Researchers at The Australian National University (ANU) have announced they have achieved a new record efficiency for low-cost semi-transparent perovskite solar cells which they believe moves closer towards lowering the cost of generating solar electricity.
The team led by The Duong from the ANU Research School of Engineering have achieved more than 26% efficiency in converting sunlight into energy, which they researcher said could help make perovskite solar cells a viable alternative to existing silicon cells.
The researchers achieved 26 per cent efficiency by mechanically combining perovskite with silicon solar cells. Silicon solar cell technology is about 90 per cent of the solar market, but scientists around the world are working to find a way to make them more efficient, affordable, stable and reliable.
Figure: ANU - Two full perovskite cells with a perovskite film
The research has been supported by AU$3.6 million in funding from the Australian Renewable Energy Agency.
The research work was part of the "High-efficiency silicon/perovskite solar cells" project led by University of New South Wales with research partners ANU, Monash University, Arizona State University, Suntech R&D Australia Pty Ltd and Trina Solar.
The Duong, a PhD student at The Australian National University, said, "Until now efficiencies of this kind have only been achieved using high cost materials normally used on satellites." The Duong added, "We are now a step closer to a low cost alternative."
Professor Kylie Catchpole from the ANU Research School of Engineering said "The advances in solar technology were good news for consumers, although the perovskite cells were not yet ready for use on rooftops." Kylie added, that "This breakthrough opens the way to increasing the efficiency of silicon solar cells further, and in a cheap way." Kylie concluded by saying, "The key challenge for now is achieving the same stability as we have with silicon solar cells that can be put out on a roof for 20 years using perovskite. Over the next few years we are planning to increase efficiencies to 30 per cent and beyond."
Rubidium Multication Perovskite with Optimized Bandgap for Perovskite-Silicon Tandem with over 26% Efficiency
The Duong | YiLiang Wu | Heping Shen | Jun Peng | Xiao Fu | Daniel Jacobs | Er-Chien Wang | Teng Choon Kho | Kean Chern Fong | Matthew Stocks | Evan Franklin | Andrew Blakers | Ngwe Zin | Keith McIntosh | Wei Li | Yi-Bing Cheng | Thomas P. White | Klaus Weber | Kylie Catchpole
First published: 4 April 2017 | DOI: 10.1002/aenm.201700228
Rubidium (Rb) is explored as an alternative cation to use in a novel multication method with the formamidinium/methylammonium/cesium (Cs) system to obtain 1.73 eV bangap perovskite cells with negligible hysteresis and steady state efficiency as high as 17.4%. The study shows the beneficial effect of Rb in improving the crystallinity and suppressing defect migration in the perovskite material. The light stability of the cells examined under continuous illumination of 12 h is improved upon the addition of Cs and Rb. After several cycles of 12 h light–dark, the cell retains 90% of its initial efficiency. In parallel, sputtered transparent conducting oxide thin films are developed to be used as both rear and front transparent contacts on quartz substrate with less than 5% parasitic absorption of near infrared wavelengths. Using these developments, semi-transparent perovskite cells are fabricated with steady state efficiency of up to 16.0% and excellent average transparency of ≈84% between 720 and 1100 nm. In a tandem configuration using a 23.9% silicon cell, 26.4% efficiency (10.4% from the silicon cell) in a mechanically stacked tandem configuration is demonstrated which is very close to the current record for a single junction silicon cell of 26.6%.