Published on: 12-Oct-2018
Scientists have achieved a 20 percent efficiency record
in light-emitting diodes (LEDs) made of perovskite materials, comparable to
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
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