Flexible, Film-Light Solar Panels Expand Applications on Curved Surfaces

CHINA – A thin, lightweight, paper-like flexible solar cell has just achieved a record efficiency of nearly 27%, opening the door to “sticking” clean energy onto car roofs, backpacks, or virtually any surface.

Traditional solar panels typically use rigid substrates and can usually only be fixedly installed on rooftops or solar farms.

In contrast, flexible perovskite solar cells offer the advantages of being lightweight, thin, and bendable. This characteristic gives the technology the potential to expand into applications that require flexible materials, such as car roofs, wearable devices, backpacks, structures with curved surfaces, or mobile devices.

However, manufacturing high-efficiency flexible cells is far from simple. To fabricate them, scientists must simultaneously deposit two material layers onto a bendable surface: a self-assembled monolayer (SAM) and a perovskite layer.

The problem is that these two layers tend to interact with each other too early, before they can form in the correct positions. As a result, the coating becomes uneven, numerous defects appear, and the cells degrade rapidly when operating in high-temperature, high-humidity environments.

This is precisely the biggest barrier that, despite its full potential, still makes flexible perovskite cells difficult to commercialize.

A research team led by Southeast University and Soochow University in China has found a solution. They added a special type of molecule to the solution used to fabricate the solar cells. This molecule acts as a “mediator,” preventing unwanted interactions between the components of the two layers, thereby helping them form distinct and more stable layers.

The approach, which the research team calls “decoupled co-deposition.”

According to Southeast University, this method enables the SAM layer to bond more effectively with the substrate surface, while the modulating molecule controls the crystal growth of the perovskite. As a result, both material layers are optimized simultaneously, improving film quality and device performance.

Efficiency reaches nearly 27% in small cells

At small scale, the flexible cell achieved an efficiency of 26.86%, meaning that nearly 27 out of every 100 units of incident light were converted into electricity—the highest efficiency ever recorded for this type of cell.

When scaled up, efficiency decreased but remained impressive: the 5×5 cm cell achieved 22.31%, the 10×10 cm cell achieved 20.63%, and the larger 30×30 cm cell achieved 20.15%. According to the research team, these are all records for their respective sizes.

Not only does the cell generate more electricity, it is also more durable. In one test, a 25 cm² flexible cell with an initial efficiency of 22% maintained 92.5% of its efficiency after 1,044 hours of operation at 85°C and 65% relative humidity.

These are harsh conditions, comparable to the hot, dry outdoor environments found in many regions.

The cells also passed rigorous temperature cycling tests and met the international stability standard IEC 63163, which is designed for flexible photovoltaic modules.

According to the research team, meeting this standard lays an important foundation for moving flexible perovskite solar cells from the laboratory to industrial production.

Aiming for the production of solar cells via a continuous printing process

What is noteworthy is not just the efficiency figure. Previously, many records for flexible perovskite solar cells were achieved only on very small laboratory samples, sufficient to document the achievement but difficult to apply in real-world scenarios.

This time, the research team demonstrated that the technology continues to perform well when scaled up into much larger modules. This brings the technology closer to industrial manufacturing: printing solar cells onto rolls of flexible materials, similar to newspaper printing, rather than fabricating individual small panels.

In the coming period, scientists will continue to improve the materials, stack additional cell layers to absorb more light, and refine the continuous production process on flexible rolls.

The ultimate goal is to transform this type of solar cell from a laboratory achievement into a product that can be mass-produced at a reasonable cost.

If successful, flexible solar cells could be manufactured at lower costs, making them suitable for locations that require lightweight, flexible materials and where it is difficult to install traditional rigid solar panels.

Flexible perovskite solar cells, as thin and light as a film, are expanding the range of applications on curved surfaces.

Flexible perovskite solar cells are considered one of the most promising directions in the solar energy industry. Perovskite materials have strong light absorption capabilities, lower production costs than silicon, and can be printed onto flexible substrates. However, stability and lifespan remain significant challenges.

New research from Southeast University and Soochow University does not solve all the problems, but it demonstrates that the barriers related to efficiency and durability are gradually being narrowed.

With efficiencies approaching 27% in small cells and over 20% in large modules, flexible perovskite solar cells are getting closer to the threshold where they can compete with traditional silicon solar cells in certain specialized applications.

If successfully commercialized, this technology could expand the scope of solar energy applications, from car roofs and backpacks to mobile devices and structures with curved or temporary surfaces. This is the vision that many energy companies and investors are awaiting.

The research was published in Science, one of the world’s leading and most prestigious multidisciplinary scientific journals.