The efficiency of the new perovskite/silicon tandem cell is close to the theoretical upper limit of 35%

Lithium Grid News: For decades, silicon has been the dominant player in the solar cell market, but in recent years it has been gradually buried by 'rising star' perovskites, whose efficiency has risen rapidly from less than 4% in 2009 To 20% earlier this year, it is close to the long-term record of 25% for silicon. But now, engineers have developed a tandem solar cell made of perovskite and silicon with an efficiency of 29.15%, breaking the world record. Not only that, another major feature of this new type of perovskite/silicon tandem battery is that it can maintain stable performance after continuous exposure to air and simulated sunlight for more than 300 hours without encapsulation protection. It is reported that the team used a complex perovskite composition with a 1.68ev band gap and focused on optimizing the substrate interface.

It is understood that compared with a single cell used alone, a solar cell composed of two semiconductors with different band gaps can be used in series to obtain a relatively high efficiency. This is because tandem cells use the solar spectrum more efficiently. In fact, this series design of silicon and perovskite has performed exceptionally as early as five years ago, when its highest efficiency reached 13.7%, two years ago it reached 25.2%, and earlier this year it reached 27.7%. The efficiency of the tandem cell developed by scientists at the Helmholtz Zentrum München in Munich is close to a record 30%, which is not far from the theoretical upper limit of 35%.

Earlier this year, this efficiency record has been certified by the Fraunhofer Institute for Solar Energy Systems and has been included in the NREL chart, which has been since 1976 The progress of solar cell technology has been recorded since the beginning of the year. The research results were also published in the science journal 'Science' recently.

Eike Khnen, the first author of the study and a PhD student in the Albrecht team, said, 'The efficiency of 29.15% is not only a record for this technology, but also at the top of the entire emerging photovoltaic category on the NREL chart. 'For now, the tandem solar cell was tested in a sample of 1 square centimeter, but the researchers said that it should be a relatively simple matter to expand it to a more practical size.