The newly developed tandem solar cells have surpassed the threshold of 30% energy efficiency, marking a significant step towards further reducing the cost of solar energy and accelerating green energy conversion.
According to scientists, this development heralds a new era in solar energy. Details of pioneering studies that have pushed the efficiency of tandem (multi-junction) solar cells beyond 30% were published in two articles last week in the journal Science, by Chin et al. and Mariotti et al.
Currently, the widely used silicon solar cells have a practical upper limit of approximately 27% efficiency, which we are approaching within a few years. In order to maximize the benefits of solar panels in global green energy conversion and accelerate this transition process, it is necessary to develop new and more efficient technologies. Tandem solar cells can provide significant opportunities in this regard.
Tandem solar cells enable the highest level of utilization of solar radiation. By combining silicon solar cells that absorb red light more efficiently with perovskite-based solar cells that absorb blue light more effectively, a greater amount of energy can be generated. This approach aims to further reduce the cost of solar energy and accelerate green energy conversion.
Despite the global installed capacity of solar energy reaching 1.2 TW in 2022, it still accounts for only about 5% of global electricity generation. According to the International Energy Agency, in order to limit the impacts of global warming, the installed capacity needs to increase by 25% annually until 2030. Technological advancements such as tandem solar cells play a crucial role in accelerating this transformation.
Dr. Erkan Aydın, who is part of a team conducting research on tandem solar cells at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, shared the following information regarding their development of photovoltaic devices that have achieved a record efficiency of 33.7%.
Tandem solar cells have the potential to create a revolution.
Research on combining perovskite materials with silicon solar cells to create tandem structures began in 2013. Since then, numerous research groups have been conducting studies in this field. The development of record-efficient certified cells, as summarized in a graph prepared by the National Renewable Energy Laboratory (NREL) in the United States, has shown a remarkable acceleration in recent years.
The first cells to exceed 30% efficiency were published in July 2022 by the research team at EPFL-CSEM (École polytechnique fédérale de Lausanne – Swiss Centre for Electronics and Microtechnology) in Switzerland. In December of the same year, the research team at HZB (Helmholtz Zentrum Berlin) in Germany announced a significantly high efficiency value of 32.5%. This year, my team at KAUST (King Abdullah University of Science and Technology), where I am one of the lead researchers, published record efficiency values of 33.2% in April and 33.7% in May. These are currently the highest reported values. We anticipate that this efficiency value can be increased up to approximately 37% in laboratory-scale experiments in the coming years.
In addition to these achievements, we are aware that global photovoltaic companies are also actively conducting research in this field. For example, Longi, a China-based company, announced last month at the Intersolar Europe exhibition in Germany that they have achieved an efficiency value of 33.5%.
To achieve commercialization, scalability and operational lifespan challenges must also be overcome.
During this process, perovskite-silicon tandem solar cells have proven themselves to be highly efficient photovoltaic technology without any doubt. However, the reported devices are still at the laboratory scale. The key challenges that need to be overcome for commercialization include scaling up the production methods of this technology to commercial levels and achieving stability that meets today’s market standards. While scalability can be considered as a challenge that can be technically overcome with technological advancements, stability, or operational lifespan, requires intensive research.
Today, companies can provide performance guarantees for photovoltaic modules for up to 25 years. This can also be considered as a target for perovskite-silicon tandem solar cells. Since we cannot wait for such a long period to understand their stability, accelerated aging tests and their compatibility with outdoor exposure tests need to be considered together to evaluate their stability.
Commercial products could enter the market within 5 years.
The success of this technology commercially relies not only on efficiency but even a modest increase of 1% to 3% over current silicon photovoltaic modules could be sufficient. Other crucial factors include the cost increase associated with perovskite cell production and the longevity of these modules in terms of maintaining performance and energy generation. These aspects are still being researched.
The success of perovskite-silicon tandem solar cells will depend on the performance of the final product and the dynamics of the photovoltaic market. Based on the progress in the field, my estimation is that within five years, the first large-scale commercial products will be available in the market.
Source iklim masasi