Australian scientists smash solar cell efficiency record

[Mr Medved 39]

Australian scientists smash solar cell efficiency record

(I've been told coal efficiency is 40% (big power plants), so if it is possible to produce these types of solar cells affordably then coal has a bleak future.)

 

https://cosmosmagazine.com/technology/australian-scientists-smash-solar-cell-efficiency-record

 

Australian engineers have chalked up a world record for electricity conversion efficiency by solar cells of 34.5%.

 

The previous record, set by US company Alta Devices, was  24%. The result was verified by the US National Renewable Energy Laboratory.

 

Mark Keevers and Martin Green, of the University of New South Wales in Sydney, used a 28 square centimetre module, embedded in a prism, to split incoming sunlight into four bands, and a hybrid four-junction receiver to maximise the amount of electricity generated from each beam.

 

The Alta record was achieved using an 800 square centimetre module.

 

This record is for unfocused sunlight. The same men already hold another record (at 40% efficiency) for focused sunlight, in an experiment using mirrors to concentrate the light before splitting out various wavelengths.

 

“This encouraging result shows that there are still advances to come in photovoltaics research to make solar cells even more efficient,” said Keevers.

Mark Keevers with one of the spectrum splitting, four-junction mini-modules.

 

Green said this level of efficiency had not been expected for many years.

 

“A recent study by Germany’s Agora Energiewende think tank set an aggressive target of 35% efficiency by 2050 for a module that uses unconcentrated sunlight, such as the standard ones on family homes,” he said.

 

The record-setting UNSW mini-module combines a silicon cell on one face of a glass prism, with a triple-junction solar cell on the other.

 

The triple-junction cell targets discrete bands of the incoming sunlight, using a combination of three layers – indium-gallium-phosphide, indium-gallium-arsenide, and germanium. 

 

As sunlight passes through each layer, energy is extracted by each junction at its most efficient wavelength, while the unused part of the light passes through to the next layer, and so on.

 

A diagram of the spectrum-splitting, four-junction mini-module.

 

However, multi-junction solar cells of this type are unlikely to find their way onto the rooftops of homes and offices soon, UNSW cautioned in a press release, as they cost more to manufacture than standard crystalline silicon cells with a single junction.

 

Nevertheless, the spectrum-splitting approach is perfect for solar towers which use mirrors to concentrate sunlight which is then converted directly into electricity, the university said.

[AndersB 29]

It will probably be expensive to manufacture solar panels with grids of prisms.

 

Nanowires is another technology for using multiple light frequency spectra. A Swedish tech start-up company claim they have that kind of technology that allows for up to 27% efficiency and approximately US $0.05 per watt manufacturing cost.

http://www.pv-tech.org/news/nanowire-start-up-sol-voltaics-secures-us17-million-funding-round

 

Lots of activity on the photovoltaic scene. It will be interesting to watch the industry evolve.