Researchers at MIT created material for absorption of solar radiation
Researchers at Massachusetts Institute of Technology (MIT) created a material that is ideal for absorption of solar radiation..
Researchers at Massachusetts Institute of Technology (MIT) created a material that is ideal for absorption of solar radiation.
The creation of the material was described in a paper published in the journal Advanced Materials in the first week of October 2014. The paper has been co-authored by Jeffrey Chou, a Post-Doc at MIT, Professors Marin Soljacic, Nicholas Fang, Evelyn Wang, and Sang-Gook Kim, and five others.
The material was made by using a formulation that includes a relatively expensive metal ruthenium. The material has a two-dimensional metallic dielectric photonic crystal and is made from a collection of nanocavities.
The material works as part of a solar-thermophotovoltaic (STPV) device wherein the energy of sunlight is first converted to heat, which then causes the material to glow, emitting light that could, in turn, be converted to an electric current.
Process of creating the material
Since, most of the sun’s energy reaches us within a specific band of wavelengths ranging from the ultraviolet through visible light and into the near-infrared. Thus, it’s a very specific window that researchers wanted to absorb in so that they could create a material that would be ideal for converting solar energy to heat.
In order to create the material which can completely absorb the solar radiation and enhance the efficiency of STPV device, the researchers worked on getting just the right spectrum of both absorption and emission.
For this, they worked on an earlier STPV device that took the form of hollow cavities and then they put a dielectric material inside. On this, they found that it had a very good absorption spectrum, just what the researchers wanted.
Key characteristics of the new material
- It can absorb sunlight from a wide range of angles and thus do not need solar tracker which would add greatly to the complexity and expense of a solar power system
- It can withstand extremely high temperatures of 1000 degrees Celsius thus it can take maximum advantage of systems that concentrate sunlight using mirrors
- The material could also be made cheaply at large scales.
- Further the absorption characteristics of material can be controlled with great precision
- The presence of nanocavities ensures that the absorption could be tuned just by changing the size of the nanocavities.
- It is well matched to existing manufacturing technology. This is the first-ever device of this kind that can be fabricated with a method based on current techniques, which means it is able to be manufactured on silicon wafer scales.
This work shows the potential of both photonic engineering and materials science to advance solar energy harvesting