Molybdenite diodes that can emit light or absorb it to produce electricity

April 25, 2014 by Sarah Perrin
The magic of Molybdenite: solar cells and light-emitting diodes
Credit: EPFL

After using it to develop a computer chip, flash memory device and photographic sensor, EPFL scientists have once again tapped into the electronic potential of molybdenite (MoS2) by creating diodes that can emit light or absorb it to produce electricity.

Molybdenite has a few surprises still up its sleeve. After having used it to build an , a flash memory device and a photographic sensor, EPFL professor Andras Kis and his team in the Laboratory of Nanoscale Electronics and Structures (LANES) is continuing his study of this promising semi-conductor. In research recently published in the journal ACS Nano, they have demonstrated the possibility of creating light-emitting diodes and .

The scientists built several prototypes of diodes – in which voltage flows in only one direction – made up of a layer of superposed on a layer of silicon. At the interface, each electron emitted by the MoS2 combines with a "hole" – a space left vacant by an electron – in the silicon. The two elements lose their respective energies, which then transforms into photons. "This light production is caused by the specific properties of molybdenite," explains Kis. "Other semi-conductors would tend to transform this energy into heat."

Even better, by inversing the device, electricity can be produced from light. The principle is the same: when a photon reaches the molybdenite, it ejects an electron, thus creating a "hole" and generating voltage. "The diode works like a solar cell," says Kis. "Our tests showed an efficiency of more than 4%. Molybdenite and silicon are truly working in tandem here. The MoS2 is more efficient in the visible wavelengths of the spectrum, and silicon works more in the infrared range, thus the two working together cover the largest possible spectral range."

Credit: EPFL

The scientists want to study the possibility of building electroluminescent diodes and bulbs. This discovery could, above all, reduce the dissipation of energy in electronic devices such as microprocessors, by replacing copper wires used for transmitting data with light-emitters.

Explore further: New transistors: An alternative to silicon and better than graphene

Related Stories

First molybdenite microchip

December 5, 2011

( -- Molybdenite, a new and very promising material, can surpass the physical limits of silicon. EPFL scientists have proven this by making the first molybdenite microchip, with smaller and more energy efficient ...

Fantastic flash memory combines graphene and molybdenite

March 19, 2013

Swiss scientists have combined two materials with advantageous electronic properties—graphene and molybdenite—into a flash memory prototype that is very promising in terms of performance, size, flexibility and energy ...

An ultrasensitive molybdenum-based image sensor

June 12, 2013

A new material has the potential to improve the sensitivity of photographic image sensors by a factor of five. In 2011, an EPFL team led by Andras Kis discovered the amazing semi-conducting properties of molybdenite (MoS2), ...

Researchers develop first single-molecule LED

February 3, 2014

The ultimate challenge in the race to miniaturize light emitting diodes (LED) has now been met: a team led by the Institut de Physique et de Chimie des Matériaux de Strasbourg has developed the first ever single-molecule ...

Recommended for you

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.