A team of researchers from China and Australia has developed a new type of solar cells that are thinner than a sheet of paper and can be bent into a roll. These solar cells are made of silicon, the most common material for solar energy conversion, but they have a novel design that reduces their thickness and improves their efficiency.
How thin are these solar cells?
The solar cells developed by the team are only 50 micrometers thick, which is about the same as a human hair or a sheet of A4 paper. To achieve this, the researchers used a technique called epitaxial growth, which allows them to grow a thin layer of high-quality silicon on top of a cheaper substrate. This way, they can reduce the amount of silicon needed for the solar cells, and also make them more flexible and lightweight.
How efficient are these solar cells?
One of the challenges of making thinner solar cells is that they tend to lose some of their power conversion efficiency (PCE), which is a measure of how much sunlight they can turn into electricity. The team claims that they have overcome this problem by optimizing the charge transport and separation in the thin silicon layer. They report that their solar cells have a PCE of over 26%, which is higher than the average PCE of commercial silicon solar cells, which is around 20%.
What are the applications of these solar cells?
The team says that their thin and flexible solar cells have many potential applications, especially in areas where conventional solar panels are not suitable or cost-effective. For example, they can be used on curved surfaces, such as satellites, drones, or wearable devices. They can also be rolled into a film, which makes them easier to transport and deploy. The team is currently working on developing portable and flexible solar cells that can be used for various purposes.
How does this compare to other solar cell technologies?
There are many types of solar cells that use different materials and methods to convert sunlight into electricity. Some of the most common ones are:
| Type | Material | Thickness | PCE | Advantages | Disadvantages |
|---|---|---|---|---|---|
| Crystalline silicon | Silicon | 200-300 micrometers | 15-25% | High efficiency, long lifetime, abundant material | High cost, rigid, heavy, requires high temperature and energy for fabrication |
| Thin film | Cadmium telluride, copper indium gallium selenide, amorphous silicon, etc. | 1-10 micrometers | 10-20% | Low cost, flexible, lightweight, easy to fabricate | Low efficiency, short lifetime, scarce or toxic materials |
| Perovskite | Organic-inorganic hybrid compounds | 0.5-1 micrometers | 10-25% | High efficiency, low cost, tunable bandgap, easy to fabricate | Low stability, moisture sensitivity, scalability issues |
| Organic | Organic polymers or molecules | 0.1-1 micrometers | 5-15% | Low cost, flexible, lightweight, easy to fabricate | Low efficiency, short lifetime, degradation issues |
The solar cells developed by the team are a new type of crystalline silicon solar cells that combine the advantages of high efficiency, flexibility, and low material usage. They are thinner than most thin film solar cells, and have a higher PCE than most perovskite and organic solar cells. They are also more stable and environmentally friendly than some of the other solar cell technologies.
