Ultra-thin spray-on solar cells to bring cheap green energy to the masses

Scientists have developed low-cost spray-on solar cells that could result in a dramatic drop in the price of solar electricity.

Designed to be applied using a method similar to car paint, the cells could be easily mass produced, giving solar power the chance of ubiquity. The spray technique also results in very little waste, which helps to keep manufacturing costs low.

If the technique takes off we could see solar cells built into everything from cars to clothes, leading to a move away from centralised power generation.

The cells are made from a rival material to market-dominating silicon: perovskite. Although only recently adopted for use in solar cells, the material is gaining popularity due its low price and energy costs.

“There is a lot of excitement around perovskite-based photovoltaics,” explained Professor David Lidzey, lead researcher from The University of Sheffield Department of Physics and Astronomy.

“Remarkably, this class of material offers the potential to combine the high performance of mature solar cell technologies with the low embedded energy costs of production of organic photovoltaics.”


The design of the cells is similar to organic equivalents, but with better performance.

“What we have done is replace the key light absorbing layer – the organic layer – with a spray-painted perovskite,” explained Lidzey. “Using a perovskite absorber instead of an organic absorber gives a significant boost in terms of efficiency.”

Although not quite as high as silicon, the efficiency levels of perovskite cells are far better than their organic counterparts.

“The best certified efficiencies from organic solar cells are around 10%,” said Lidzey.

“Perovskite cells now have efficiencies of up to 19%. This is not so far behind that of silicon at 25% – the material that dominates the worldwide solar market.”

At present the team have only achieved 11% efficiency but believe that with further research this can be improved.


The study itself, however, has moved ultra-thin solar cell technology far closer to mass production.

“This study advances existing work where the perovskite layer has been deposited from solution using laboratory-scale techniques,” said Lidzey.

“It’s a significant step towards efficient, low-cost solar cell devices made using high volume roll-to-roll processing methods.”

Lidzey argued that this solar technology would become increasingly key in power generation.

“I believe that new thin-film photovoltaic technologies are going to have an important role to play in driving the uptake of solar-energy, and that perovskite-based cells are emerging as likely thin-film candidates,” he said.

Images courtesy of Alex Barrows, Lucy Pickford and Jon Griffin via The University of Sheffield.

Looking for life: NASA announces Mars 2020 rover instruments

NASA has announced the instruments it has selected for its Mars 2020 rover, and the focus is on detecting signs of life and developing technology for a human mission to the red planet.

The Mars 2020 rover is a follow-up to Curiosity, the currently-deployed rover that has excited many with its robotic selfies and amusing tyre shapes. Mars 2020 will have a very similar design to Curiosity, but will feature more advanced instruments that its predecessor.

In an announcement from NASA’s Washington headquarters entitled “Mars 2020 Rover: Studying the Red Planet as Never Before”, the agency outlined the instruments it had selected to be part of the roving laboratory.

As part of the announcement, John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate, discussed how great it was that Curiosity – Mars 2020’s predecessor – found that Mars had previously seen life-suitable conditions.

“The science behind Mars 2020 is really going to extend that,” he said.


Out of the 58 proposals that the agency received, NASA selected seven instruments to feature on the final rover.

Most exciting of these is MOXIE, a system designed to break apart Mars’ CO₂-laden atmosphere to produce oxygen.

Of all the technologies, this bears the most significance for future manned missions, as it could form the basis for a technology to enable humans to breathe on the planet, and one day even provide air for a human colony.

“This is a real step forward in helping human exploration on Mars,” explained Michael Meyer, lead scientist for the Mars Exploration Program.

Among the other technologies selected for Mars 2020 is Mastcam-Z, an upgraded camera that features a zoom for accurate terrain plotting and a weather station named MEDA that will provide clear data about dust levels and how well MOXIE is working.


Mineral and organic detection, however, covered the bulk of the instruments, with the hope that Mars 2020 will find the long hoped-for evidence of life on the red planet.

Among the instruments designed for this purpose was SuperCam – an upgraded version of Curiosity’s Chemcam with the ability to indentify minerals – SHERLOC – a mineralogy and organics detector – and PIXL, an arm-mounted sensor head that provides detailed mineralogy at the scale of microbial life.

The set is rounded off by RIMFAX – a radar imager that will provide the first subsurface images of Mars.

For Meyer, the value of the instrument selection is in how they work together.

“It’s how they play well together,” he said. “No measurement such as elemental chemistry is only done by one instrument. They overlap, they complement each other”

By having instruments use different methods to achieve the same results, the rover should provide robust and reliable data for future missions.

Images courtesy of NASA.