15 ms·

Breaking max efficiency of solar cells by activating 2 electrons with 1 photon

543 points by dirtyaura 7y ago

eloff 7y ago
This is incredible. I mean it's a long way to seeing this in affordable silicon solar cells, but still amazing to me that the materials engineering can accomplish things like this. It leads to roughly a twenty percent boost in theoretical max efficiency. If that can be translated to a twenty percent actual improvement, that's huge.
- toomuchtodo 7y ago
  We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. We're rapidly approaching the point where the solar is "almost free" and you're just going to pay for the battery storage (until that cost is rapidly driven down as well). [1] https://www.utilitydive.com/news/los-angeles-solicits-record-solar-storage-deal-at-199713-cents-kwh/558018/ https://www.utilitydive.com/news/los-angeles-solicits-record... (Los Angeles solicits record solar + storage deal at 1.997/1.3-cents kWh)
  - aplummer 7y ago
    I think it would improve the density though creating new applications in or on constrained surfaces (for example, more useful on an expensive car).
  - HereBeBeasties 7y ago
    There's nothing wrong with solar per-se, but it's just not sufficiently power dense if you're talking national scale power usage. https://www.finder.com/uk/solar-power-potential https://www.finder.com/uk/solar-power-potential seems to think that countries like the UK would need more than 10% of their area covering with solar panels to cover their energy needs. I think you'd need to be talking about an order of magnitude improvement in efficiency to really start making it look really feasible as a significant way to change our fossil fuel usage, no?
    - godelski 7y ago
      We also need batteries. But that's why solar is only part of the solution. No single source will solve all the problems in all the areas. I'm a big proponent of nuclear but it's only part. Solar is also what I want to see. But more than the other two I want batteries.
      - plufz 7y ago
        From what I heard from people in the solar business battery is generally not a good idea. Better to invest in a good grid where we can transfer electricity from one place to another (there’s always windy somewhere). And have some sort of backup power plants on the lowest days (like natural gas, biofuel, etc, not co2 free but they wouldn’t be used very often from what I understand). Or alternative “batteries” like pumping up a lot of water in some dam.
        Gibbon1 7y ago
        I like to point out the efficiency gains and load shifting will also reduce off peek demand somewhat. Industrial users will chase lowest cost if possible. If electricity costs 3X at 1am the price at 11am, no ones going to be running an electric furnace at 1am. Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. So it's slightly pointless argue as some do that lack of current solutions is a reason not to move forward with renewables. Worst comes to worst we already have peaking plants that could substitute for baseload power.
        deleted 7y ago
        [deleted]
        godelski 7y ago
        I think there's miscommunication. > lack of current solutions is a reason not to move forward with renewables No one is saying we shouldn't move forward with renewables. Well maybe a certain canine news network, but not anyone here. > Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. What people are saying is there isn't good enough technology yet. So that means that we need to continue funding research. Not being solved means that just building won't be the solution. That we need to spend some serious money researching. That's what people mean by "battery tech isn't there yet". It isn't a defeatist attitude, it is a "continuing and doubling down on research is an important part of the equation" type of attitude. This is typically because that kind of research isn't done by the private sector, but rather government. DOE does a lot of this funding, and even funds a lot of the research being done in the private sector. So being vocal about this means we care and hopefully those in control of allocating that money (probably not by Rick Perry) will spend more on fixing that part of the equation while the private sector does the building out part.
  - hyperpallium 7y ago
    Utility scale cost has been dropping exponentially, but small panels (e.g. 7W phone chargers) haven't. I wonder if the efficiencies will eventually trickle down, or whether the form-factor, other components, retail sales channel and small market for solar phone chargers will prevent this.
    - gtirloni 7y ago
      Way riskier market (consumer goods). It will eventually trickle down though, once it's really mature and countless factories in China have access to it.
    - kragen 7y ago
      I don't build 7W phone chargers, so I could be wrong, but I think there are a couple of factors: · 7Wp of solar panels at this point would cost about US$1.50 if we were talking about the low-cost power modules used in utility-scale deployments. This is, I think, less than the (retail) cost of the case, sales transaction, or power electronics. · Low-cost power modules are less efficient than higher-cost modules, which means you'd need a larger surface area to get 7 watts. Which chargers are you looking at? Searching on Amazon I find a lot of USB battery packs with built-in solar panels, which I can't help but think are basically fake, since a 16%-efficient panel that size would provide less than a watt. (I've probably been influenced by watching a lot of bigclivedotcom videos where he dismantles phony consumer electronics, including USB battery packs that have a tiny fraction of their claimed capacity.)
      - taneq 7y ago
        · Anything is more expensive when you buy one of it than when you buy 10,000,000 of it.
        sigmaprimus 7y ago
        Not always, especially when working with electronics. Many manufacturers offer development parts at one price, then when you try to scale up production you find the price can be double or triple the original cost. Sometimes the smaller fabricating shops are willing to take slimmer margins as they dont have the bloat of managment, regulatory issues and worker costs such as medical and collective barganing agreements.
  - kragen 7y ago
    Thanks for this great link! I posted a somewhat lengthy analysis of the photovoltaic cost structure, and how it relates to the cost structure of more traditional kinds of power stations, yesterday in https://news.ycombinator.com/item?id=20365309 https://news.ycombinator.com/item?id=20365309. Is the power producer in this case receiving subsidies not included in this price, or is 1.997¢ the unsubsidized price?
  - AnthonyMouse 7y ago
    > We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. That price is under optimal conditions. They built in the desert where there are clear skies, lots of sunlight and cheaper land. Plus whatever kind of tax incentives or other subsidies they get in California that conceal part of the cost and may not be available everywhere. The real question is how far can the price continue to fall before it hits a floor. And what happens to the other generation methods as a result of the competition. If people build a bunch of solar farms and storage and replace natural gas plants with them, then there is less demand for natural gas, so the price falls and the remaining natural gas plants stay competitive due to the reduced fuel cost. The "solar takes over everything" narrative is possible, but there is no guarantee of it, and it's probably best not to take it as a hard assumption and make no contingencies for if it doesn't actually work out that way.
    - addicted 7y ago
      Any subsidies solar receives is a tiny fraction of what oil, gas and coal still receive today, without even factoring in all.the subsidies they've received over many years, or the ton of money spent on geopolitics in order to secure fossil fuel supply lines. Or the subsidies and damage they cause when they leak all over the place destroying entire eco systems. And yeah, the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change.
      - waingake 7y ago
        > the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change. This this this
      - cyphar 7y ago
        And the massive "subsidies" given by governments by not prosecuting any criminal or civil charges over the fact that gas and oil companies knew about climate change in the 60s and tried to cover it up.
  - BurningFrog 7y ago
    You'll also have to pay for the real estate.
- Retric 7y ago
  It’s also somewhat misleading we already have solar cells over this theoretical limit. They operate by having multiple layers that operate on different frequencies. So, this really more an alternative manufacturing approach.
  - DennisP 7y ago
    But would this technique also work for multi-layer cells?
    - tedivm 7y ago
      Yeah, in this case it appears that they're focused on the single layers simply because it's easier to build one thing than multiple things. This one was focused on the blue/green portion of the spectrum.
      - deleted 7y ago
        [deleted]
  - atonalfreerider 7y ago
    I disagree that the title is misleading. To anyone familiar with solar cell technology, theoretical limits are discussed in relation to the material in question. Multi-junction cells are not something that are commonly discussed outside of those with expertise, so confusing a theoretical limit with efficiency gains through band gap augmentations is not likely. This is analogous to an article about a chemist discovering a way to get more chemical efficiency out of gasoline and someone saying that we can already do that with a richer air-fuel mix using a turbocharger. The two are not comparable.
    - hn_throwaway_99 7y ago
      Whether or not it is "misleading", I'd say, at least to a layman like myself, it was certainly confusing. Why? Because just yesterday there was an article on the front page touting how Toyota was testing putting improved solar panels on the roofs of their vehicles, and that article quoted an efficiency of 34%, well above the "max theoretical limit" given in the present article: https://news.ycombinator.com/item?id=20364348 https://news.ycombinator.com/item?id=20364348. So I guess my question is how would the proposed manufacturing process in this article be an improvement? Cheaper manufacturing costs? Even higher efficiency if you had "multi-junction cells" made using the processed discussed?
- selimthegrim 7y ago
  The origin of the phenomenon lies in the molecular crystalline layer, the hafnium layer they are talking about keeps the excitons separated and intact.
  - selimthegrim 7y ago
    As well as passivates the Si
Sniffnoy 7y ago
So is two the most possible? Is it possible to activate three electrons with a single photon?
- sp332 7y ago
  Yeah but you'd have to start with very energetic photons. The article says that you mint get two elections when a green or blue photon hits, so to get three even theoretically you'd need to use ultraviolet optics photons. And there just aren't enough of those in sunlight you make a noticeable difference in efficiency.
  - perlgeek 7y ago
    Let me try to do the math here, please correct me if I'm wrong. The band gap of Si in solar cells is about 1.1 ev. To excite three electrons, a photon thus needs 3.3ev, or about 370nm. The visible spectrum starts around 380nm or 390nm, depending on which source you believe. So the triple photon frequency would be very near UV. According to this spectrum [0], there's a sharp drop in solar power around the 370nm. It seems that with the 1.1ev band gap, exciting three electrons doesn't seem to be worth it. But, if you could reduce it just a bit (by doping, most likely), it might be worth considering. Of course, reducing the band gap would likely lead to much worse performance overall, so one would need a multi layer approach, which sounds pretty complicated. And then you need to pray that your glass cover doesn't absorb the UV light, which seems to be a pretty close call[1]. [0]: https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spe... [1]: https://en.wikipedia.org/wiki/Soda%E2%80%93lime_glass#/media/File:Soda-lime_glass,_typical_transmission_spectrum_(2_mm_thickness).svg https://en.wikipedia.org/wiki/Soda%E2%80%93lime_glass#/media...
    - pixl97 7y ago
      All that said, in space based operations your UV isnt going to be filtered and may allow you to generate more power.
- aurizon 7y ago
mycall 7y ago
Interesting how "through a process called singlet exciton fission" and other article "General Formula for Bi-Aspheric Singlet Lens Design Free of Spherical Aberration" [1] both deal with Singlets. Odd coincidence of the day. [1] https://www.osapublishing.org/ao/abstract.cfm?uri=ao-57-31-9341 https://www.osapublishing.org/ao/abstract.cfm?uri=ao-57-31-9...
- albutr 7y ago
  FYI they are totally different "singlets", a singlet exciton refers to the spin state of the particle (as opposed to a triplet exciton, which has a different total spin). A singlet lens is just a lens with a single simple component.
geoalchimista 7y ago
"2 electrons with 1 photon" --- that is how photosynthesis works in nature. Great thinking!
- snaky 7y ago
  Photosynthesis is less efficient than solar panels. According to the Wikipedia page on photosynthetic efficiency, typical plants have a radiant energy to chemical energy conversion efficiency between 0.1% and 2%.
  - geoalchimista 7y ago
    It's true but photosynthesis has two stages. The light reaction stage is quite efficient. Chlorophyll a is slightly more efficient than commercial solar panels. The dark reaction stage, which assimilates CO2 to produce carbohydrates, is the limiting step that drives the efficiency down.
    - anticensor 7y ago
      Non-light sensitive parts of photosynthesis has to be inefficient because otherwise aerobic respiration would be inefficient.
  - timbit42 7y ago
    What about bamboo?
    - kragen 7y ago
      Yes, bamboo too. Sorry.
      - snovv_crash 7y ago
        The outlier is sugar cane, with efficiency around 8%
  - Obi_Juan_Kenobi 7y ago
dharma1 7y ago
This is great - but isn’t hafnium pretty rare?
- igravious 7y ago
  Yes, but at least it's twice as abundant as forthnium.
  - benj111 7y ago
    You mean quartnernium.
    - igravious 7y ago
      Yanks say "one fourth", Brits say "one quarter": https://forum.wordreference.com/threads/a-fourth-a-quarter.3065667/ https://forum.wordreference.com/threads/a-fourth-a-quarter.3... I knew there was a high likelihood that I would be downvoted to oblivion for making a terrible Dad joke, but it was worth it. I feel that a few years back I could maybe have cracked that joke without my karma being bludgeoned.
      - benj111 7y ago
        "Yanks say "one fourth", Brits say "one quarter"" Didn't know that, thanks, you'd have thought I'd have worked it out by now, but then it took me far too long to work out what a 'fawcet' was. Re karma. You will live a much happier life not worrying about some random on the internet downvoting you.
- marcosdumay 7y ago
  I may be common enough for a 3 atoms wide layer. Is there any large scale tentative of refining it?
- maxerickson 7y ago
  It's about 1000 times more abundant in Earth's crust than gold.
selimthegrim 7y ago
I'm glad to see Baldo has moved on from useless experiments on hexacene. Sincere congratulations to him and his group.
m3kw9 7y ago
I mean it all means bunk till a mass produced product is on the shelves. A lot of these “breakthrus” fail to note edge cases like scalability, durability
- rossdavidh 7y ago
  While true, it's worth noting that it's happened. It's rather like when there's a theoretical breakthrough that might help to cure a type of cancer. Will it result in an actual medical breakthrough that helps people? Usually not. But, occasionally yes, and that's huge, so it's still worth noting. If you don't get enough shots on goal, you never score.
- lm28469 7y ago
  When we first discovered uranium we made drinks and lipsticks out of it. Now we use it to get insane amount of energy and bombs. Sometimes there are decades between the "breakthrough" and the use of it. Most of the time the finale usage has not much to do with the initial breakthrough. https://www.philips.com/c-w/malegrooming/philips-space/space/10-space-innovations-that-are-closer-than-you-think.html https://www.philips.com/c-w/malegrooming/philips-space/space...
georgeburdell 7y ago
Pardon my ignorance but don't avalanche photodiodes, scintillators, phosphors, etc. excite many electrons per 1 photon? Why is 2 electrons for 1 photon noteworthy?
- ambicapter 7y ago
  I assume those are powered.
selimthegrim 7y ago
https://cen.acs.org/energy/solar-power/Supercharging-silicon-solar-cell/97/web/2019/07 https://cen.acs.org/energy/solar-power/Supercharging-silicon... has some good takes from people in the field

543 points by dirtyaura 7y ago

This is incredible. I mean it's a long way to seeing this in affordable silicon solar cells, but still amazing to me that the materials engineering can accomplish things like this. It leads to roughly a twenty percent boost in theoretical max efficiency. If that can be translated to a twenty percent actual improvement, that's huge.

toomuchtodo 7y ago
We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. We're rapidly approaching the point where the solar is "almost free" and you're just going to pay for the battery storage (until that cost is rapidly driven down as well). [1] https://www.utilitydive.com/news/los-angeles-solicits-record-solar-storage-deal-at-199713-cents-kwh/558018/ https://www.utilitydive.com/news/los-angeles-solicits-record... (Los Angeles solicits record solar + storage deal at 1.997/1.3-cents kWh)
- aplummer 7y ago
  I think it would improve the density though creating new applications in or on constrained surfaces (for example, more useful on an expensive car).
- HereBeBeasties 7y ago
  There's nothing wrong with solar per-se, but it's just not sufficiently power dense if you're talking national scale power usage. https://www.finder.com/uk/solar-power-potential https://www.finder.com/uk/solar-power-potential seems to think that countries like the UK would need more than 10% of their area covering with solar panels to cover their energy needs. I think you'd need to be talking about an order of magnitude improvement in efficiency to really start making it look really feasible as a significant way to change our fossil fuel usage, no?
  - godelski 7y ago
    We also need batteries. But that's why solar is only part of the solution. No single source will solve all the problems in all the areas. I'm a big proponent of nuclear but it's only part. Solar is also what I want to see. But more than the other two I want batteries.
    - plufz 7y ago
      From what I heard from people in the solar business battery is generally not a good idea. Better to invest in a good grid where we can transfer electricity from one place to another (there’s always windy somewhere). And have some sort of backup power plants on the lowest days (like natural gas, biofuel, etc, not co2 free but they wouldn’t be used very often from what I understand). Or alternative “batteries” like pumping up a lot of water in some dam.
      - Gibbon1 7y ago
        I like to point out the efficiency gains and load shifting will also reduce off peek demand somewhat. Industrial users will chase lowest cost if possible. If electricity costs 3X at 1am the price at 11am, no ones going to be running an electric furnace at 1am. Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. So it's slightly pointless argue as some do that lack of current solutions is a reason not to move forward with renewables. Worst comes to worst we already have peaking plants that could substitute for baseload power.
        deleted 7y ago
        [deleted]
        godelski 7y ago
        I think there's miscommunication. > lack of current solutions is a reason not to move forward with renewables No one is saying we shouldn't move forward with renewables. Well maybe a certain canine news network, but not anyone here. > Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. What people are saying is there isn't good enough technology yet. So that means that we need to continue funding research. Not being solved means that just building won't be the solution. That we need to spend some serious money researching. That's what people mean by "battery tech isn't there yet". It isn't a defeatist attitude, it is a "continuing and doubling down on research is an important part of the equation" type of attitude. This is typically because that kind of research isn't done by the private sector, but rather government. DOE does a lot of this funding, and even funds a lot of the research being done in the private sector. So being vocal about this means we care and hopefully those in control of allocating that money (probably not by Rick Perry) will spend more on fixing that part of the equation while the private sector does the building out part.
- hyperpallium 7y ago
  Utility scale cost has been dropping exponentially, but small panels (e.g. 7W phone chargers) haven't. I wonder if the efficiencies will eventually trickle down, or whether the form-factor, other components, retail sales channel and small market for solar phone chargers will prevent this.
  - gtirloni 7y ago
    Way riskier market (consumer goods). It will eventually trickle down though, once it's really mature and countless factories in China have access to it.
  - kragen 7y ago
    I don't build 7W phone chargers, so I could be wrong, but I think there are a couple of factors: · 7Wp of solar panels at this point would cost about US$1.50 if we were talking about the low-cost power modules used in utility-scale deployments. This is, I think, less than the (retail) cost of the case, sales transaction, or power electronics. · Low-cost power modules are less efficient than higher-cost modules, which means you'd need a larger surface area to get 7 watts. Which chargers are you looking at? Searching on Amazon I find a lot of USB battery packs with built-in solar panels, which I can't help but think are basically fake, since a 16%-efficient panel that size would provide less than a watt. (I've probably been influenced by watching a lot of bigclivedotcom videos where he dismantles phony consumer electronics, including USB battery packs that have a tiny fraction of their claimed capacity.)
    - taneq 7y ago
      · Anything is more expensive when you buy one of it than when you buy 10,000,000 of it.
      - sigmaprimus 7y ago
        Not always, especially when working with electronics. Many manufacturers offer development parts at one price, then when you try to scale up production you find the price can be double or triple the original cost. Sometimes the smaller fabricating shops are willing to take slimmer margins as they dont have the bloat of managment, regulatory issues and worker costs such as medical and collective barganing agreements.
- kragen 7y ago
  Thanks for this great link! I posted a somewhat lengthy analysis of the photovoltaic cost structure, and how it relates to the cost structure of more traditional kinds of power stations, yesterday in https://news.ycombinator.com/item?id=20365309 https://news.ycombinator.com/item?id=20365309. Is the power producer in this case receiving subsidies not included in this price, or is 1.997¢ the unsubsidized price?
- AnthonyMouse 7y ago
  > We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. That price is under optimal conditions. They built in the desert where there are clear skies, lots of sunlight and cheaper land. Plus whatever kind of tax incentives or other subsidies they get in California that conceal part of the cost and may not be available everywhere. The real question is how far can the price continue to fall before it hits a floor. And what happens to the other generation methods as a result of the competition. If people build a bunch of solar farms and storage and replace natural gas plants with them, then there is less demand for natural gas, so the price falls and the remaining natural gas plants stay competitive due to the reduced fuel cost. The "solar takes over everything" narrative is possible, but there is no guarantee of it, and it's probably best not to take it as a hard assumption and make no contingencies for if it doesn't actually work out that way.
  - addicted 7y ago
    Any subsidies solar receives is a tiny fraction of what oil, gas and coal still receive today, without even factoring in all.the subsidies they've received over many years, or the ton of money spent on geopolitics in order to secure fossil fuel supply lines. Or the subsidies and damage they cause when they leak all over the place destroying entire eco systems. And yeah, the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change.
    - waingake 7y ago
      > the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change. This this this
    - cyphar 7y ago
      And the massive "subsidies" given by governments by not prosecuting any criminal or civil charges over the fact that gas and oil companies knew about climate change in the 60s and tried to cover it up.
- BurningFrog 7y ago
  You'll also have to pay for the real estate.
Retric 7y ago
It’s also somewhat misleading we already have solar cells over this theoretical limit. They operate by having multiple layers that operate on different frequencies. So, this really more an alternative manufacturing approach.
- DennisP 7y ago
  But would this technique also work for multi-layer cells?
  - tedivm 7y ago
    Yeah, in this case it appears that they're focused on the single layers simply because it's easier to build one thing than multiple things. This one was focused on the blue/green portion of the spectrum.
    - deleted 7y ago
      [deleted]
- atonalfreerider 7y ago
  I disagree that the title is misleading. To anyone familiar with solar cell technology, theoretical limits are discussed in relation to the material in question. Multi-junction cells are not something that are commonly discussed outside of those with expertise, so confusing a theoretical limit with efficiency gains through band gap augmentations is not likely. This is analogous to an article about a chemist discovering a way to get more chemical efficiency out of gasoline and someone saying that we can already do that with a richer air-fuel mix using a turbocharger. The two are not comparable.
  - hn_throwaway_99 7y ago
    Whether or not it is "misleading", I'd say, at least to a layman like myself, it was certainly confusing. Why? Because just yesterday there was an article on the front page touting how Toyota was testing putting improved solar panels on the roofs of their vehicles, and that article quoted an efficiency of 34%, well above the "max theoretical limit" given in the present article: https://news.ycombinator.com/item?id=20364348 https://news.ycombinator.com/item?id=20364348. So I guess my question is how would the proposed manufacturing process in this article be an improvement? Cheaper manufacturing costs? Even higher efficiency if you had "multi-junction cells" made using the processed discussed?
selimthegrim 7y ago
The origin of the phenomenon lies in the molecular crystalline layer, the hafnium layer they are talking about keeps the excitons separated and intact.
- selimthegrim 7y ago
  As well as passivates the Si

Sniffnoy 7y ago

So is two the most possible? Is it possible to activate three electrons with a single photon?

sp332 7y ago
Yeah but you'd have to start with very energetic photons. The article says that you mint get two elections when a green or blue photon hits, so to get three even theoretically you'd need to use ultraviolet optics photons. And there just aren't enough of those in sunlight you make a noticeable difference in efficiency.
- perlgeek 7y ago
  Let me try to do the math here, please correct me if I'm wrong. The band gap of Si in solar cells is about 1.1 ev. To excite three electrons, a photon thus needs 3.3ev, or about 370nm. The visible spectrum starts around 380nm or 390nm, depending on which source you believe. So the triple photon frequency would be very near UV. According to this spectrum [0], there's a sharp drop in solar power around the 370nm. It seems that with the 1.1ev band gap, exciting three electrons doesn't seem to be worth it. But, if you could reduce it just a bit (by doping, most likely), it might be worth considering. Of course, reducing the band gap would likely lead to much worse performance overall, so one would need a multi layer approach, which sounds pretty complicated. And then you need to pray that your glass cover doesn't absorb the UV light, which seems to be a pretty close call[1]. [0]: https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spe... [1]: https://en.wikipedia.org/wiki/Soda%E2%80%93lime_glass#/media/File:Soda-lime_glass,_typical_transmission_spectrum_(2_mm_thickness).svg https://en.wikipedia.org/wiki/Soda%E2%80%93lime_glass#/media...
  - pixl97 7y ago
    All that said, in space based operations your UV isnt going to be filtered and may allow you to generate more power.
aurizon 7y ago

mycall 7y ago

Interesting how "through a process called singlet exciton fission" and other article "General Formula for Bi-Aspheric Singlet Lens Design Free of Spherical Aberration" [1] both deal with Singlets. Odd coincidence of the day. [1] https://www.osapublishing.org/ao/abstract.cfm?uri=ao-57-31-9341 https://www.osapublishing.org/ao/abstract.cfm?uri=ao-57-31-9...

albutr 7y ago
FYI they are totally different "singlets", a singlet exciton refers to the spin state of the particle (as opposed to a triplet exciton, which has a different total spin). A singlet lens is just a lens with a single simple component.

geoalchimista 7y ago

"2 electrons with 1 photon" --- that is how photosynthesis works in nature. Great thinking!

snaky 7y ago
Photosynthesis is less efficient than solar panels. According to the Wikipedia page on photosynthetic efficiency, typical plants have a radiant energy to chemical energy conversion efficiency between 0.1% and 2%.
- geoalchimista 7y ago
  It's true but photosynthesis has two stages. The light reaction stage is quite efficient. Chlorophyll a is slightly more efficient than commercial solar panels. The dark reaction stage, which assimilates CO2 to produce carbohydrates, is the limiting step that drives the efficiency down.
  - anticensor 7y ago
    Non-light sensitive parts of photosynthesis has to be inefficient because otherwise aerobic respiration would be inefficient.
- timbit42 7y ago
  What about bamboo?
  - kragen 7y ago
    Yes, bamboo too. Sorry.
    - snovv_crash 7y ago
      The outlier is sugar cane, with efficiency around 8%
- Obi_Juan_Kenobi 7y ago

dharma1 7y ago

This is great - but isn’t hafnium pretty rare?

igravious 7y ago
Yes, but at least it's twice as abundant as forthnium.
- benj111 7y ago
  You mean quartnernium.
  - igravious 7y ago
    Yanks say "one fourth", Brits say "one quarter": https://forum.wordreference.com/threads/a-fourth-a-quarter.3065667/ https://forum.wordreference.com/threads/a-fourth-a-quarter.3... I knew there was a high likelihood that I would be downvoted to oblivion for making a terrible Dad joke, but it was worth it. I feel that a few years back I could maybe have cracked that joke without my karma being bludgeoned.
    - benj111 7y ago
      "Yanks say "one fourth", Brits say "one quarter"" Didn't know that, thanks, you'd have thought I'd have worked it out by now, but then it took me far too long to work out what a 'fawcet' was. Re karma. You will live a much happier life not worrying about some random on the internet downvoting you.
marcosdumay 7y ago
I may be common enough for a 3 atoms wide layer. Is there any large scale tentative of refining it?
maxerickson 7y ago
It's about 1000 times more abundant in Earth's crust than gold.

selimthegrim 7y ago

I'm glad to see Baldo has moved on from useless experiments on hexacene. Sincere congratulations to him and his group.

m3kw9 7y ago

I mean it all means bunk till a mass produced product is on the shelves. A lot of these “breakthrus” fail to note edge cases like scalability, durability

rossdavidh 7y ago
While true, it's worth noting that it's happened. It's rather like when there's a theoretical breakthrough that might help to cure a type of cancer. Will it result in an actual medical breakthrough that helps people? Usually not. But, occasionally yes, and that's huge, so it's still worth noting. If you don't get enough shots on goal, you never score.
lm28469 7y ago
When we first discovered uranium we made drinks and lipsticks out of it. Now we use it to get insane amount of energy and bombs. Sometimes there are decades between the "breakthrough" and the use of it. Most of the time the finale usage has not much to do with the initial breakthrough. https://www.philips.com/c-w/malegrooming/philips-space/space/10-space-innovations-that-are-closer-than-you-think.html https://www.philips.com/c-w/malegrooming/philips-space/space...

georgeburdell 7y ago

Pardon my ignorance but don't avalanche photodiodes, scintillators, phosphors, etc. excite many electrons per 1 photon? Why is 2 electrons for 1 photon noteworthy?

ambicapter 7y ago
I assume those are powered.

selimthegrim 7y ago

https://cen.acs.org/energy/solar-power/Supercharging-silicon-solar-cell/97/web/2019/07 https://cen.acs.org/energy/solar-power/Supercharging-silicon... has some good takes from people in the field