Ricoh, European startups race to bring flexible power source to market this year
TOKYO -- A thin, flexible alternative to silicon-based solar cells is set to be produced in greater volumes, opening up more uses for renewable energy such as powering indoor smart devices.
Organic solar cells are made by printing photovoltaic material on plastic sheets and other bendable substrates. They are expected to cost half as much to make as silicon-based solar cells and are 100 times lighter, manufacturers say.
Unlike silicon cells, the conversion efficiency of organic solar cells does not drop when used indoors. Companies are zeroing in on that advantage to develop power sources for smart speakers, remote controls and sensors.
Among the companies staking out claims in this field is German startup Heliatek, which will begin mass production of organic solar cells as early as this year. Japan's Ricoh has plans to produce them on a smaller scale starting in fiscal 2023.
Practical versions of organic cells emerged in the 2010s. But their efficiency in converting light to electricity topped out at around 10% in experimental settings -- half the rate of silicon cells. This limited their use to low-power applications, such as some wearable devices.
Since then, thanks to improvement in materials, manufacturers say they are ready for mass production. Heliatek aims for annual output of roughly 600,000 sq. meters, with a potential to expand production in 2023 and 2024. Maximum production capacity will be 1.1 million sq. meters a year.
The German startup envisions the sheets covering concrete domed roofs, metal and glass, and other surfaces that cannot support heavy silicon-based panels.
The organic solar cells have a conversion efficiency of around 10%, but they can be used for two decades. Sales started on a trial basis last year at prices higher than those for silicon cells. The company says mass production has the potential of cutting costs by half.
Each square meter of organic cell weighs less than 2 kg, and the weight will be reduced further to less than 1 kg next year, the company said.
Heliatek is not the only company producing organic cells. Brazilian startup Sunew has produced over 10,000 sq. meters of organic solar cells so far for vehicle rooftops and other uses. The company sees electric vehicles as a potential application.
Sweden's Epishine, a pioneer in organic solar cells, put its miniature solar harvesting modules on the market in December. They have a conversion efficiency of 13% and a life span of about 10 years. The startup says the modules can be used for temperature and humidity controls, card readers and fire alarms.
Ricoh is starting small. The Japanese electronics company plans to produce 100 sq. meters of organic solar cells next fiscal year. That will be enough to power roughly 50,000 small smart devices.
The solar cells can be used for wearables and for sensors that monitor the safety of tunnels and bridges, according to Ricoh. The company plans to increase the output to tens of thousands of square meters in 2030.
Organic semiconductors from Japan's Kyushu University were combined with Ricoh's material technology to create a prototype. Deliveries have been made on a pilot basis since last year.
Ricoh's organic solar cells have a conversion efficiency of about 10% outdoors. "Their performance does not fall in indoor light," said a Ricoh representative.
The organic solar cells can be made using printing technology. Ricoh says mass production could reduce production costs to half that of silicon solar cells.
French startup Dracula Technologies is developing film-like organic solar cells that do not use expensive rare-earth metals. Mass production is slated to begin by 2024.
In 2020, Dracula Technologies raised 2.4 million euros ($2.57 million) from individual investors for capital spending. Conversion efficiency runs as high as 13% outdoors and the cells last about 10 years. The startup says it looks to set the global standard for thin organic solar cells.
Installed solar cell capacity could reach 14 terawatts worldwide in 2050, about 20 times the 739 gigawatts installed as of 2020, according to an estimate by the International Energy Agency. Solar energy will be responsible for 33% of all power generation in the middle of the century, up from just 3% in 2020, the IEA forecasts.
The global market for smart sensors is expected to reach $29.6 billion in 2026, analytics company MarketsandMarkets predicted last year, representing a 3.5-fold increase from 2021. The growth will be fueled by smart appliances and wearables.
Many smart devices are powered by single-use batteries that need to be replaced every one to two years. Silicon solar cells are not as efficient indoors, while perovskite solar cells -- a new low-cost, efficient and lightweight alternative -- only last a year or two.
Organic solar cells can be produced in different colors, making them easier to match with indoor furnishings. They also do not contain lead and other materials that pollute the environment.
Competition is intensifying as different types of solar cells hit the market. The global market for organic solar cells will grow fivefold from 2021 to 2035 to over $500 million, according to research company Fuji Keizai.
Companies have high hopes for organic solar cells given their potential for improvement. Estimates of the number of potential materials run to several hundred thousand, compared with just a handful for perovskite cells.
"We could see dramatic improvements in term of costs and conversion efficiency if a groundbreaking material is discovered," said Yutaka Matsuo, a professor at Nagoya University in Japan involved in research in this field.
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