A new device is able to take in sunlight, carbon dioxide and water to create a new carbon-neutral fuel without any outside source of electricity, its developers claim.

University of Cambridge experts behind the device say it uses a form of 'artificial photosynthesis' - the process used by plants to convert sunlight into energy.

The device is based on an advanced 'photosheet' technology and converts sunlight, carbon dioxide and water into oxygen and formic acid - a storable fuel.

This type of fuel can be either used directly in specially developed generators or by converting it into hydrogen, according to the Cambridge team. 

The wireless device could be scaled up and used on energy 'farms' similar to solar farms, producing clean fuel using nothing but sunlight and water as its inputs.

Harvesting solar energy to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and transition away from fossil fuels, experts claim.

However, it is challenging to produce these clean fuels without unwanted by-products that are costly and complicated to remove.

'It's been difficult to achieve artificial photosynthesis with a high degree of selectivity, so that you're converting as much of the sunlight as possible into the fuel you want, rather than be left with a lot of waste,' said first author Dr Qian Wang.