Magic solar milestone reached: UNSW claims 25 percent solar cell efficiency title

Oct 23, 2008
solar panels

University of New South Wales ARC Photovoltaic Centre of Excellence has reported the first silicon solar cell to achieve the milestone of 25 per cent effiency.

The UNSW ARC Photovoltaic Centre of Excellence already held the world record of 24.7 per cent for silicon solar cell efficiency. Now a revision of the international standard by which solar cells are measured, has delivered the significant 25 per cent record to the team led by Professors Martin Green and Stuart Wenham and widened their lead on the rest of the world.

Centre Executive Research Director, Scientia Professor Martin Green, said the new world mark in converting incident sunlight into electricity was one of six new world records claimed by UNSW for its silicon solar technologies.

Professor Green said the jump in performance leading to the milestone resulted from new knowledge about the composition of sunlight.

"Since the weights of the colours in sunlight change during the day, solar cells are measured under a standard colour spectrum defined under typical operational meteorological conditions," he said.

"Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green."

The recalibration of the international standard, done by the International Electrochemical Commission in April, gave the biggest boost to UNSW technology while the measured efficiency of others made lesser gains. UNSW's world-leading silicon cell is now six per cent more efficient than the next-best technology, Professor Green said. The new record also inches the UNSW team closer to the 29 per cent theoretical maximum efficiency possible for first-generation silicon photovoltaic cells.

Dr Anita Ho-Baillie, who heads the Centre's high efficiency cell research effort, said the UNSW technology benefited greatly from the new spectrum "because our cells push the boundaries of response into the extremities of the spectrum".

"Blue light is absorbed strongly, very close to the cell surface where we go to great pains to make sure it is not wasted. Just the opposite, the red light is only weakly absorbed and we have to use special design features to trap it into the cell," she said.

Professor Green said: "These light-trapping features make our cells act as if they were much thicker than they are. This already has had an important spin-off in allowing us to work with CSG Solar to develop commercial 'thin-film' silicon-on-glass solar cells that are over 100 times thinner than conventional silicon cells."

ARC Centre Director, Professor Stuart Wenham said the focus of the Centre is now improving mainstream production.
"Our main efforts now are focussed on getting these efficiency improvements into commercial production," he said.
"Production compatible versions of our high efficiency technology are being introduced into production as we speak."

The world-record holding cell was fabricated by former Centre researchers, Dr Jianhua Zhao and Dr Aihua Wang, who have since left the Centre to establish China Sunergy, one of the world's largest photovoltaic manufacturers.

"China was the largest manufacturer of solar cells internationally in 2007 with 70 per cent of the output from companies with our former UNSW students either Chief Executive Officers or Chief Technical Officers", said Professor Green.

Source: University of New South Wales

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User comments : 18

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ShadowRam
4.8 / 5 (8) Oct 23, 2008
So nothings changed. Just the standard changed, in how they measure efficiency.

itistoday
2.8 / 5 (5) Oct 23, 2008
I say... we all just take a shovel and start planting things.

They're nearly 100% efficient (take that human scientists!) and they even take care of the CO2 problem for us!

Go hug a tree.™
PieRSquare
4.9 / 5 (7) Oct 23, 2008
Seems like we're splitting hairs at this point in the game. Making them cheap should be a bigger priority. If they become the cheapest way to produce power then well see mass adoption.
ZeroDelta
1 / 5 (4) Oct 23, 2008
I guess evryone here would complain if fusion reactors reached their target efficiency
earls
5 / 5 (5) Oct 23, 2008
ZeroDelta, while I will concede this web outpost harbors a vast number of negative nancies, in this case, as ShadowRam pointed out, the only thing that has changed is the metric - not exactly what I call "progress."
barakn
5 / 5 (3) Oct 23, 2008
I say... we all just take a shovel and start planting things.

They're nearly 100% efficient (take that human scientists!) and they even take care of the CO2 problem for us!

Go hug a tree.™

No. Plants only convert 0.2% to 8% (depending on the plant and which scientist you ask) of solar energy into usable energy.
RFC
3 / 5 (1) Oct 23, 2008
This article is confusing. It says there was some tweaking of the standards, but it also suggests that there were improvements in cell design. Not sure of the actual effect of either.

deatopmg
3 / 5 (1) Oct 23, 2008
more PR stuff to get grant money. Cost effectiveness is a function of the lowest installed cost per watt x lifetime. If the most cost effective is at 1% conversion efficiency so be it.
Phaze
4 / 5 (1) Oct 23, 2008
need to be a delivered price of .15 to .2 to the house or from the roof. until they its cheaper to make coal clean
jeffsaunders
4 / 5 (2) Oct 23, 2008
Looks like most of us are on the same page visa vis the change from 24.7% efficiency to 25% efficiency without having to actually do anything.

Still I hope they are also working on ways of improving the collection of solar energy even if it does not involve silicon.

Why limit ourselves silicon solar panels when by broadening our horizons we open the door to much higher efficiencies?
itistoday
5 / 5 (3) Oct 23, 2008
No. Plants only convert 0.2% to 8% (depending on the plant and which scientist you ask) of solar energy into usable energy.


Hmm... You are correct. I apologize, I was remembering some article I had seen a while ago toting that figure, but it appears that either I misunderstood it or the reporting wasn't all that spectacular.

Here's some more info on it (which might explain where the 100% figure came from):

The primary reactions have close to 100% quantum efficiency (i.e., one quantum of light leads toone electron transfer); and under most ideal conditions, the overall energy efficiency can reach 35%. Due to losses at all steps in biochemistry, one has been able to get only about 1 to 2% energy efficiency in most crop plants. Sugarcane is an exception as it can have almost 8% efficiency. However, many plants in Nature often have only 0.1 % energy efficiency.


From: http://www.life.u...isit.htm
tigger
5 / 5 (2) Oct 23, 2008
I worked with the solar car challenge at UNSW... was funny because the university couldn't afford to use their own record breaking cells (UNSW has been a world leader in solar cells for a LONG time)... just too bloody expensive. For real world applications much better off with a larger number of cheaper cells to achieve a high overall output. The game at the moment should be entirely about getting cost down to an absolute minimum... we have vast areas of land suitable for the deployment of gargantuan arrays.
Modernmystic
2.5 / 5 (2) Oct 24, 2008
I worked with the solar car challenge at UNSW... was funny because the university couldn't afford to use their own record breaking cells (UNSW has been a world leader in solar cells for a LONG time)... just too bloody expensive. For real world applications much better off with a larger number of cheaper cells to achieve a high overall output. The game at the moment should be entirely about getting cost down to an absolute minimum... we have vast areas of land suitable for the deployment of gargantuan arrays.


LMFAO....just try to deploy those arrays on those "vast areas of land" and see how quickly the kooks crawl out of the wood work. You won't even have to file any official paperwork. Just let it get out that you're THINKING of doing something like that and all the NIMBY, Sierra Club, "save the flavor of the month species" people will have 100 friend to the court briefs filed and they won't stop until they get it appealed to the 9th circuit which will promptly grind into the dirt any plans you had to do with any land...especially if it's public land...
GIR
5 / 5 (4) Oct 24, 2008
We already have vast tracks of land available for gargantuan arrays that nobody will complain about us using... Cities

In the past several months I've noticed alot of articles showing advancements in cheap, durable, thin solar panels.

Here is one example. There are several others but I was too lazy to look them all up -.-
http://www.physor...388.html

If thin solar panel tech could be manufactured to be durable and cheap enough to be used in construction materials they could take a big chunk out of peak load. Efficiency wouldn't matter if they were cheap enough to form into shingles or as a skin on siding.

$/watt and storage technology is definately what will drive implementation of massive solar farms. However, researching low efficiency/cheap/practical solar panels for the masses could make its own contribution and shouldn't be over looked.
tkjtkj
5 / 5 (2) Oct 25, 2008
Rather than working to make them
cheap, they are doing quite the
opposite: making them more
complex ( = expensive by
definition!) Were available space
for arrays be limiting, yes,
complexity is needed. But space
IS available ... 9th circuit
be damned!

Velanarris
3 / 5 (1) Oct 26, 2008
They'd be far better off developing kintetic energy capture devices and integrating them into building structure and city infrastructure.
Soylent
2 / 5 (1) Oct 26, 2008
In the past several months I've noticed alot of articles showing advancements in cheap, durable, thin solar panels.


Cheaper solar cells isn't very useful unless installation and storage/transmissions similarly becomes cheaper.(swap storage for maintenance in case of solar thermal)
Lord_jag
1 / 5 (1) Oct 27, 2008

Cheaper solar cells isn't very useful unless installation and storage/transmissions similarly becomes cheaper.(swap storage for maintenance in case of solar thermal)


Solar doesn't need to be stored in "Grid-tied" systems and would relieve a lot of the dependency on transmission. People will make energy where it's needed (or relatively close to it. )

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