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Polymers could be key in affordable uptake of solar in homes and office buildings

Polymers could be key in affordable uptake of solar in homes and office buildings

We’re used to seeing massive solar panels strapped to the roofs of houses and office buildings, but a Victoria University lecturer says a process that incorporates solar cells into roofing materials could serve us better. According to Dr Justin Hodgkiss, these cells could provide all the energy used in a home or office building in New Zealand, at a more affordable option. 

Hodgkiss, a lecturer at the School of Chemical and Physical Sciences, said conventional solar cells use silicon to absorb light and convert the energy into electricity. But processing silicon into a working solar cell is very expensive, with the high costs limiting the uptake of the technology by consumers. 

Hodgkiss is one of a number of local and international scientists who are investigating an alternative option of making solar cells from polymers or plastics. They are building on the work of Nobel Prize winning New Zealand scientist and Victoria alumnus Alan MacDiarmid who discovered the electronic conductivity of polymers. 

Hodgkiss said the major advantage of using polymers is that they can be dissolved to make an ink and then printed in sheets. 

“That opens the possibility of making them quite cheaply. We might even be able to use existing machinery—in Australia, they are experimenting with printing polymer solar cells on the same presses used to print money.” 

The resulting solar cells would have a few layers made up of films of an active polymer sandwiched between transparent electrodes. 

“It sounds complicated but it’s not very different from a potato chip bag,” he said. 

Polymer solar cells are currently less efficient than those using silicon but that is changing. 

Hodgkiss said that when he first delved into the field four years ago, polymer solar cells had a power conversion efficiency of four percent. Now it’s at eight percent, something Hodgkiss described as a “steep trajectory”. 

He estimates that if every New Zealand rooftop was covered in a material containing a 10 per cent efficient solar cell, New Zealand’s energy needs would easily be met. 

To support him in his investigation, Hodgkiss has been awarded a Rutherford Discovery Fellowships providing financial support of $160,000 per year over five years.