The Indian Institute of Technology (IIT) Guwahati, India, and Imperial College London, United Kingdom, have developed nanoparticles called the ‘meta-grid’ or ‘metamaterial grid’ that makes the light-emitting diodes (LED) brighter, energy-efficient and durable.
It was jointly developed by Dr. Debabrata Sikdar, assistant professor at IIT Guwahati along with Prof. Sir John B. Pendry and Prof. Alexei A. Kornyshev from Imperial College London.
NOTE: The findings have been recently published in Light: Science and Application journal of the Nature Publishing Group. The theoretical models, developed by Dr. Sikdar, find out the optimal conditions for the design of the nanoparticle ‘meta-grid’ layer.
What is Meta – grid?
Meta-grid is a specifically patterned array of nanoparticles acting as metamaterials and it is capable of exhibiting extraordinary optical properties.
Features of the Meta grid:
- The nanoparticle ‘meta-grid’ enhances the light extraction and provides a wider range of optical gadgets.
- The ‘meta-grid’ can be used as drying-mediated self-assembly of nanoparticles made of silver or alternative less-lossy plasmonic materials capped with appropriate ligands, to form free-standing the Sikdar–Premaratne–Cheng ‘plasmene’ sheets.
- These monolayer sheets can be stretched for precise tuning of the plasmene’s substrate.
i.LEDs are deployed in traffic lights to backlighting for electronic displays, smartphones, large billboards, decorative lightings, water purification, and decontamination of infected surfaces.
ii.An increase in LED light output would reduce energy needs on a large scale, this might help us to put up with the increasing global warming and climate change.
Components LED-chip encapsulation
- The LED-chip encapsulation may include: higher refractive index glasses or epoxy materials incorporated with filler powders or nanoparticle-loaded-epoxy or engineered epoxy resins.
- These materials make LED chips bulkier or their fabrication becomes more challenging and less economically viable for mass production.
- Material and composition of nanoparticles and parameters are: sizes, average interparticle spacing, distance from the surface of the LED chip
- These are optimised to achieve the maximum enhancement in light extraction from the LED chip into its encapsulating casing, over any emission spectral range of a typical LED.
i.The boosting transmission of light generated inside an LED chip or the encapsulate interface has been recently achieved.
ii.This is achieved by reducing the Fresnel reflection loss at the chip or the interface, within a fixed photon escape cone, based on tuning the destructive interference phenomena with help of the ‘meta-grid’.
iii.The technique has revealed optimal design parameters for meta-grids to produce greater light output over any narrow or broadband emission spectrum.
Prototype of the embedded meta-grid LED:
i.The prototype device can be modeled within one year which can corroborate theoretical predictions with experiments.
ii.The metallic nanoparticles can be fabricated which are mostly monodisperse and have narrow spread.
iii.The prototype may vary in size, position, flatness of grid, and variation in refractive index due to fabrication error or material defects and these cannot be avoided.
iv.The effects of the ‘meta-grid’ on the standard commercial LEDs, based on group III–V materials are demonstrated in the developed prototype.
Recent Related News:
i.On June 07,2020, A team of Scientists from the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous R&D Centre of Department of Science and Technology (DST) has developed a magnetocaloric material (a rare-earth-based material that can be heated or cooled by applying or removing a magnetic field) that can be used in the treatment of cancer.
About Indian Institute of Technology (IIT) Guwahati
Headquarters – Guwahati, Assam, India
Director – T.G Sitharam
About Imperial College London
President – Alice P. Gast
Headquarters – London, United Kingdom