What are Organic Solar Cells?

Written-by

Janet Richardson

Reviewed-by

Richard Burdett-Gardiner

Updated on

Sep 29, 2024

What are Organic Solar Cells?

Organic solar cells are the third generation of solar cell technology and are also known as organic photovoltaic cells (OPV). These organic solar cells are incredibly powerful when it comes to absorbing light from the sun. They are able to harness larger amounts of sunlight than other solar cells which is one of the reasons why organic power is often considered to be the future of solar technology. Even the most efficient traditional solar technologies will not be able to compete with the almost limitless possibilities offered by organic solar power thanks to the exceptional properties it possesses. 

OPV is a solar cell technology that is rapidly increasing in terms of technological advancements and popularity. It has several advantages, including the fact that it is incredibly lightweight, can cover a much larger area, and also has low manufacturing costs. OPVs are thinly filmed solar cells that have the potential to store much larger amounts of solar energy than other solar technologies.

Organic solar cell technology has the potential to drive the industry forward, especially with new research and development making it possible for increased sustainability. 

Organic photovoltaic (OPV) cells are a type of solar cell that uses organic semiconductor materials to generate electricity from the sun. These organic cells, also known as plastic solar cells, are typically made up of carbon-based polymers. These polymer cells are flexible and semi-transparent solar cells that are used to create thin-film solar panels or even transparent solar panels. Most organic photovoltaic cells are polymer cells. This type of polymer solar cell uses a branch of organic electronics that deals with conductive organic polymers or small organic molecules, for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. 

Traditional solar panels use crystalline silicon to absorb light from the sun and generate electricity. Silicon solar cells are rigid and are used in rigid types of panels such as monocrystalline or polycrystalline panels.

Organic solar cells are a relatively new and exciting technology that when applied to the wider market could bring the cost of panels down even further. NextGen Nano, a UK-based high-tech company, has developed organic solar cell technology that can replace the rigid and opaque silicon substrates of traditional solar panels with thin, lightweight, and tuneable substrates based on fluorine-doped tin oxide (FTO). This technological advancement gives organic solar cells versatile functionalities and allows them to be integrated into nearly all surfaces such as windows, walls car roofs, and even portable electronics. 

Organic photovoltaic cells can convert solar energy into electrical energy at rates that are far more efficient than any other form of solar cell technology even the silicon cells which are found in the most widely used solar panels. If you find yourself interested in this form of solar technology and would like some information on pricing and installation, we are here to help you out. Simply fill in the no-obligation form on this page, and one of our professional installers will get back to you with offers and quotes. It’s free and only takes a minute to complete.

How do Organic Solar Cells Work?

Organic photovoltaics work like all solar cells do by converting sunlight into electricity at an atomic level.

Here are the four steps in the process:

Light absorption
The organic solar cell's active layer absorbs sunlight in the form of photons which are small particles of electromagnetic energy. 

Charge separation
The absorbed photons knock electrons loose from atoms which creates electron-hole pairs. An electric field in the active layer separates the electron-hole pairs. 

Charge collection
Electrodes, normally made of transparent conductive materials, collect the separated electrons and holes. 

Electrical output
The charge separation and collection processes result in an electrical output. 

How Efficient are Organic Solar Cells? 

Earlier versions of organic photovoltaic cells were only 11% efficient on average. However, organic solar cells have recently achieved efficiencies of up to 19.31% which is more efficient than the thin-film and transparent solar panels currently in use. These solar panels have an efficiency of between 7% to 13 %. Currently, monocrystalline solar cells are still more efficient than organic solar cells as they typically reach efficiencies of between 20% and 25%.

Despite being developed to a higher efficiency organic solar cells are not yet being manufactured on a large scale. 

There are still challenges with organic solar cells that need to be addressed. Organic solar cells degrade faster than inorganic silicon-based ones when exposed to the environment. This means they have a shorter lifespan than traditional solar panels which can last for 25 to 30 years. According to the National Renewable Energy Laboratory organic solar cells last less than 10 years at best. On top of the efficiency limitations and shorter lifespan, organic solar cells also have long-term reliability issues. 

Scientists are working to improve the efficiency and reliability of organic solar cells. Some of the areas that research is focusing on include improving the absorber material, Developing organic multijunction architectures, and Improving encapsulation and alternative contact materials. 

Are Organic Solar Cells more Environmentally Friendly?

Part of the UK’s plan to power up Britain with cleaner, cheaper, and more secure energy sources is to increase solar capacity by nearly fivefold to 70GW by 2035. Although solar panels have been a great success story on the path to net zero, there is an increasingly compelling need to deal with their environmental impact when it comes to end-of-life disposal and waste generation.

The adoption of solar panel technology has grown exponentially every year since the early 2000’s according to Statista. Taking into account the average usable lifespan of 25 to 30 years for solar panels, it is likely that we will soon see a sharp increase in the number of panels that need to be replaced and recycled. 

Back in 2023, the BBC published an article highlighting the lack of facilities specifically designed to process solar panels which could easily turn into a ‘waste mountain’. It was thought that this was probably because up to now there hasn’t been much to process. In the article, Ute Collier, deputy director of the International Renewable Energy Agency states: 

“By 2030, we think we’re going to have four million tonnes of scrap – which is still manageable – but by 2050, we could end up with more than 200 million tonnes globally.”

Interestingly, the world’s first facility dedicated to the recycling of solar waste was opened in June 2023.

There are problems when it comes to recycling traditional solar panels, especially those based on crystalline silicon. These solar panels have a complex structure made up of multiple layers including silicon wafers, glass, metal conductors, and encapsulants, requiring specialised, energy-intensive processes to disassemble and separate materials. Furthermore, some of the intrinsic components like lead and cadmium in soldering materials are hazardous which means that they require careful handling during recycling. 

This is where organic solar cells can play a part. The organic polymers that make up organic solar cells can be created with recyclability in mind. Valuable components can be recovered when some of the organic materials in these cells are broken down and reprocessed. Further to that, the solution-based manufacturing processes used for organic solar cells, such as printing or coating, allow for the deposition of thin layers on flexible substrates. Different layers can be separated and recycled more easily due to this characteristic.

Due to their structure, organic solar cells can also be compatible with already existing recycling methods developed for plastic films and other flexible materials. 

The recyclability of organic solar cells is still an active area for research and development and it’s important to note that specific recycling technologies and infrastructure have not yet been established for them. 

Ongoing research to improve the efficiency and stability of organic solar cells will hopefully in time lead to a more environmentally friendly and recyclable solar power solution being available. 

The Disadvantages of Organic Solar Cells

For the organic solar cells to match the performance of silicon solar cells, and even exceed it, the donor and acceptor materials that are used in an OPV must have excellent extinction coefficients (which refers to several differing measures of the absorption of light in a medium), high stability, and a sturdy film structure. 

Organic solar cell technology is still in the early stages of its development phase when compared to silicon solar cells. There are still some problems that need to be resolved with the technology. Various new materials, construction models, and technological tweaks are currently being performed to try and rectify these problems.

The two main disadvantages of organic solar cells are that they are still less efficient than silicon solar cells and they have a much shorter lifespan. Their shorter operational lifetime means that they are not yet good candidates for long-term, large-scale projects.

Here is a fuller account of the disadvantages of organic solar cells:

• Lower efficiency when compared to other solar cell types. Although recent developments have increased the efficiency of organic solar cells to 19.3%, in real-world conditions they are typically around 10-12% efficient. Meanwhile, silicon solar cells will typically reach an efficiency of between 20% and 25%. One reason for the lower efficiency of organic solar cells is recombination, a process where electrons lose energy and fall back into an empty hole state. Another reason is the thickness that is required to absorb enough light. A polymer layer needs to be at least 100 nanometers thick which means that only a small fraction of excitons can reach the interface at this thickness. 
• Shorter lifespan. The operational lifetime of organic solar cells is far shorter than that of traditional solar cells. This is because organic materials degrade at a much faster rate when exposed to the environment.

 Are Organic Photovoltaics Commercially Available?

Though organic solar cells are not yet commercially available there are a few manufacturers who are producing them and using them in pilot projects.

Heliatek, Nanoflex, and Sunew are three companies that manufacture organic solar cell film, which can be applied to building facades or glass. These companies are marketing their products for use in commercial or public buildings.

Epishine and Dracula Technologies are producing small printed organic solar cells that have been designed to power small home devices such as remote controls. 

However, most of these companies aren’t selling their products to the wider public as of yet. It’s probably going to be a few years before organic solar cells become widely available. 

Cost of Organic Solar Cells

Today, only a small amount of power is generated by solar cells across the globe. The conversion of energy from the sun into electricity and heating for our homes and businesses has still not reached as many homes as we would like. A lot of the reason for this is that solar-powered technology is still too expensive for everyone to benefit from it. Crystalline silicon is the primary material used in solar cells, and this is an expensive material that doesn’t help the consumer price of panels. Plus, the efficiency level of this is only averaging around 10%.

When we consider this, along with the cost of installation, panel support, wiring, and DC to AC converters, the price of solar cells really starts to rise. In addition to this, the lifespan of a solar panel is approximately 25-30 years, so a new one would have to be installed after this time. Organic solar cells could really be the next step when it comes to the development of solar technology. 

It is hoped that the new technology will make solar panels more widely affordable in the future so that more homes can benefit from solar energy. This is due to the cost reduction of cell manufacture as they are cheaper than silicone ones. Organic solar cell technology may be new and going through a lot of further research and development, but the estimated cost of manufacture for purely organic cells will range between £30 and £90 per square metre. That’s already a lot cheaper.

Future of Organic Solar Cells

Much of the research and development in organic solar cells is concentrated on improving their efficiency and long-term stability. These two aspects are currently preventing organic cell technology from going out to the wider market. 

The present limitations in organic cell technology mean that it may take a few more years before solar panels created with organic solar cells can hit the market. If you’re interested in solar, we would advise looking at traditional silicon solar panels for the time being to lower your electricity bills and reduce your carbon footprint.