability and cannot be used in consumer electronics for the time being. When a perovskite-based LED was first introduced, its lifetime was only a few seconds. The half-life of perovskite-based LEDs in the new study is about 50 hours. Although it has improved a lot, it is still far from the life expectancy required for commercial applications. To achieve this, a wide range of industrial development plans are needed. Di David said: 'Understanding the degradation mechanism of LEDs is the key to future improvements.'


Source: Technology Daily