​Scientists develop record-breaking perovskite light-emitting diodes.

Published on: 12-Oct-2018

Scientists have achieved a 20 percent efficiency record in light-emitting diodes (LEDs) made of perovskite materials, comparable to conventional LEDs.


An international research team, including scientists from from NTU (Singapore), Huaqiao University (China), and the University of Toronto Canada) has achieved a new world record in the efficiency of light-emitting diodes (LEDs) made from halide perovskite materials. Halide perovskites are a class of cheap and naturally abundant materials poised to take the place of traditional semiconductors in next-generation LEDs, solar cells, and other electronic devices. The new 20 percent efficiency record for perovskite LEDs is comparable, for the first time, to the efficiency of commercially-available conventional LEDs, OLEDs or quantum dot LEDs.


Conventional LEDs, made of semiconductor materials such as gallium arsenide, are in widespread use because of their high efficiency. This efficiency, defined as the proportion of electrical power successfully converted to light, ranges from 15 to 25 percent for commercial LEDs, compared to around 2 percent for incandescent bulbs. In recent years, however, scientists have begun looking into replacing traditional semiconductors with materials known as halide perovskites.  One major appeal of perovskite-based devices is that they can be manufactured by methods such as inkjet-printing or spin coating, which are much cheaper than standard semiconductor fabrication techniques.


Writing in the October issue of the journal Nature, the team reports that by mixing in a carefully-chosen additive during the manufacturing process, many defects in the all-inorganic perovskite atomic structure can be removed. Since these defects wastefully scatter the electric current flowing in the material, removing them results in a substantial jump in the light-emission efficiency. The team found an efficiency of over 20 percent, compared to the maximum efficiencies of

12 to 14 percent reported for earlier perovskite LEDs.


"Perovskite LEDs are much cheaper to make," explains Professor Qihua Xiong of NTU's School of Physical and Mathematical Sciences, one of the lead authors of the paper.  "So the fact that we achieved an efficiency comparable to commercial LEDs is very encouraging.  It marks a step toward cheaper LEDs for use in lighting and display screens in the future."


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