Tandem Cells Without Interlayer

A team of engineers from the Australian National University (ANU) and researchers from the California Institute of Technology have developed a way to create a tandem cell without the need to have an interlayer, which they claim simplifies the structure and makes it cheaper and easier to produce.

Using the analogy of a club sandwich, the team said in their process, they don’t need to put an extra layer of bread or interlayer between 2 tandem cells. They combined silicon with perovskite to more efficiently convert sunlight into electricity.

The current power conversion lab efficiency record for single-junction Si solar cells is 26.6%, closely approaching the theoretical limit of 29.4. “In order to continue the transition to a renewable energy based economy, we need to keep reducing the cost of solar energy, and the best way to do that is to increase the efficiency of solar cells,” said study co-author Dr Helping Shen.

When done right, the tandem boosts efficiency of the cell, well beyond what is possible with silicon by itself. “We’ve already reached 24% improvement in efficiency with this new structure, and there’s plenty of room left to grow that figure,” said co-author of the study Dr. Daniel Jacobs.

The study was published in the journal Science Advances and funded by a grant from the Australian Renewable Energy Agency (ARENA), as part of a project in collaboration with the University of New South Wales and Monash University.

In July 2018, Belgian research institute Imec achieved 27.1% efficiency for a 4-terminal perovskite/silicon tandem PV cell, and claimed it can go beyond 30% with further research (see 27.1% Perovskite/Si Tandem Cell From IMEC).