The future is bright for solar

From water heating to lighting systems and transportation, the growing number of applications are fuelling the growth of this market.

According to information released by SolarPower Europe in a market outlook report on solar power from 2023-2027, in 2022 the world installed 239GW of new solar - 45% more than the year previously, and solar remained a cheaper source of power than fossil fuels and nuclear. Challenges that need to be addressed to facilitate further growth of the market include limited grid capacity and a lack of storage in national electricity systems

Copper Indium Gallium Selenide (CIGS) solar cells are a popular form of thin-film solar technology, boasting cost-efficiency, a high power output and low environmental footprint. The cell is made up of thin layers, each of which serve their own purpose. The design allows for high absorption and durability, with a lightweight and flexible design which can be shaped to fit into residential and commercial buildings to provide solar power.

News from the Uppsala University showed a new world record for electrical energy generation made from CIGS solar cells; 23.64% efficiency. The results were published in the journal Nature Energy and verified by measurement institution Fraunhofer ISE. “Our study demonstrates that CIGS thin-film technology is a competitive alternative as a stand-alone solar cell. The technology also has properties that can function in other contexts, such as the bottom cell of a tandem solar cell,” said Marika Edoff, Professor of Solar Cell Technology at Uppsala University, who was responsible for the study.

The achievement obtained by Uppsala University not only reflected a growing market of solar energy as solar power accounted for 6% of electricity worldwide in 2022 according to the International Energy Agency, but aims to make solar cells more efficient with reduced production costs. The challenge is to use a material that can absorb enough sunlight without wasting this energy and converting it accordingly.

The measurement to verify the world record appeared as important as the study itself, as existing measurement methods seek to understand a correlation between efficiency and solar cell structure. Different measurement methods include nano-XRF, which characterises the solar cell material; transmission electronic microscopy (TEM) which studies the cross sections of  the cell; and photoluminescence, which measures how the solar cell takes care of electrons internally.

“The measurements that we have made ourselves for this solar cell and other solar cells produced recently are within the margin of error for the independent measurement. That measurement will also be used for an internal calibration of our own measurement methods,” explained Edoff.

“The fact that we now hold the world record means a lot for both Uppsala University and First Solar European Technology Center. For the CIGS technology, which is known for high reliability, a world record also means that it may offer a viable alternative for new applications in e.g. tandem solar cells. This is important for our research colleagues around the world. We hope that the analyses of the material and electric properties will provide a basis for further improvements in performance,” concluded Edoff.