The new generation solar, developed by TalTech, cells contribute to the green revolution

December 01, 2020

The European Union is determined to undertake a major reform known as the European Green Deal with an aim of making Europe the first climate neutral continent in 2050. The biggest changes will take place in the energy production sector, which stands on the brink of a complete transition to renewable energy sources, including solar energy. To boost the power output of solar cells to a terawatt-scale, technologies that leave a smaller ecological footprint, are more efficient and offer a wider range of applications need to be developed alongside with the first-generation silicon-based solar cells currently dominating in the solar cell market.

TalTech's photovoltaic materials and optoelectronic materials physics research groups published an article in the journal Solar Energy titled "The effect of S/Se ratio on the properties of Cu2CdGe(SxSe1?x)4 microcrystalline powders for photovoltaic applications", which focused on the development of the new generation monograin layer solar cells.

One of the authors of the article, Head of the TalTech Laboratory of Photovoltaic Materials, Senior Researcher Marit Kauk-Kuusik says, "Unlike the widespread silicon-based solar panels, the next-generation solar cells are made of very thin layers of material. To build such solar cells, semiconductors with very good light-absorbing properties must be used. As is known, light absorption in silicon is rather poor, thus requiring relatively thick absorber layers, which make solar cells heavy and rigid. Our research focused on the analysis of the potential applications of the Cu2CdGe(SxSe1?x)4 semiconductor in the production of solar energy. In this study, we focused on the effect of sulfur/selenium (S/Se) ratio on the optoelectronic properties of the absorber material in order to maximise the spectral sensitivity range."

Solar cell works on the principle of photovoltaic effect, i.e. energy can be produced directly by light. A solar cell absorber should be able to absorb light as efficiently as possible, in particular to harness the full spectrum of wavelengths in solar radiation. In addition, the absorption coefficient of the absorber material must be as high as possible, which means that already a very thin layer of the absorber should absorb all the incident light. This in turn means that less material is required to produce an absorber than in case of a lower absorption coefficient. Therefore, while absorbers made of silicon, which is a material with a low absorption coefficient, are 150-200 μm thick, the layers of modern absorber materials based on monograin powders can be 5-10 times thinner (i.e. 10-30 μm thick). It also automatically reduces the weight of the solar cell.

Lower weight of solar sells also means a decrease in material consumption, which is of course not of minor importance in our current era of increase in environmental awareness and green revolution. "It is important to consistently search new alternatives to the existing silicon-based solar cells used for decades," Marit Kauk-Kuusik says. The trend is towards environmental friendliness and overall sustainability. In addition to reduced material consumption and weight, the new solutions are also much more innovative. The keywords are still high-performance, lightness, flexibility and durability.

While conventionally costly vacuum evaporation or sputtering technologies have been widely used to produce solar cells, the unique monograin powder technology applied by TalTech material researchers does not require any high vacuum equipment. Microcrystalline powder is synthesized by molten salt method in quartz ampoules in a special chamber furnace. The mass obtained is washed and sieved into narrow size fractions by a special sieving system and the synthesized high-quality microcrystalline powder, monograin powder, is used for the production of solar cells.

Marit Kauk-Kuusik says, "The monograin powder produced by our powder technology consists of microcrystals that form miniature solar cells in a large module. This provides major advantages over silicon-based solar panels: the material is lightweight, flexible, can be semi-transparent, while being environmentally friendly and significantly less expensive."

Environmentally friendly energy production has become vital in the light of the green revolution and sustainable consumption. Renewable energy, where solar energy plays an increasingly significant role, is an important keyword here.

"The power conversion efficiency of the solar cell developed as a result of our research is 6.4%, which is world highest published performance for Cu2CdGe(SxSe1?x)4 based solar cells and slightly higher than that of the world's first, silicon-based cell developed decades ago. Thus, it is a promising result," Kauk-Kuusik says. She is also convinced that, unlike with this invention, it will no longer take 30 to 40 years to achieve higher power conversion efficiency, as was the case with the silicon, but results in science will be achieved in a much shorter period of time.
-end-
Source: Solar Energy "The effect of S/Se ratio on the properties of Cu2CdGe(SxSe1?x)4 microcrystalline powders for photovoltaic applications", 10.2020 https://www.sciencedirect.com/science/article/pii/S0038092X2030997X

Additional information: Researcher at TalTech Laboratory of Photovoltaic Materials Marit Kauk-Kuusik, marit.kauk-kuusik@taltech.ee

Kersti Vähi, TalTech Research Administration Office

Estonian Research Council

Related Solar Cells Articles from Brightsurf:

Solar cells of the future
Organic solar cells are cheaper to produce and more flexible than their counterparts made of crystalline silicon, but do not offer the same level of efficiency or stability.

A blast of gas for better solar cells
Treating silicon with carbon dioxide gas in plasma processing brings simplicity and control to a key step for making solar cells.

Record efficiency for printed solar cells
A new study reports the highest efficiency ever recorded for full roll-to-roll printed perovskite solar cells.

Next gen solar cells perform better when there's a camera around
A literal ''trick of the light'' can detect imperfections in next-gen solar cells, boosting their efficiency to match that of existing silicon-based versions, researchers have found.

On the trail of organic solar cells' efficiency
Scientists at TU Dresden and Hasselt University in Belgium investigated the physical causes that limit the efficiency of novel solar cells based on organic molecular materials.

Exciting tweaks for organic solar cells
A molecular tweak has improved organic solar cell performance, bringing us closer to cheaper, efficient, and more easily manufactured photovoltaics.

For cheaper solar cells, thinner really is better
Researchers at MIT and at the National Renewable Energy Laboratory (NREL) have outlined a pathway to slashing costs further, this time by slimming down the silicon cells themselves.

Flexible thinking on silicon solar cells
Combining silicon with a highly elastic polymer backing produces solar cells that have record-breaking stretchability and high efficiency.

Perovskite solar cells get an upgrade
Rice University materials scientists find inorganic compounds quench defects in perovskite-based solar cells and expand their tolerance of light, humidity and heat.

Can solar technology kill cancer cells?
Michigan State University scientists have revealed a new way to detect and attack cancer cells using technology traditionally reserved for solar power.

Read More: Solar Cells News and Solar Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.