AsianScientist (May 20, 2016) – Researchers in Singapore have developed a method to enhance the photoluminescence efficiency of tungsten diselenide, a two-dimensional semiconductor. Their work, published in Nature Communications, helps pave the way for the application of such semiconductors in advanced optoelectronic and photonic devices.
Tungsten diselenide is a single-molecule-thick semiconductor that is part of an emerging class of materials called transition metal dichalcogenides, which have the ability to convert light to electricity and vice versa. This quality makes them strong potential candidates for optoelectronic devices such as thin film solar cells, photodetectors, flexible logic circuits and sensors.
However, its atomically thin structure reduces its absorption and photoluminescence properties, thereby limiting its practical applications.
The team, led by Professor Andrew Wee of the Department of Physics at the National University of Singapore Faculty of Science, incorporated monolayers of tungsten diselenide onto gold substrates with nanosized trenches. This way, they successfully enhanced the nanomaterial’s photoluminescence by up to 20,000-fold.
“This is the first work to demonstrate the use of gold plasmonic nanostructures to improve the photoluminescence of tungsten diselenide, and we have managed to achieve an unprecedented enhancement of the light absorption and emission efficiency of this nanomaterial,” said first author, PhD student Ms. Wang Zhuo.
“The key to this work is the design of the gold plasmonic nanoarray templates,” said Wee. “In our system, the resonances can be tuned to be matched with the pump laser wavelength by varying the pitch of the structures. This is critical for plasmon coupling with light to achieve optimal field confinement.”
The article can be found at: Wang et al. (2016) Giant Photoluminescence Enhancement in Tungsten-Diselenide–Gold Plasmonic Hybrid Structures.
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Source: National University of Singapore.
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