Boron in solar energy

What is boron and how is it used in solar energy?

An essential material for a low-carbon future

Last updated: 5 October 2023


To meet global needs, we need to use energy more efficiently and make the most of the energy resources we have, now and in future.

Manufacturers are searching for ways to build more efficient and durable solar energy products. Additives like boron can enhance performance and support longer product lifespans.

What is boron?

Boron is essential to plant growth, so it’s used in fertilisers, but also high-tech applications, such as heat-resistant glass for smartphones, materials for renewable energy – for both wind and solar projects, wood protection and fiberglass insulation. Crystallised salts that contain boron are called borates.

California and Nevada are particularly rich in borate deposits. We started mining in the area more than 150 years ago first in Death Valley and then moving, in 1927, to Boron, California. Today, our California operations, in the Mojave Desert, supply approximately 30% of global demand for refined borates.

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 it 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:

  1. Solar cells
  2. Glass panels

Boron in solar cells

Solar cells are the parts of solar panels that transform light into electricity. These are made of 2 layers of silicon: p-type, which has a positive charge, and n-type, with a negative charge. The magic happens in between these layers – electricity is generated and ultimately pushed to the energy grid.

While silicon itself is strong and stable, it’s a poor conductor. So manufacturers add other materials to the silicon to change its properties and improve its conductivity. In solar cells, boron is added to the p-type silicon layer and phosphorous to the n-type layer.

Adding these materials to the silicon, also known as doping, creates a difference in the number of electrons each layer has – the n-type has more and the 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 exposed 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.

Boron in solar cells
Boron is an essential ingredient that helps solar panels generate electricity from sunlight.

Borosilicate in glass cover for solar panels

Glass is used for 2 purposes in solar panels:

  1. Sunlight transmission without absorption
  2. Providing an essential protection layer

Borosilicate glass – glass that’s made using borates – is clearer and stronger compared to other types of glass, making it a preferred choice for solar panel manufacturers. Clarity is important because the clearer the glass, the more sunlight that hits the solar panel and directly passes through to the other side where solar cells generate energy.

Solar panels must also be strong enough to withstand harmful weather such as hail or snowstorms, as well as temperature swings. Because of its properties, borosilicate glass can tolerate sudden changes in temperature, leading to longer lasting panels. And unlike soda lime glass, borosilicate glass possesses few to no alkali elements. This reduces the risk of alkalis seeping out of the glass and negatively impacting the solar cells.

Boron in solar glass panels
Glass made using borates is clearer and stronger than other types of glass, making it well-suited to solar panels.

Banner image: Cavan Images via Getty Images

Boron in 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 minimise heat loss and separates hot water from cold.

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