Researchers at the University of Surrey have made significant advancements in solar technology by exploring the use of carbon nanotubes to replace indium tin oxide (ITO) in perovskite solar cells. This innovative approach promises to enhance the efficiency, durability, and cost-effectiveness of flexible solar panels, potentially revolutionizing the solar energy industry.

Perovskite solar cells have gained attention for their remarkable efficiency and low production costs, but they have been hindered by the fragility and expense of ITO, a common transparent conductive material. The research team, led by Professor Wei Zhang from the Advanced Technology Institute, found that single-walled carbon nanotubes (SWCNTs) could serve as a more robust alternative. Their study indicates that a sulfuric acid treatment applied to the carbon nanotube films significantly improves their electrical conductivity while allowing sufficient light to penetrate to the solar layer beneath.

The newly developed solar cells, which do not rely on ITO, achieved over 20% power conversion efficiency across large areas, with small-scale devices reaching a record efficiency of 24.5%. This performance is particularly noteworthy given the challenges associated with scaling up solar technology for commercial applications.

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One of the standout features of this research is the durability of the SWCNT-based solar cells. The team conducted tests that revealed these new devices maintained over 95% of their original performance after a month of exposure to heat, humidity, and sunlight—significantly outperforming traditional ITO-based designs. Additionally, while conventional ITO devices suffered a nearly 75% efficiency loss after 1,000 bends, the carbon nanotube versions only lost about 5%, demonstrating superior mechanical strength and flexibility.

The manufacturing process for these carbon nanotube films utilizes roll-to-roll chemical vapor deposition, a technique already established in large-scale electronics production. This method not only enhances the scalability of production but also reduces costs significantly. The researchers estimate that producing SWCNT films is approximately six times cheaper than ITO sputtering, potentially lowering manufacturing costs by around $200 per square meter. Given the scarcity and energy-intensive extraction process of indium, this shift to carbon-based materials could also lead to a more environmentally friendly solar manufacturing process.

Perovskites, often referred to as a “miracle material” in solar research, are made from low-cost ingredients and can be processed at lower temperatures compared to traditional silicon. Their flexible nature allows for innovative applications, including solar panels that can be integrated into various surfaces and structures.

Professor Zhang emphasized that their findings address significant barriers to the commercialization of flexible solar technology, suggesting that these advancements could lead to lightweight solar modules suitable for powering portable electronics and next-generation building materials. As the solar industry continues to seek solutions for efficiency and sustainability, the integration of carbon nanotubes into perovskite solar cells represents a promising direction for future developments in renewable energy.