The right measurement and density of quantum dots wanted to realize report effectivity in photo voltaic panels

Quantum dots, man-made nanocrystals that are 100,000 times thinner than a sheet of paper, can be used as light sensitizers that absorb infrared and visible light and transmit it to other molecules.

This could allow new types of solar panels to capture more spectrum of light and generate more electrical power through a process of “light fusion” known as photochemical upconversion.

The researchers from the ARC Center of Excellence in Exciton Science used lead sulfide quantum dots in their example. The algorithm is freely accessible and its results have been published in the journal Nanoscale.

Significantly, existing up-conversion results obtained with test equipment used organic sensitizers that do not work with silicon solar cells – currently the most common type of photovoltaic technology available – because they are unable to absorb much of the infrared portion of the light spectrum.

Using the right size and density of lead sulfide quantum dots as sensitizers would not only lead to efficiency gains, but would also be compatible with almost all existing and planned solar cell technologies.

These results show that quantum dot size is not as simple as larger, which means better.

Using a basic theory, a larger quantum dot appears to be able to capture more colors of sunlight or more light of a given wavelength and help create a device with greater efficiency.

However, the researchers considered several practical limitations on quantum dot size.

Most importantly, the near-infrared portion of sunlight on the surface of the earth has a complicated structure that is influenced by water in the atmosphere and the heat of the sun.

This means that the color of the quantum dot must be adjusted to match the peaks of sunlight, for example when a musical instrument is tuned to a certain pitch.

According to the corresponding author Dr. Laszlo Frazer’s work shows that a complete picture of the conditions that affect solar cell performance, from the star in the center of our solar system to nanoscale particles, is necessary to achieve maximum efficiency.

“This whole thing requires an understanding of the sun, the atmosphere, the solar cell and the quantum dot,” he said.

While the projected efficiency gains shown by these results remain modest, the potential benefits are considerable as they can be used in nearly all solar devices, including those made from silicon.

The next step for researchers is to design and manufacture emitters that will most effectively transfer energy from the optimized quantum dot sensitizers.

“This work says a lot about the detection of light,” said Laszlo.

“The republication urgently needs to be improved. Multidisciplinary contributions are definitely required here. “

Monash University writer Benedicta Sherrie said, “More work needs to be done to build and test prototype solar cells with these sensitizers (and hopefully the appropriate emitters).

“I hope that ultimately this research will allow society to rely more on photovoltaic solar energy, which is not only efficient but also affordable.”

Publication referred to in the article:

Benedicta Sherrie, Alison M. Funston and Laszlo Frazer. Optimal quantum dot size for photovoltaics with fusion. Nanoscale, 2020; DOI: 10.1039 / D0NR07061K

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