There’s great momentum in the race to develop renewable energy sources and replace our dependency on harmful fossil fuels. That’s good news as energy consumption is only projected to grow.
Solar power offers especially exciting potential as a clean and endless energy source. But solar energy companies face stiff competition from alternative sources that can produce power more cheaply.
To grow solar energy use, manufacturers are searching for ways to build more efficient and durable products for harnessing the sun’s power. That starts with using additives, such as boron, to enhance performance and support longer product lifespans.
What role does boron play in solar energy?
Boron is a versatile additive used in several solar energy products across multiple applications, including the most critical function: Converting sunlight into energy.
Solar panels are a widely used renewable energy technology. They are covered with photovoltaic (solar) cells that absorb energy from the sunlight and then convert that energy into electricity, which is then routed to the energy grid or a power storage unit.
In solar panels, boron is found in two critical components:
- Solar cells
- Glass panels
Boron doping in solar cells
The fundamental unit of a solar panel—the solar cell—is comprised of two layers of silicon (p-type and n-type). The junction between these layers is where electricity is generated and ultimately pushed to the energy grid.
While silicon itself is a strong and stable material, it’s a poor conductor. Therefore, manufacturers use a doping technique to enhance the p-type layer with boron and the n-type with phosphorous.
Doping creates a difference in the number of electrons each layer has—the n-type has more and p-type, fewer. After doping, manufacturers join these two layers together to create an electrical field, where one layer is negatively charged and the other, positively.
Once the cell is subjected to the sun, photons from the sunlight free the electrons in both silicon layers. When electrons reach the electric field, the field pushes them toward the top silicon layer and then forcefully directs them out of the solar cell to metal conductor strips to generate electricity.
Borosilicate glass solar panels
Glass is a special material that’s used for two purposes in solar panels:
- Sunlight transmission without absorption
- Providing an essential protection layer
Borosilicate glass has superior clarity and strength compared to other types of glass, making it a preferred choice for solar panel manufacturers.
Important glass qualities, clarity and transparency allow sunlight to hit the solar panel and directly pass through to the other side where solar cells generate energy.
A solar panel is comprised of hundreds of these solar cells. They must be protected against harmful weather such as hail or snowstorms, as well as temperature swings. With its lower thermal expansion coefficient, borosilicate glass withstands sudden changes in temperature, a quality that results in longer solar panel lifespan.
Unlike soda lime glass, borosilicate glass possesses little to no alkali elements. This reduces the risk of alkalis seeping out of the glass and negatively impacting the solar cells.
Solar water heaters
Borosilicate glass is also used in solar water heating systems. Borosilicate glass is the key component of a highly efficient type of solar collector called “evacuated tube collectors (ETC).”
An ETC system features two concentric borosilicate glass vacuum tubes, leaving a gap for air, creating a vacuum effect. This serves as both a great insulator to minimize heat loss and separates hot water from cold.
Boron in solar: Important considerations
For all applications and solar products, consistency and quality are top consideration including minimizing levels of impurities such as iron.
As a global leader in refined borates, U.S. Borax manufactures products that meet rigid quality thresholds, providing borates to solar energy companies with highly stable physical and chemical properties.
Depending on the process there are several factors to consider.
The Czochralski method is commonly used to dope the silicon wafers of a solar cell with small amounts of boron. Prior to melting silicon, manufacturers adjust the boron concentration (B2O3) in the raw material.
Either sodium or non-sodium borates can be combined with other raw materials to melt into borosilicate glass. Depending on a product’s requirements—whether it’s solar glass tubing or panel glass—the borate concentration will impact the finished product’s characteristics.
Want to know more?
Borates are used in a number of other sustainable energy products. Learn more about how borates power sustainability.