We need to learn a new phrase. Graphene Based Heterostructures.
This was an obvious promise of graphene research but it turns out to
be unexpectedly way more accessible than anyone imagined.
The rapid evolution of thin structures has now begun and it will
dominate all our lives. Most certainly, a high yield solar elegy
protocol will be one of the first obvious applications. Most though,
I would like to see thin skinned batteries and thin skinned coolants.
Both are difficult in three dimensional configurations but may now
become surprising.
Both will be central to the future development of the magnetic field
exclusion vessel.
May 2, 2013 —
Combining wonder material graphene with other stunning one-atom thick
materials could create the next generation of solar cells and
optoelectronic devices, scientists have revealed.
University of
Manchester and National University of Singapore researchers have
shown how building multi-layered heterostructures in a
three-dimensional stack can produce an exciting physical phenomenon
exploring new electronic devices.
The breakthrough,
published in Science, could lead to electric energy that runs entire
buildings generated by sunlight absorbed by its exposed walls; the
energy can be used at will to change the transparency and
reflectivity of fixtures and windows depending on environmental
conditions, such as temperature and brightness.
The isolation of
graphene, by University of Manchester Nobel Laureates Professor Andre
Geim and Professor Kostya Novoselov in 2004, led to the discovery of
the whole new family of one-atom-thick materials.
Graphene is the
world's thinnest, strongest and most conductive material, and has the
potential to revolutionise a huge number of diverse applications;
from smartphones and ultrafast broadband to drug delivery and
computer chips. The isolation of graphene also led to the discovery
of a whole new family of one-atom-thick materials.
Collectively, such 2D
crystals demonstrate a vast range of superlative properties: from
conductive to insulating, from opaque to transparent. Every new
layer in these stacks adds exciting new functions, so the
heterostructures are ideal for creating novel, multifunctional
devices.
One plus one is
greater than two -- the combinations of 2D crystals allow researchers
to achieve functionality not available from any of the individual
materials.
The Manchester and
Singapore researchers expanded the functionality of these
heterostructures to optoelectronics and photonics. By combining
graphene with monolayers of transition metal dichalcogenides (TMDC),
the researchers were able to created extremely sensitive and
efficient photovoltaic devices. Such devices could potentially be
used as ultrasensitive photodetectors or very efficient solar cells.
In these devices,
layers of TMDC were sandwiched between two layers of graphene,
combining the exciting properties of both 2D crystals. TMDC layers
act as very efficient light absorbers and graphene as a transparent
conductive layer. This allows for further integration of such
photovoltaic devices into more complex, more multifunctional
heterostructures.
Professor Novoselov
said: "We are excited about the new physics and new
opportunities which are brought to us by heterostructures based on 2D
atomic crystals. The library of available 2D crystals is already
quite rich, covering a large parameter space.
"Such photoactive
heterostructures add yet new possibilities, and pave the road for new
types of experiments. As we create more and more complex
heterostructures, so the functionalities of the devices will become
richer, entering the realm of multifunctional devices."
University of
Manchester researcher and lead author Dr Liam Britnell added: "It
was impressive how quickly we passed from the idea of such
photosensitive heterostructures to the working device. It worked
practically from the very beginning and even the most unoptimised
structures showed very respectable characteristics"
Professor Antonio
Castro Neto, Director of the Graphene Research Centre at the National
University of Singapore added: "We were able to identify the
ideal combination of materials: very photosensitive TMDC and
optically transparent and conductive graphene, which collectively
create a very efficient photovoltaic device.
"We are sure that
as we research more into the area of 2D atomic crystals we will be
able to identify more of such complimentary materials and create more
complex heterostructures with multiple functionalities. This is
really an open field and we will explore it."
Dr Cinzia Casiraghi,
from The University of Manchester, added: "Photosensitive
heterostructures would open a way for other heterostructures with new
functionalities. Also, in future we plan for cheaper and more
efficient heterostructure for photovoltaic applications."
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