Perovskite Tandem Cell 29.15% Efficiency Record 

• HZB team of researchers claim to have reached the efficiency level of 29.15% for tandem solar cells
• Comprising perovskite and silicon, the tandem solar cells till now had the highest efficiency of 28%, reported by Oxford PV in December 2018
• HZB now is aiming to exceed 30% mark but sees the potential to go up to around 35% in the future

German researchers reported a record efficiency level of 29.15% for a perovskite and silicon tandem solar cell. CalLab of the Fraunhofer Institute for Solar Energy Systems (ISE) has certified the value achieved by a Helmholtz Zentrum Berlin (HZB) team. 

With this, HZB has broken its own previous highest value of 25.5% for this configuration reported in November 2018. At the same time, the team has exceeded the 28% power conversion efficiency reported by British company Oxford PV in December 2018.

The team argues that the practical, realistic limit for the efficiency of perovskite and silicon tandem cells is around 35% and that it will be targeting to overcome the 30% efficiency barrier.

The HZB team led by Steve Albrecht and Bernd Stannowski, reworked several layers that make up this tandem cell by developing a special new contact layer and optimizing another intermediate later for the record cell to realize the 29.15% level that was reported using a typical laboratory scale of 1 cm2

"In principle, all processes used to implement this square centimeter cell are also suitable for large areas. Initial attempts using vacuum processes have already been very successful," said the team.