Feature
Thin. Light. Flexible. The Amazing Future of Solar Power: Perovskite!
Index
What Are Perovskite Solar Cells, the Solar Panels of the Future?
A 1mm Film Shaping the Future of Energy
Locally Sourced Materials, Japanese Innovation: "Local Production for Local Consumption" Energy
Pioneering World-First Technology to Achieve GX
The solar panels you often see on the roofs of homes and apartment buildings are a familiar sight. In fact, when measured by land area, Japan ranks as the leading country among major nations in terms of solar panel installations.
However, to achieve GX (Green Transformation) — the shift from a fossil fuel-dependent society to one centered on clean energy — further innovation in solar power technology is essential.
Enter the perovskite solar cell — a revolutionary advancement that promises to be lighter, thinner, and more adaptable to various surfaces while also reducing environmental impact.
This remarkable technology has the potential to overcome multiple challenges, paving the way for a brighter future in solar power. In this article, we’ll delve into the potential of perovskite solar cells and the fascinating story behind their development.
What Are Perovskite Solar Cells, the Solar Panels of the Future?
As the global push for renewable energy gains momentum, Japan’s Ministry of Economy, Trade and Industry (METI) has set a target for renewables to account for 40–50% of the country’s energy mix by 2040. Among these renewable sources, solar power is expected to play a major role.
Japan is already a leader in solar power adoption among developed nations. Despite its relatively limited land area, proactive policies have successfully promoted the widespread installation of solar panels. As a result, Japan boasts the highest solar panel capacity per unit of flat land area among major countries — more than double that of Germany, a country renowned for its commitment to renewable energy.
In Japan, where about 70% of the land is mountainous, the installation of traditional solar panels faces several challenges. The most significant issue is site limitations. Traditional panels are heavy — weighing around 15 to 20 kg per panel for residential use — and require flat surfaces for installation, making it difficult to secure suitable locations.
Additionally, the growing frequency of natural disasters poses another concern. Traditional panels are vulnerable to damage from typhoons and earthquakes, and installations on steep slopes risk being destroyed by landslides. Environmental concerns also come into play. Traditional panels require a significant amount of energy during manufacturing and generate considerable CO₂ emissions when disposed of.
A promising solution to these challenges lies in the film-type perovskite solar cell (hereafter referred to as perovskite) — a revolutionary technology that is just 1mm thin, lightweight, and flexible. This flexibility allows perovskite cells to be installed in locations previously considered unsuitable for solar panels. Additionally, while traditional silicon-based panels require temperatures exceeding 1000°C during manufacturing, perovskite cells can be produced at temperatures below 150°C, significantly reducing energy consumption during production.
A 250m-long perovskite solar power system will be installed at the bus terminal, the gateway to the Osaka-Kansai Expo. This will be the world's largest perovskite installation as of 2025, offering visitors a firsthand look at the future of solar power.
A 1mm Film Shaping the Future of Energy
What makes the perovskite solar cells installed at the gateway to the Osaka-Kansai Expo so remarkable? To explore the background and groundbreaking innovation behind this technology, we spoke with Mr. Futoshi Kamiwaki, President of Sekisui Solar Film Co., Ltd., the company responsible for its development.
At the Osaka-Kansai Expo, the perovskite solar cells developed by your company will be installed on the roof of the bus terminal. I understand this will be the world's largest installation of its kind, correct?
Kamiwaki
The Osaka-Kansai Expo presents a crucial opportunity to showcase Japan's innovative future technologies to the world. At the same time, it serves as a platform to demonstrate how perovskite solar cells can contribute to climate change mitigation and CO₂ reduction, while also highlighting their unique potential for installation on curved surfaces and other challenging locations.
Japan's technology is currently leading the world in perovskite solar cell development. To showcase the achievements of this ongoing innovation, our company has dedicated significant effort to the installation at the Osaka-Kansai Expo.
What are the key features of the perovskite solar cells developed by your company?
Kamiwaki
The Osaka-Kansai Expo presents a crucial opportunity to showcase Japan's innovative future technologies to the world. At the same time, it serves as a platform to demonstrate how perovskite solar cells can contribute to climate change mitigation and CO₂ reduction, while also highlighting their unique potential for installation on curved surfaces and other challenging locations.
Japan's technology is currently leading the world in perovskite solar cell development. To showcase the achievements of this ongoing innovation, our company has dedicated significant effort to the installation at the Osaka-Kansai Expo.
What are the key features of the perovskite solar cells developed by your company?
Kamiwaki
Our perovskite solar cells have three key features that set them apart from traditional solar panels:
1. Lightweight Design:
Our perovskite cells are approximately one-tenth the weight of conventional solar panels. This significant reduction in weight allows installation in locations that were previously unsuitable due to load restrictions, such as gymnasium roofs or older buildings.
2. Flexibility:
Unlike rigid traditional panels, our perovskite cells are flexible, enabling installation on curved surfaces. For instance, at the Osaka-Kansai Expo, the perovskite system is designed to follow the curved roof of the bus terminal. We are also conducting demonstration tests in various locations, including soundproof walls along Shinkansen tracks.
3. Thin Profile:
Our perovskite cells are just 1mm thick. This slim profile allows seamless integration into walls and building materials without compromising aesthetics, making solar power adoption possible without disrupting design.
While traditional solar panels achieve an energy conversion efficiency of around 20%, our perovskite cells currently achieve about 15%. However, we expect to reach comparable efficiency levels in the near future.
Features of Perovskite Solar Cells
Weight: Approximately one-tenth of traditional panels
Installation Flexibility: High (suitable for curved surfaces)
CO₂ Emissions During Production: Significantly lower than traditional panels
Locally Sourced Materials, Japanese Innovation: "Local Production for Local Consumption" Energy
What enabled your company to successfully develop perovskite solar cells?
Kamiwaki
We began development about 12 years ago. Even back then, perovskite was gaining attention as a promising next-generation solar cell technology, but no company had yet achieved mass production. Recognizing that our company's technical strengths could play a key role, we decided to take on the challenge of development.
What kind of technology is used in the development of perovskite solar cells?
Kamiwaki
We utilized technologies developed through our experience with liquid crystal displays, such as film encapsulation (a technique that seals and protects semiconductors without gaps), precise coating on thin films, and plastic molding techniques. By combining these technologies, we believed we could make perovskite solar cells practical for real-world use.
The result is a 1mm-thick film-type solar cell composed of multiple layers — a product that embodies the expertise and innovations we have cultivated over the years.
What materials are used to create perovskite solar cells?
Kamiwaki
One of the main raw materials used is iodine, which can be sourced domestically in Japan. This iodine is extracted from brine pumped from underground. Most of Japan's iodine is collected in Chiba Prefecture, ensuring a stable and reliable domestic supply — a significant advantage in production.
So, the main raw material can be sourced domestically?
Kamiwaki
In fact, Japan accounts for approximately 30% of the world's iodine production, making it the second-largest producer globally. Sourcing raw materials domestically is extremely important from the perspective of energy security and economic security. This is not just about material procurement — it also contributes to building a stable production system that leverages Japan's technological expertise.
On the other hand, the primary raw material for traditional solar cells, silicon, is almost entirely dependent on imports from China. As a result, China has gained a competitive edge in the global market through large-scale production supported by low-cost materials, leaving Japan struggling to compete. In contrast, perovskite solar cells offer a competitive advantage as their raw materials can be sourced domestically. Additionally, the manufacturing process for perovskite does not require the high-temperature treatments typical of silicon solar cell production, significantly reducing energy consumption and CO₂ emissions.
Pioneering World-First Technology to Achieve GX
What was the most challenging aspect of the development process?
Kamiwaki
The biggest challenge was improving durability. Perovskite is prone to degradation from moisture and light, so we focused heavily on developing film encapsulation technology. This allowed us to create a system that effectively blocks moisture and prevents light-induced deterioration. Currently, our perovskite cells have achieved a durability of approximately 10 years after installation. However, this is still a work in progress. We are continuing our efforts to extend the lifespan to 20 years, comparable to traditional solar panels.
We are also focusing on expanding the film width used in production from the current 30 cm to 1 meter. If achieved, this will mark a world-first technological breakthrough.
Are there specific technical challenges involved in increasing the film size?
Kamiwaki
The challenge isn’t simply about increasing the size itself — the real difficulty lies in maintaining quality as the film size grows.
During the manufacturing process, the raw materials must be applied to the film in a uniform layer. Any inconsistencies or unevenness can significantly reduce the power generation efficiency. As the film size increases, achieving this level of precision and consistency becomes much more difficult.
I had imagined layering panel-like materials, but it sounds like the materials are actually applied in a coating process?
Kamiwaki
It’s a unique and highly complex technology, but if successful, it is expected to significantly reduce both manufacturing and installation costs. Achieving this would be a major step forward in promoting the widespread adoption of perovskite solar cells, and we are committed to making it happen.
When can we expect to see perovskite solar cells integrated into our daily lives as mass production advances?
Kamiwaki
We are currently conducting demonstration tests in various environments, such as sewage treatment plant covers, cruise terminal pillars, and Shinkansen soundproof walls. Through these tests, we’ve learned that to fully utilize the benefits of perovskite’s lightweight and thin design, minimizing installation effort is crucial. Ensuring ease of installation will be a key factor in promoting its widespread adoption.
Looking ahead, we plan to begin shipping in fiscal year 2025 and commence full-scale mass production at our Sakai plant in 2027. The plant will initially produce at a 100-megawatt scale, with plans to expand to 1 gigawatt by 2030.
As for implementation, we aim to start with public facilities such as gymnasiums in elementary and junior high schools and disaster prevention facilities. Gymnasiums, in particular, have traditionally faced challenges with solar panel installation due to weight limitations. However, since these spaces often serve as evacuation shelters during disasters, we believe our technology can make a significant contribution in enhancing their functionality and resilience.
Futoshi Kamiwaki
Born in 1960, Kamiwaki joined Sekisui Chemical Co., Ltd. in 1983. In 2011, he was appointed Executive Officer and General Manager of the Housing Company’s Planning and Administration Department. In 2015, he became Managing Executive Officer and General Manager of the Housing Company’s Product Development Department.
Since 2020, he has served as Director and Senior Managing Executive Officer, overseeing the Corporate Strategy Department, ESG Management Promotion Department, Digital Transformation Promotion Department, and New Business Development Department.
Let’s Share!
Thin, lightweight, and flexible solar panels known as Perovskite.
This technology might just give us a glimpse into the future of energy!
Share your Monthly JP pavilion and circulate your thoughts.
