The
Novel Devices for Light Control Based on
Suspended Semiconductor Nanocrystals and
Nanostructures
Amro Dyab (PRDA, Chemistry), K.T. Lai
(PDRA, Engineering), Igor Itskevich (Engineering) and
Vesselin N. Paunov
(Chemistry)
Sponsors: EPSRC Duration: April 2006 to March 2008
Suspensions
of colloid particles in liquid solvents are a promising tool for light control.
When subjected to a strong electric field, colloidal suspensions form chains of
particles between the electrodes as a result of the electric polarisation of
the colloid particles in the solution and their orientational
interaction with the external electric field. The interaction between the
induced electric dipoles of the polarised particles leads to the particle
aggregation in anisotropic structures (chains) which changes the optical
properties of the suspension between the electrodes. For example, Suspended
Particle Devices (SPDs) based on electric field
induced chaining of sub-micrometer particles suspended in mineral oil have
already found applications in “smart glass” technologies which are commercially
available and will soon make blinds and curtains look obsolete. Such devices
can be used as light valves activated by the controlled aggregation of
particles upon application of an electric field. A common problem in such SPDs
is the relatively high operating voltage necessary to maintain the particle
polarisation which determines their practical applicability. An advance in this
area which we suggest in our proposal is to fabricate and use nanoparticles of
permanent electric dipolar moment which would allow the operating voltages and
power consumption of such SPDs to be lowered
dramatically.
The
project will allow large-scale inexpensive fabrication of semiconductor
nanoparticles with anisotropic interactions and colloidal liquid crystals based
on these particles. Beneficiaries of the project will include high-technology
companies interested in development of novel materials for photonics and
optoelectronics applications. The development of novel devices for light
control based on suspended semiconductor nanocrystals
and nanostructures can find potential applications not only in fabrication of
TV and computer displays but also in a large variety of products like
low-powered smart windows, skylights, sunroofs and electronic paper. It is also
anticipated that the proposed project will have a major impact on the current
range of methods for preparation of asymmetrically functionalised
nanoparticles. Thus, beneficiaries of the project will include the optoelectronic
industry and high-technology companies concerned with novel optoelectronic
materials, as well as research institutions.
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