Printed Solar Cells for 1.3 Billion People: What Became of the Idea

3D Printed Solar Cells Could Provide 1.3 Billion People with Electricity

Printed solar cells are thin, flexible films that can be coated onto plastic or glass with printing machines instead of being cut from silicon wafers. In 2015 they were promoted as a cheap way to bring electricity to the roughly 1.3 billion people who then lived without it. The idea was sound in principle, but it was not really "3D printing", and a decade later the technology is still working through the same problems that worried researchers at the time: durability, lead content and the cost of the machines.

Below is what the original claim said, what it got right and wrong, and where printed perovskite solar power stands now.

Where the 1.3 billion figure came from

The story began at the World Conference of Science Journalists in Seoul in June 2015. At a session run by the Smart Villages Initiative, a project that studies off-grid energy for rural communities, speakers argued that solar film printed in large rolls could be shipped cheaply to places with no power lines. SciDev.Net reported the session on 10 June 2015 and repeated the widely used estimate that 1.3 billion people in developing countries had no electricity at all.

The argument was simple. Conventional panels are heavy, fragile and expensive to move to a village reachable only by river or dirt track. A roll of lightweight film, by contrast, can travel in a backpack. If the film could also be made locally, the savings would be even bigger.

What "printed" solar cells actually are

Despite the popular headline, these cells are not built layer by layer in a 3D printer. They are made with the same family of methods used to print newspapers and packaging: slot-die coating, blade coating, spray coating, inkjet and screen printing. A liquid "ink" containing the light-absorbing material is spread over a moving sheet, dried, and covered with further thin layers that carry the electric current. Industry calls this roll-to-roll production.

The light absorber that made the approach exciting is a class of materials called perovskites. The name comes from a natural mineral, calcium titanate, first described in the Ural Mountains and named after the Russian mineralogist Lev Perovski. Solar perovskites are not mined, though. They are synthetic compounds, most often containing lead, iodine or bromine and a small organic molecule, that share the mineral's crystal structure. That structure happens to be excellent at absorbing sunlight and moving electrical charge, and it can be made from solutions at low temperatures, which is exactly what printing needs.

A very young technology

Perovskites entered solar research only in 2009, when a Japanese team led by Tsutomu Miyasaka reported a cell with 3.8% efficiency. Within a few years laboratory cells passed 20%, a pace of improvement that took silicon decades. That rapid climb is the "from 3% to 20%" leap mentioned in 2015 reports. It is worth stressing that those record numbers came from tiny laboratory cells, usually made by spin coating, not from large printed sheets.

Checking the 2015 claims

Some details from the original coverage need correcting. Scott Watkins, then director of the overseas business unit of the Korean chemical firm Kyung-In Synthetic, was quoted saying a 10 × 10 cm film could produce "10-50 watts per square metre". Read carefully, that figure is modest. Full sunlight delivers about 1,000 watts per square metre, so 10 to 50 watts means an efficiency of roughly 1% to 5%, far below the 20% laboratory record. A film the size of a postcard (one hundredth of a square metre) would therefore yield well under one watt: enough to trickle-charge a phone or run a small LED, not to power a home.

The story also said silicon panels "need much sunlight" while printed films do not. In reality all solar cells produce less power in dim light. Some perovskite and organic films do perform relatively well in diffuse or indoor light, which is one reason they are being tested for sensors and small electronics, but they do not escape the basic physics.

The concerns raised in 2015 were accurate, though. The films were vulnerable to moisture, and because most perovskites contain lead, a damaged cell could leak small amounts of it. Kyung-In Synthetic and others were developing protective coatings, and Bernie Jones of the Smart Villages Initiative pointed to a very practical obstacle:

"Entrepreneurs we've engaged cannot afford to invest in the printing machines needed to produce cheap solar strips." — Bernie Jones, Smart Villages Initiative, as reported by SciDev.Net

He suggested that cooperatives, similar to farmers' cooperatives in Rwanda, might pool money for equipment and handle distribution.

How far perovskites have come

Efficiency has kept rising. According to the National Renewable Energy Laboratory chart cited on Wikipedia, single-junction perovskite cells reached about 27% by 2025, and cells that stack a perovskite layer on top of silicon (so-called tandems) have passed 34%. In January 2026, pv magazine reported that the Shenzhen start-up SolaEon had a 27.87% single-junction cell certified by China's National Photovoltaic Industry Metrology and Testing Center. The test device measured just 0.076 square centimetres, smaller than a fingernail, and the same report noted that large modules from the company had reached around 20.7%.

Printing has also improved. A 2024 study of fully roll-to-roll fabricated perovskite modules reported up to 15.5% for small cells and 11% for larger interconnected modules. That is respectable, yet still well behind the best laboratory devices, which shows how hard it is to keep quality high over metres of film.

The stubborn problems

Lifetime. Silicon panels are commonly guaranteed for 25 years or more. Perovskite layers can degrade with heat, light, oxygen and especially humidity, so sealing them well remains the central engineering task.
Lead. Tin-based alternatives exist, but their efficiency is much lower (around 10% in reported studies). Most research now focuses on encapsulation and recycling instead.
Scale and money. Even cheap printing lines need serious capital, the very point Bernie Jones made in 2015.

Energy access today

The good news is that the number of people without electricity has fallen sharply since 2015, mostly thanks to grid expansion and ordinary silicon solar products such as solar lanterns, home kits and mini-grids. According to the United Nations' SDG 7 progress figures, about 655 million people (8% of the world's population) still had no electricity in 2024. The gap is now concentrated in sub-Saharan Africa, which accounted for around 85% of those without access in 2023, mostly in rural areas.

In other words, the villages that 2015 headlines had in mind were reached mainly by cheap silicon, whose price collapsed faster than almost anyone predicted. Printed perovskite film has not yet played a major role there.

What to take from the story

The 2015 vision was not wrong, just early. Lightweight, printable solar film could still be useful where transport is the biggest cost, for example on tents, rooftops that cannot carry heavy panels, or portable chargers. If you see a headline promising that a new solar material will "power a billion people", it helps to ask three questions: How large was the tested cell? How long does it last outdoors? And who will pay for the factory? Those answers usually say more about the near future than any record efficiency figure.

For now, the most realistic role for perovskites is as a booster layer on top of silicon, squeezing more power from the same panel area. The cheap, printed, village-made solar strip remains a goal worth chasing.

Sources: SciDev.Net, 10 June 2015: Printed solar cells hold promise for unlit rural areas; Wikipedia: Perovskite solar cell; pv magazine, 28 January 2026: SolaEon's 27.87% perovskite cell; United Nations: Sustainable Development Goal 7. The story was first shared online by The Mind Unleashed in September 2015.

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COMMENTS

BLOGGER: 1

AromisFebruary 17, 2016 at 9:23 PM
Thin film solar cells are nothing new. CIGS, CIS, all been around and all to expensive and less efficient than silicon based modules. The same lack of roll to roll continuous production that has hampered the industry still exists. I am not sure how this thing will help a billion people. Want to help a billion people? Build cars that use inductive magnetic coupling by coils supplied under the roads and draw all the power from geothermal systems.