Researchers at the National Institute of Standards and Technology (NIST) in the United States have successfully developed a nanoscale coating for solar cells that allows them to absorb up to 20% more sunlight, with this system, they manage to trap sunlight through an optical version of a “whispering gallery”.
This coating paves the way for the development of low cost, high efficiency solar cells with renewable and environmentally friendly materials.
What is behind the coating.
A layer of tiny glass bubbles, the approximate size would be one hundredth of the width of a human hair, when the light reaches the layer, the waves are directed around the bed at the nanoscale, this effect is similar to the sounding shape waves pass through the dome of a dome in a cathedral. In these curved structures, called “ whispering acoustic galleries, ” a person standing near a wall easily hears a faint sound that can come from anywhere on another wall.
In this sense, “whispering galleries” in reference to sunlight began to develop ten years ago, although it is only so far that researchers are beginning to work with them in the field of solar cells.
The team working in this area, made up of Dongheon Ha of NIST and the University of Maryland Nanotechnology Center, found that the light captured by the nanoresonance coating eventually escapes and is absorbed by the solar cell under -jacent made of gallium arsenide.
Coated cells 20% higher energy reception and production.
To measure the effectiveness of the invention they used a laser as a light source to excite the resonators in the coating, which is when the team found that coated solar cells absorbed on average 20% more than solar cells. exposed cells. In the measurement results, the coated cells also produced 20% more energy.
This study is the first to demonstrate the effectiveness of coatings using precision measurements at the nanoscale, according to Ha “Although calculations suggested that the coatings would improve solar cells, we could not prove that this was the case until the necessary nanoscale measurement technologies were developed.”.
Low cost coating.
The team also developed a way to create the coating inexpensively and quickly; In the first test, they pre-coated the semiconductor material with nanoresonance solution in a cuvette, this method is time consuming and covers both sides even though only one side is needed for operation.
To avoid wasting time and material, they decided to use a few drops of resonator solution on one side of the solar cell. A metal rod of string is pulled through the cell, spreading the solution and forming a layer made of resonators.