27 Sep 2018
CIGS or silicon solar cells are integrated with perovskite to use different parts of spectrum boosting overall output.imec, based in Leuven, Belgium, has presented its newly-developed tandem solar cell technologies, which it says “pave the way to higher cell efficiencies of PV panels on roofs, vehicles in solar cells in windows or building façades.
Tandem cells combine two types of solar cells applied on top of each other. Because each cell uses a different part of the sunlight spectrum, very high optical-elctrical efficiencies above 30% can be achieved.
In its tandem cells, imec combines copper indium gallium selenide (“CIGS”) or silicon solar cells with perovskite. As perovskite solar cells utilize the visible part of the light spectrum, they are ideally suited to combine with CIGS or Si solar cells, which utilize more the near-IR light portion of the spectrum.
The two formulations
The perovskite-silicon cell combines imec’s 0.13cm2 perovskite cell, developed within the Solliance collaboration, with a 4.0cm2 silicon solar cell. The tandem cell achieves a conversion efficiency of 27.1 percent, which is higher than today’s best silicon solar cell (26.6 percent).
The perovskite/CIGS cell combines the 0.13 cm2 perovskite cell with a 3.8 cm2 CIGS module developed by Zentrum für Solare Energiewirtschaft (ZSW), in Stuttgart, Germany. This second tandem cell achieves 24.6 percent efficiency, which is also higher than the current leading CIGS solar cells in the industry (22.9 percent).
“According to the International Technology Roadmap for PV (ITRPV), tandem solar cells are expected to appear in the market in 2021,” commented Tom Aernouts, group leader thin-film PV at imec/Energyville.
“At imec, we work on perovskite/silicon as well as on perovskite/CIGS tandems because each technology is directed towards different applications. For instance, silicon solar cells are especially suited for roofs and in solar cell parks, while CIGS thin-film solar cells can be produced on foils that could, in the future, be applied for building-integrated PV, turning facades and windows into electricity producers.”
"We are pleased that our new perovskite-based tandem cell technologies will further enhance the capabilities of these solar cells towards 30 percent.”