New Tin-based Solar Cells Trap Heat 1,000 Times Longer, Could Beat 33% Limit (interestingengineering.com) 42
Could this push solar cell efficiency beyond the theoretical 33% limit? Interesting Engineering reports:
Researchers at the University of Groningen in the Netherlands found that tin-based perovskite solar cells can slow heat loss from high-energy "hot electrons..."
When sunlight strikes a panel, photons jump-start electrons into action. The most energetic photons create super-charged hot electrons... [but] in fractions of a trillionth of a second, these high-energy particles rapidly cool, dumping their bonus energy as waste heat before ever leaving the solar cell... In collaboration with Maria Antonietta Loi, professor of Photophysics and Optoelectronics, the team created an experimental setup. Using a specialized solar cell material called tin-based perovskite, Loi's lab performed a feat many thought impossible: she slowed the heat loss down by a factor of 1,000.
Suddenly, the extra energy lingered for nanoseconds instead of vanishing in picoseconds... To solve the puzzle, Koster and PhD student Tim Faber built digital simulations to peel back the quantum layers. And discovered a surprising double-action mechanism at work... The simulations matched the exact nanosecond delay observed in the lab... These specialized materials could be used to build a new generation of super-efficient solar cells.
Tin-based metal halide perovskites are non-toxic, eco-friendly crystalline materials for high-performance solar energy conversion... The material possesses an unusually low electron mass. As a result, electric charges move quickly and retain extra thermal energy for extended periods. This combination of broad light absorption, efficient charge movement, and prolonged energy retention makes these materials prime candidates for next-generation solar panels.
"There are many other questions that still need answers," the team said in their announcement, "but in theory, this discovery could allow the creation of more efficient solar cells, beyond the theoretical limit of 33 percent."
Thanks to long-time Slashdot reader fahrbot-bot for sharing the article.
When sunlight strikes a panel, photons jump-start electrons into action. The most energetic photons create super-charged hot electrons... [but] in fractions of a trillionth of a second, these high-energy particles rapidly cool, dumping their bonus energy as waste heat before ever leaving the solar cell... In collaboration with Maria Antonietta Loi, professor of Photophysics and Optoelectronics, the team created an experimental setup. Using a specialized solar cell material called tin-based perovskite, Loi's lab performed a feat many thought impossible: she slowed the heat loss down by a factor of 1,000.
Suddenly, the extra energy lingered for nanoseconds instead of vanishing in picoseconds... To solve the puzzle, Koster and PhD student Tim Faber built digital simulations to peel back the quantum layers. And discovered a surprising double-action mechanism at work... The simulations matched the exact nanosecond delay observed in the lab... These specialized materials could be used to build a new generation of super-efficient solar cells.
Tin-based metal halide perovskites are non-toxic, eco-friendly crystalline materials for high-performance solar energy conversion... The material possesses an unusually low electron mass. As a result, electric charges move quickly and retain extra thermal energy for extended periods. This combination of broad light absorption, efficient charge movement, and prolonged energy retention makes these materials prime candidates for next-generation solar panels.
"There are many other questions that still need answers," the team said in their announcement, "but in theory, this discovery could allow the creation of more efficient solar cells, beyond the theoretical limit of 33 percent."
Thanks to long-time Slashdot reader fahrbot-bot for sharing the article.
Re: thin film solar panels want their attention ba (Score:2)
I believe he is thinking of
"cost no more than printing a plastic sheet or a postage stamp"
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Yeah, but that was always a dumb idea, and it was always a minority position. Also we've know exactly why we can't have solar panels like that since [before] former thin film printed panel darling Nanosolar closed their doors in 2013: Microcracks develop in the protective plastic layers on thin film flexible solar panels and let in moisture which spoils the panel. You can make a relatively long-lived plastic solar panel if you don't want it to flex much, but it doesn't save much money in the end so that's d
Re:thin film solar panels want their attention bac (Score:5, Informative)
Um, have you looked at a graph of PV price trends [ourworldindata.org]?
And remember: that vertical axis is a logarithmic scale.
As for "the price of a lollypop per square meter", that's literally the first time I've ever heard that phrase, but okay, I'll bite. If by "lollipop" you mean retail prices for one of those big lollies [amazon.com], they're like $11 on Amazon on average. PV wafers are about $0,045/W [trendforce.com]. At a typical ~250W/m, that's like.... $11. Yes, a square meter of PV wafers is about the cost of a lollipop! Yes, integrating them into whatever panels or other solar device increases cost over the raw wafers, but we very much are "on the order of lollies".
Perovskite thin films (Score:5, Informative)
The perovskite semiconductors here are a very different technology than the old thin photovoltaics. They have the potential to be much more efficient, and the deposition techniques are cheap and comparatively low-tech
Whether they can succeed in simultaneously be highly-efficient, resistant to degradation in the environment, and still be low cost is the subject of a lot of work. We'll see.
They were supposed to be manufactured for the price of a lollypop per square meter back in the '90s.
To be more specific, the target back in the '80s and '90s was clearly articulated as being fifty cents per watt (where "per watt" meant, when illuminated at standard conditions of 1 kW/square meter.) Silicon photovoltaics can now be purchased at 12 cents per watt. [techspot.com] In today's dollars. They not only hit the target, they blew it away.
The reason the thin films of the '80s and '90s lost was not that they were bad, but that silicon simply outcompeted them.
So forgive my skepticism regarding new breakthroughs.
I have some amount of skepticism too. Nanosecond lifetimes of hot electrons are amazing, but to date there's no way for turning hot electrons into electrical energy*. So they'd essentially have to invent a technology from scratch.
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*(thermoelectrics convert hot electrons into usable energy, of course, but there not just the electrons, but the whole lattice is hot. And the efficiency is worse than a solar cell).
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Your last sentence... I was just about to post something similar... far as I remember, heat doesn't generate electricity in PV cells... it might even hurt their efficiency, but you beat me to it.
Now... you could route a water line behind the PV cell, and that'd give you warmer (depends on conditions) water (and might help cool the PV cells which might help their efficiency).
Hot electrons [Re:Perovskite thin films] (Score:4, Informative)
I have some amount of skepticism too. Nanosecond lifetimes of hot electrons are amazing, but to date there's no way for turning hot electrons into electrical energy*. So they'd essentially have to invent a technology from scratch.
--
Your last sentence... I was just about to post something similar... far as I remember, heat doesn't generate electricity in PV cells... it might even hurt their efficiency, but you beat me to it.
Correct on both, in fact heat decreases efficiency of PV cells (thermal dark current is opposite to photovoltaic current). However, keep in mind that "hot electrons" aren't exactly hot in the sensible-heat sense-- it means that the electrons are in a high-energy state well above the bandgap of the semiconductor. The solar photons come in at an equivalent temperature of 6000K, and all of that energy gets transferred to the minority-carrier electrons, but they quickly shed their excess energy (by transferring energy to the lattice and to other electrons or holes) and relax to the edge of the conduction band (or, ~kT above it). So, using "hot electrons" means somehow finding a way to transfer energy out of the highly-excited initial state immediately after photon absorption, rather than the relaxed quasi-equilibrium state of the conduction band.
So, there's energy there, and in principle it could be used. It's just going to take a new approach to use it. I can't think of a way to do that without adding junctions, and then you end up essentially just re-inventing the multi-junction solar cell.
Now... you could route a water line behind the PV cell, and that'd give you warmer (depends on conditions) water (and might help cool the PV cells which might help their efficiency).
Yes, but of course now you're harvesting the sensible heat, not the hot electrons. This can be useful, if you need low-grade heat.
Re:Perovskite thin films (Score:4, Interesting)
you could route a water line behind the PV cell, and that'd give you warmer (depends on conditions) water
"Hot electrons" doesn't mean the panel is hot. In fact, that's the point of this research. They found a way to slow the transfer of energy from the electrons to the crystal lattice. The longer you can keep it in the electrons, the more opportunity you have to convert it to electricity instead of heat.
If you just want to convert sunlight to heat, that's easy. A piece of black plastic works great. That's how solar water heaters work, and they already have efficiency way above 33%. Converting any kind of energy to heat is easy, because that's where it's going eventually anyway. Preventing it from turning into heat is what's hard.
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Those cells/panels exist, too. They are called PVT. https://en.wikipedia.org/wiki/... [wikipedia.org]
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price of a lollypop per square meter back in the '90s. To be more specific, the target back in the '80s and '90s was clearly articulated as being fifty cents per watt (where "per watt" meant, when illuminated at standard conditions of 1 kW/square meter.) Silicon photovoltaics can now be purchased at 12 cents per watt. [techspot.com] In today's dollars. They not only hit the target, they blew it away.
Calculating this in my head while trying to adjust for inflation is a bit of a trip. Simple calculations but so many marginal ranges.
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They were supposed to be manufactured for the price of a lollypop per square meter back in the '90s.
The price per square meter now is a fraction of what it was.
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Lollypops aren't cheap. Ask your sister what she had to do for the one she's got.
This isn't the issue. (Score:5, Informative)
To be clear: none of this is the reason why lead has been winning over tin. Unfortunately, the Sn+2 is extremely prone to oxidizing to Sn+4 even under trace oxygen or moisture contamination, and tin perovskites are extremely vulnerable to crystal defects, while lead perovskites aren't. It's unfortunate, but that's the way it is.
Unfortunate. (Score:4, Insightful)
Re:Unfortunate. (Score:5, Insightful)
And then people get angry about being mislead and assume everything is an attempt to mislead and that technology in a given field isn't advancing, wherein reality it continues to advance in the background. But rarely in any of the flashy "New Neato Gamechanger Breakthrough!" ways that attract tech journalists. It advances by ideas that, through long, hard slogs, often behind closed doors inside companies, slowly mature from "this kinda works" to "we can actually do this at scale".
Re:Unfortunate. (Score:4, Interesting)
and the answer is almost always "No."
Until it is suddenly "Yes". Pretty much everything you have around you today at one point was the subject of one of these research articles that people thought could never be mass produced. Hell I remember people saying colour LCD panels could never scale beyond a few pixels and that work in a lab was useless.
Re: (Score:2)
With solar it's more about the economics. PV is highly cost optimized so even if the new tech can scale up, it has to also be extremely cheap.
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Nope the answer is not nearly always "no".
It is just so that not on all break throughs anyone is interested in investing the time and money to make it mass market ready.
In this case however: it is already ready. There is one UK company doing it, I think one Canadian, too. And: dozens of Chinese companies.
Great, but... (Score:2)
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Re: Great, but... (Score:2)
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Current batteries are basically "painted".
Still with continued "research" and development, the last 100 years never was a glimpse of a chance to have batteries like we have them right now. The manufacturing technology - and material science - was simply not there.
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let me charge my flux capacitor with some trash and then i can answer that...
perovskite sucks (Score:2)
Perovskite panels only last a few years... normal mono panels have an order of magnitude longer service life.
Re:perovskite sucks (Score:5, Informative)
This was true of some pilot installations, but accelerated aging [nih.gov] of modern perovskite panels suggest much closer to silicon, and some have passed the same IEC standards as silicon panels.
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This was true of some pilot installations, but accelerated aging of modern perovskite panels suggest much closer to silicon, and some have passed the same IEC standards as silicon panels.
It would be nice if it worked. Perovskite has been nothing but disappointment for years. I'm not sure I buy lab aging tests because moisture infiltration is what does these things in. When someone sells them with a 20-30 year warranty it will be good enough for me.
Re:perovskite sucks (Score:5, Interesting)
https://www.photoncrystal.com/... [photoncrystal.com] gives a 10 year warranty on workmanship defects, and a 25 year warranty on the rated output (no lower than 85% of the initial output after 25 years). They give less warranty about how the curve looks than e.g. this company for traditional panels [jasolar.com], but other than that it seems pretty comparable.
Theoretical max efficiency of 33% ? (Score:2)
I hate finding out about limitations of by seeing a casual mention of those limitations by someone pushing an improvement.
Many many long years ago (Score:2)
Our textbooks proved conclusively that there was an absolute limit for solar panels of about 11% conversion.
The theoretical Max efficiency of 33% is good - right up until somebody comes up with a new Theory.
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I certainly wasn't privy to research papers at that point in time, I suppose it's possible the textbook authors weren't either.
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I was in an impoverished school still using textbooks that were published sometime in the 70's, and this "11%" rule of thumb rings a bell to me too. For what it's worth, I recall learning around the same time that the total energy conversion rate of the typical internal combustion engine being a mere 24%.
Re: Many many long years ago (Score:2)
Wow you recall a specific percentage well over half a century ago? Pray tell do you remember the name of the textbook and the edition or is that lost to time?
"Could" (Score:2)
Could a woodchuck chuck how much wood if a woodchuck could chuck would?
Solar-powered + STEAM-powered (Score:2)
they should use the heat from solar panels to concurrently use the heat generated / captured to push steam turbines.
Re: (Score:2)
nuclear to steam works pretty well too, skipping the whole light transmission and capture.
Solar (Score:2)
33% is more than enough to power the world without blanketing every inch in solar panels.
Love new technology, always have, but these kinds of advances pale in comparison to JUST PUTTING PANELS ON.
My house is a tiny, tiny (60sq m.... yes 60) house. My smart meter tells me - I pull at absolute max 10KW at any one time (and that rarely and briefly). I pull 8.5KWh / day, on average, over the last 4 years. My house is entirely electric so that's everything - that's heating, lighting, my computers, cooking, ap