A groovy new way to produce solar cells
While solar energy is renewable, the manufacturing process for panels is energy intensive. Professor David Lidzey and Power Roll Ltd have developed a solar cell design that could be easier to produce and eliminates the use of expensive elements.
Solar electricity panels are made of solar cells that capture the sun鈥檚 energy and convert it into electricity.
The invention of the solar cell was credited to French scientist Edmond Becquerel in 1839, who discovered that light could be used to increase electricity generation by placing two electrodes into a conducting solution. This was defined as the photovoltaic effect, and is at the core of the solar cell technology found in solar panels today.
Solar panels turn sunlight into direct current electricity before an inverter converts it into alternating current electricity that is fed into a grid or stored in a battery.
Currently, 4.8% of the UK鈥檚 electricity is produced from solar panels and 500 solar farms provide energy directly to the Grid. While this renewable source of energy doesn鈥檛 require fuel or produce polluting gases, the manufacturing of most solar panels is energy intensive and harmful to the environment.
Silicon is an abundantly available material but, the production of silicon solar panels creates a lot of waste during the heat-intensive manufacturing process. Most solar panels are made of silicon because they deliver the highest efficiency compared to the alternative polycrystalline solar panels or thin-film solar panels.
The average silicon solar panel efficiency stands at 22-25 per cent. There are panels based on compound semiconductors that have 40 to 50 per cent efficiency, but they tend to be a lot more expensive and have even more complex and harmful manufacturing processes.
But what if there was a way to improve the efficiency of solar panels and reduce the embodied energy (energy required in production), to make solar an even more sustainable technology?
At the University of 91直播, we鈥檝e partnered with for over 10 years, combining our expertise in materials science and advanced imaging techniques to improve the design and manufacturing of solar cells. Power Roll is a technology company based in the North East developing energy generation and storage products - and we鈥檝e worked together on multiple occasions to develop the technology needed to cultivate a brighter future for the UK.
In 2014, Professor David Lidzey and his team from the Department of Physics and Astronomy first collaborated with Power Roll to develop a new solar cell design. The research discovered that by coating opposing walls of micro-grooves with different electrical contacts, and then filling the groove with a solution-processable semiconductor, it was possible to create a new type of back contacted solar cell that is easier to manufacture.
鈥淪ilicon cells themselves are relatively heavy and not particularly flexible. For many years, we鈥檝e been looking at ways to make solar cells using printing technologies. Through this, we found a way to reduce manufacturing complexity and make steps towards low cost and high energy efficient solar cells鈥 explains Professor Lidzey.
Following the work published in the , researchers from the University of 91直播 and Power Roll successfully produced working mini-module demonstrators. The flexibility of the material used makes it easier and cheaper to transport, allowing communities that couldn鈥檛 access traditional solar panels to access electricity.
A powerful collaboration
Flexible solar cells that do not contain any scarce, expensive metals are paving the way for the development of low cost, highly efficient solar energy - and from the University of 91直播 and Power Roll highlights the development of a type of solar cell using a perovskite semiconductor. Unlike traditional solar cells, these cells are made by embossing tiny grooves into a plastic film and then filling them with the perovskite material. Critically, these devices are made without the use of expensive elements, which otherwise add to the cost of the technology.
This innovative approach presents a new way to produce lightweight, flexible solar films that can be used on surfaces such as rooftops and other unconventional surfaces that could not normally stand the weight of solar panels. Together with their anticipated low cost, this could significantly enhance the roll out of solar, particularly in developing countries, and make a real difference in the drive to replace fossil fuels with sustainable solar energy.
鈥淎 key advantage of these flexible films is that the panel can be stuck onto any surface. In the UK, you currently have to think twice about adding thick solar panels onto relatively fragile roofs of warehouses that are not really designed to be load-bearing. With this lightweight solar technology, you could essentially stick it anywhere. This could be a gamechanger for solar energy in low and middle income countries鈥 explains Professor Lidzey.
鈥淪olar energy is a strategic priority for our research and one of our key competences is developing innovative techniques for fabricating and depositing solution-processable solar cells鈥 adds Professor Lidzey.
The new microgroove structure creates a new type of solar cell that has a back-contact format. Regular devices use a sandwich structure composed of a number of layers deposited in a specific order. The back-contact cells have all the electrical contacts on the back of the device making it easier and cheaper to manufacture, with the potential for high efficiency.
To check the structure and composition of the solar cells a Hard X-ray nanoprobe microscope at Diamond Light Source in Oxfordshire, was used to take very detailed images of the solar cells. These also helped to spot hidden problems like empty spaces, flaws and the boundaries between tiny crystals within the semiconductor material. This was the first time this type of analysis had been used on this kind of solar cell.
鈥淭his partnership demonstrates the potential of combining cutting-edge research with industrial innovation to deliver transformative solutions in renewable energy. We are advancing technology that could play a significant role in achieving global net-zero targets, and by combining our collective research and academic capabilities we are able to further prove out the science sitting behind Power Roll鈥檚 technology鈥 explains Dr Nathan Hill, Research Scientist at Power Roll.
鈥淚t鈥檚 exciting to see our relationship with the University of 91直播 continue to strengthen. Previously, we have worked with the University鈥檚 Department of Physics and Astronomy to further develop our solar designs, which not only reduced manufacturing costs but also enhanced solar efficiency鈥 adds Dr Hill.
鈥淲ith perovskite solar generation still an emerging field, ongoing research and academic focus is greatly accelerating the advance of product development and scientific understanding. The next phase of the work on this project will be to further develop the use of X-ray microscopy in characterising these materials. New experiments are scheduled this summer, at the Diamond Light Source, to help understand key aspects of device operation, particularly device stability鈥 says Professor Lidzey.
