Perovskite solar cells designed by a team of scientists from the National University of Singapore (NUS) have attained a world record efficiency of 24.35 per cent with an active area of one square centimetre, an achievement that paves the way for cheaper and more efficient and durable solar cells.
To facilitate consistent comparisons and benchmarking of different solar cell technologies, the photovoltaic community uses a standard size of at least one square centimetre to report the efficiency of one-sun solar cells in the so-called Solar Cell Efficiency Tables. Prior to the record-breaking feat by the NUS team, the best one-square-centimetre perovskite solar cell recorded a power conversion efficiency of 23.7 per cent.
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Perovskites are a class of materials that exhibit high light-absorption efficiency and ease of fabrication, making them promising for solar cell applications. In the past decade, perovskite solar cell technology has achieved several breakthroughs and the technology continues to evolve.
‘To address this challenge, we undertook a dedicated effort to develop innovative and scalable technologies aimed at improving the efficiency of one-square-centimetre perovskite solar cells. Our objective was to bridge the efficiency gap and unlock the full potential of larger-sized devices,’ said assistant professor Hou Yi, leader of the NUS research team.
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‘Building on more than 14 years of perovskite solar cell development, this work represents the first instance of an inverted-structure perovskite solar cell exceeding the normal structured perovskite solar cells with an active area of one square centimetre, and this is mainly attributed to the innovative charge-transporting material incorporated in our perovskite solar cells,’ Hou added. ‘Since inverted-structure perovskite solar cells always offer excellent stability and scalability, achieving a higher efficiency than for normal-structured perovskite cells represents a significant milestone in commercialising this cutting-edge technology.’
The record-breaking accomplishment was made by successfully incorporating a novel interface material into perovskite solar cells. ‘The introduction of this novel interface material brings forth a range of advantageous attributes, including excellent optical, electrical and chemical properties. These properties work synergistically to enhance both the efficiency and longevity of perovskite solar cells, paving the way for significant improvements in their performance and durability,’ explained Li Jia, a postdoctoral researcher at the Solar Energy Research Institute of Singapore.
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The promising results reported by the NUS team mark a pivotal milestone in advancing the commercialisation of a low-cost, efficient, stable perovskite solar cell technology. ‘Our findings set the stage for the accelerated commercialisation and integration of solar cells into various energy systems. We are excited by the prospects of our invention, which represents a major contribution to a sustainable and renewable-energy future,’ said Wang Xi, an NUS doctoral student.
Building upon this exciting development, Hou and his team aim to push the boundaries of perovskite solar cell technology even further. A key area of focus is to improve the stability of perovskite solar cells, as perovskite materials are sensitive to moisture and can degrade over time. ‘We are developing a customised accelerated-aging methodology to bring this technology from the lab to the fab,’ said Hou. ‘One of our next goals is to deliver perovskite solar cells with 25 years of operational stability.’
The team is also working to scale up the solar cells to modules by expanding the dimensions of the perovskite solar cells and demonstrating their viability and effectiveness on a larger scale. ‘The insights gained from our current study will serve as a roadmap for developing stable, and eventually, commercially viable perovskite solar cell products that can serve as sustainable-energy solutions to help reduce our reliance on fossil fuels,’ Hou concluded.