Silicon Solar Cell Design Reduces Thickness by 90%
Engineers at MIT have discovered a new technique for building silicon solar cells that can trap rays of light as effectively as conventional silicon solar cells, while reducing the thickness by 90 percent. Using a pattern of tiny inverted pyramids etched into the surface of silicone, more light can be absorbed than solid silicon surfaces that are 30 times thicker.
A large bulk of the cost of solar arrays lies in the highly purified silicon—as much as 40 percent. Now, researchers are finding ways to make solar cells of the future more efficient, inexpensive and as thin and light as possible. Today, MIT engineers have brought us one step closer to the future of photovoltaics. Think of it as the iPhone of solar cells—the bulkiness, efficiency and accessibility of both technologies have certainly come a long way since the 80s.
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The new findings are reported in the journal Nano Letters in a paper by MIT postdoc Anastassios Mavrokefalos, professor Gang Chen, and three other postdocs and graduate students, all of MIT’s Department of Mechanical Engineering.
According to Mavrokefalos, the method would enhance the efficiency of solar cells, no matter what the thickness.
Though other methods on the market have been employed to reduce cost of silicon, MIT's design would reduce the weight, which would also lead to savings in the installation process.
Using standard silicon-chip processing materials, the team reported that the indented pyramid texture is easy to fabricate. Two sets of overlapping laser beams used to create the dents are integrated into the silicon using lithography techniques. Potassium hydroxide is then used to burn parts of the surface not covered, and the crystal structure of the silicon sets the pyramid shape.
Thus far, the team has tested the surface of the silicon wafer. The next step will involve testing its efficiency as a photovoltaic cell comparable to traditional designs.
Supported under the US Department of Energy and the National Science Foundation, the project's potential impact is expected to be significant in providing an effective structure for photon management for enabling thin cells.
Major move forward for UK’s nascent marine energy sector
Although the industry is small and the technologies are limited, marine-based energy systems look to be taking off as “the world’s most powerful tidal turbine” begins grid-connected power generation at the European Marine Energy Centre.
At around 74 metres long, the turbine single-handedly holds the potential to supply the annual electricity demand to approximately 2,000 homes within the UK and offset 2,200 tonnes of CO2 per year.
Orbital Marine Power, a privately held Scottish-based company, announced the turbine is set to operate for around 15 years in the waters surrounding Orkney, Scotland, where the 2-megawatt O2 turbine weighing around 680 metric tons will be linked to a local on-land electricity network via a subsea cable.
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Described as a “major milestone for O2” by CEO of Orbital Marine Power Andrew Scott, the turbine will also supply additional power to generate ‘green hydrogen’ through the use of a land-based electrolyser in the hopes it will demonstrate the “decarbonisation of wider energy requirements.”
“Our vision is that this project is the trigger to the harnessing of tidal stream resources around the world to play a role in tackling climate change whilst creating a new, low-carbon industrial sector,” says Scott in a statement.
The Scottish Government has awarded £3.4 million through the Saltire Tidal Energy Challenge Fund to support the project’s construction, while public lenders also contributed to the financial requirements of the tidal turbine through the ethical investment platform Abundance Investment.
“The deployment of Orbital Marine Power’s O2, the world’s most powerful tidal turbine, is a proud moment for Scotland and a significant milestone in our journey to net zero,” says Michael Matheson, the Cabinet Secretary for Net-Zero, Energy and Transport for the Scottish Government.
“With our abundant natural resources, expertise and ambition, Scotland is ideally placed to harness the enormous global market for marine energy whilst helping deliver a net-zero economy.
“That’s why the Scottish Government has consistently supported the marine energy sector for over 10 years.”
However, Orbital Marine CEO Scott believes there’s potential to commercialise the technology being used in the project with the prospect of working towards more efficient and advanced marine energy projects in the future.
“We believe pioneering our vision in the UK can deliver on a broad spectrum of political initiatives across net-zero, levelling up and building back better at the same time as demonstrating global leadership in the area of low carbon innovation that is essential to creating a more sustainable future for the generations to come.”
The UK’s growing marine energy endeavours
This latest tidal turbine project isn’t a first for marine energy in the UK. The Port of London Authority permitted the River Thames to become a temporary home for trials into tidal energy technology and, more recently, a research project spanning the course of a year is set to focus on the potential tidal, wave, and floating wind technology holds for the future efficiency of renewable energy. The research is due to take place off of the Southwest coast of England on the Isles of Scilly