5 ms·

New materials could deliver ultrathin solar panels

57 points by stareatgoats 5y ago

SQL2219 5y ago
The new Stanford prototype achieves 5.1 percent power conversion efficiency, but the authors project they could practically reach 27 percent efficiency upon optical and electrical optimizations. That figure would be on par with the best solar panels on the market today, silicon included.
- jacquesm 5y ago
  I'll believe it when I see it. Solar panels and batteries are both subjects that have generated far more in terms of improvements on paper than they delivered in real life.
  - dogma1138 5y ago
    To add to that you simply can’t escape physics… A 200W solar panel with 20% conversion efficiency needs a 1000W of solar radiation hitting it to produce that much, most of it would be converted into heat, that’s roughly the average for an area just under 1 sq/m in size. Thermals are a big problem for solar panels and I’m not sure how that would work with thinner panels. I also don’t see how you’ll power a drone with solar panels regarding how much they weight the surface area seems not to be sufficient even if the panels would be 80-90% efficient.
    - jacquesm 5y ago
      On the plus side, every little bit that can be exported as electrons does not need to be shed as IR. The problem is that quite a bit of that 1000W incident is not in a part of the spectrum that lends itself readily to conversion to electricity.
      - addaon 5y ago
        Couldn't one build a dielectric mirror onto the surface of the panel to selectively reflect those frequencies that aren't converted well, to avoid the thermal load of absorbing them? Is the issue that dielectric mirrors are too fragile?
        jacquesm 5y ago
        No, the problem is that your dielectric mirror would have to be a perfect reflector for one set of wavelengths and a perfect passthrough for the remainder. In practice though it will always be gradients so you'll end up reflecting some of what you want and passing some of what you don't want.
        namibj 5y ago
        They are not too fragile; they can coat them onto the solar cell's surface.
    - labawi 5y ago
      Panel thickness is not a positive factor for cooling, it's only good for structural support. Unless your panels are tiny, all the heat escapes through the front/back surfaces, thinner being better, though surface treatment and airflow is a bigger factor. If they meant winged drones - those already exist.
  - sdenton4 5y ago
    You haven't been paying attention, I suppose. The cost per watt of solar panels continues to drop exponentially, as optimizations continue and production continues to scale up. Breakthrough research announcements like this happen often, and only a handful of such announcements will ever make it to production. But improvements certainly /are/ making it into production, and lowering LCOE steadily. Here's an example graph, with both solar and battery costs: https://greentechlead.com/renewable-energy/cost-for-onshore-wind-solar-and-battery-storage-dipped-bnef-35985 https://greentechlead.com/renewable-energy/cost-for-onshore-... And compared to fossil fuels: https://en.wikipedia.org/wiki/Levelized_cost_of_energy#/media/File:20201019_Levelized_Cost_of_Energy_(LCOE,_Lazard)_-_renewable_energy.svg https://en.wikipedia.org/wiki/Levelized_cost_of_energy#/medi... (LOTS of people think about renewable prices as they were ten years ago instead of where they are now or where they may be in five years. This means lots of people simply have wrong priors about the relative cost of different energy sources. This is expected: People don't intuitively adapt to exponential change.)
    - fooblaster 5y ago
      The graphs you mentioned are about cost per watt, an important metric, but not panle conversion efficiency.
    - jacquesm 5y ago
      I've been paying excellent attention, the panel efficiency for the various crystal lattices and layering combinations has hardly moved in the last decade. A little bit here, a little bit there. Sure the price has come down, but that wasn't what this was about. Also, I think the tone of your comment could be a lot better than it is.
      - sdenton4 5y ago
        Here's some progression of panel efficiency over time: https://news.energysage.com/solar-panel-efficiency-cost-over-time/ https://news.energysage.com/solar-panel-efficiency-cost-over... I would suggest it's a matter of "nothing changes in a year but everything changes in a decade." Partial apologies for the tone; I'm personally kinda sick of Internet comments crapping on people's work by default.
labawi 5y ago
Thin/flexible cells are often called "eco", because "less material", but then I find the composition and they are made of Arsenic, Cadmium or similar toxic non-degradable materials that will end up in the environment. This one seems actually seems very ecological, or at least not toxic: > tungsten diselenide and contacts of gold spanned by a layer of conducting graphene that is just a single atom thick They don't mention Cadmium Sulfide surface layer as seems standard in CIGS. Hope they don't feel the need to add it in the efficiency optimization process. EDIT: Doing some calculation on CIGS with 700Å (70nm) CdS layer [1], 1m² of solar panel would have about 1m²·70nm·5g/cm³ = 1m²·70e-9m·5e6g/m³ ~ 0.4g of CdS. [1] https://www.nrel.gov/pv/copper-indium-gallium-diselenide-solar-cells.html https://www.nrel.gov/pv/copper-indium-gallium-diselenide-sol...
- truculent 5y ago
  There was an interesting post shared here recently on low-tech solar panels, which might be able to trade off efficiency for recyclability: https://solar.lowtechmagazine.com/2021/10/how-to-build-a-low-tech-solar-panel.html https://solar.lowtechmagazine.com/2021/10/how-to-build-a-low...
  - labawi 5y ago
    > The plug was an alloy of zinc and antimony – which we now know is a semiconductor. It was alternately capped by German silver (a nickel, copper, and zinc alloy) and copper on opposite ends. While the design may be possible to make and repair in artisanal manner, it uses a lot of antimony and any repairs would likely shed more Sb than there is Cd in an entire CIGS panel (though In and Ga may be a concern). If the design was resource-optimized, it would still have a potent monk-killer (Sb) and then it wouldn't be worth it to recycle all of the panels.
jacquesm 5y ago
Another entry in this already very long list: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=could%20solar%20panels&sort=byPopularity&type=story https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
- tibyat 5y ago
mrfusion 5y ago
The best thing about being very thin is that they could be folded up into smaller spaces. You could unfold 100m of panels from the back of your EV when you park. Or carry enough in your backpack to power your lappy.
- dntrkv 5y ago
  I get your point, but you can already carry enough panels in your backup to power your laptop. I have a 100W folding panel that folds down to about 10x8x2.5” I bought it for $200 about a year back, you can pick it up today for $140. Crazy how fast prices are dropping.
  - cced 5y ago
    Link to model? Any recommendations?
    - dntrkv 5y ago
      Look up the Topsolar SolarFairy 100W it’s a Chinese brand you can order on Amazon. I also have a Dokio 220W folding panel that’s my main one for camping, but it’s way bigger. Though it’s really thin and easy to find a place to store without taking up much space, it’s also easier to keep directed at the sun.
bluGill 5y ago
Thin isn't as useful as it sounds. For a few application (drones) light weight is important, and thin probably does mean light weight. However for most solar application a bit of extra thickness is just something you design into your mounting system, and since thicker is stronger (think hail and other weather phenomenons) you typically design panels far thicker than needed to support the cell anyway.
- closetnerd 5y ago
  Transportation at the least. Got a place in the mountains - moving a few panels was a insanely costly and annoying.
LightG 5y ago
This is good, but shouldn't the priority maximising power output from X area of solar panel? I would have thought the industry needs customers to get excited about covering their electricity bills (especially now), let alone just getting to a point where residential customers can enjoy a day of full power without dipping into the grid. (It's likely I don't know what I'm talking about with the above, but I know what I feel as a potential solar power customer. I imagine this is addressing a different problem that others are interested in, but I wish the industry would solve the most pressing problem).

57 points by stareatgoats 5y ago

The new Stanford prototype achieves 5.1 percent power conversion efficiency, but the authors project they could practically reach 27 percent efficiency upon optical and electrical optimizations. That figure would be on par with the best solar panels on the market today, silicon included.

jacquesm 5y ago
I'll believe it when I see it. Solar panels and batteries are both subjects that have generated far more in terms of improvements on paper than they delivered in real life.
- dogma1138 5y ago
  To add to that you simply can’t escape physics… A 200W solar panel with 20% conversion efficiency needs a 1000W of solar radiation hitting it to produce that much, most of it would be converted into heat, that’s roughly the average for an area just under 1 sq/m in size. Thermals are a big problem for solar panels and I’m not sure how that would work with thinner panels. I also don’t see how you’ll power a drone with solar panels regarding how much they weight the surface area seems not to be sufficient even if the panels would be 80-90% efficient.
  - jacquesm 5y ago
    On the plus side, every little bit that can be exported as electrons does not need to be shed as IR. The problem is that quite a bit of that 1000W incident is not in a part of the spectrum that lends itself readily to conversion to electricity.
    - addaon 5y ago
      Couldn't one build a dielectric mirror onto the surface of the panel to selectively reflect those frequencies that aren't converted well, to avoid the thermal load of absorbing them? Is the issue that dielectric mirrors are too fragile?
      - jacquesm 5y ago
        No, the problem is that your dielectric mirror would have to be a perfect reflector for one set of wavelengths and a perfect passthrough for the remainder. In practice though it will always be gradients so you'll end up reflecting some of what you want and passing some of what you don't want.
      - namibj 5y ago
        They are not too fragile; they can coat them onto the solar cell's surface.
  - labawi 5y ago
    Panel thickness is not a positive factor for cooling, it's only good for structural support. Unless your panels are tiny, all the heat escapes through the front/back surfaces, thinner being better, though surface treatment and airflow is a bigger factor. If they meant winged drones - those already exist.
- sdenton4 5y ago
  You haven't been paying attention, I suppose. The cost per watt of solar panels continues to drop exponentially, as optimizations continue and production continues to scale up. Breakthrough research announcements like this happen often, and only a handful of such announcements will ever make it to production. But improvements certainly /are/ making it into production, and lowering LCOE steadily. Here's an example graph, with both solar and battery costs: https://greentechlead.com/renewable-energy/cost-for-onshore-wind-solar-and-battery-storage-dipped-bnef-35985 https://greentechlead.com/renewable-energy/cost-for-onshore-... And compared to fossil fuels: https://en.wikipedia.org/wiki/Levelized_cost_of_energy#/media/File:20201019_Levelized_Cost_of_Energy_(LCOE,_Lazard)_-_renewable_energy.svg https://en.wikipedia.org/wiki/Levelized_cost_of_energy#/medi... (LOTS of people think about renewable prices as they were ten years ago instead of where they are now or where they may be in five years. This means lots of people simply have wrong priors about the relative cost of different energy sources. This is expected: People don't intuitively adapt to exponential change.)
  - fooblaster 5y ago
    The graphs you mentioned are about cost per watt, an important metric, but not panle conversion efficiency.
  - jacquesm 5y ago
    I've been paying excellent attention, the panel efficiency for the various crystal lattices and layering combinations has hardly moved in the last decade. A little bit here, a little bit there. Sure the price has come down, but that wasn't what this was about. Also, I think the tone of your comment could be a lot better than it is.
    - sdenton4 5y ago
      Here's some progression of panel efficiency over time: https://news.energysage.com/solar-panel-efficiency-cost-over-time/ https://news.energysage.com/solar-panel-efficiency-cost-over... I would suggest it's a matter of "nothing changes in a year but everything changes in a decade." Partial apologies for the tone; I'm personally kinda sick of Internet comments crapping on people's work by default.

labawi 5y ago

Thin/flexible cells are often called "eco", because "less material", but then I find the composition and they are made of Arsenic, Cadmium or similar toxic non-degradable materials that will end up in the environment. This one seems actually seems very ecological, or at least not toxic: > tungsten diselenide and contacts of gold spanned by a layer of conducting graphene that is just a single atom thick They don't mention Cadmium Sulfide surface layer as seems standard in CIGS. Hope they don't feel the need to add it in the efficiency optimization process. EDIT: Doing some calculation on CIGS with 700Å (70nm) CdS layer [1], 1m² of solar panel would have about 1m²·70nm·5g/cm³ = 1m²·70e-9m·5e6g/m³ ~ 0.4g of CdS. [1] https://www.nrel.gov/pv/copper-indium-gallium-diselenide-solar-cells.html https://www.nrel.gov/pv/copper-indium-gallium-diselenide-sol...

truculent 5y ago
There was an interesting post shared here recently on low-tech solar panels, which might be able to trade off efficiency for recyclability: https://solar.lowtechmagazine.com/2021/10/how-to-build-a-low-tech-solar-panel.html https://solar.lowtechmagazine.com/2021/10/how-to-build-a-low...
- labawi 5y ago
  > The plug was an alloy of zinc and antimony – which we now know is a semiconductor. It was alternately capped by German silver (a nickel, copper, and zinc alloy) and copper on opposite ends. While the design may be possible to make and repair in artisanal manner, it uses a lot of antimony and any repairs would likely shed more Sb than there is Cd in an entire CIGS panel (though In and Ga may be a concern). If the design was resource-optimized, it would still have a potent monk-killer (Sb) and then it wouldn't be worth it to recycle all of the panels.

jacquesm 5y ago

Another entry in this already very long list: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=could%20solar%20panels&sort=byPopularity&type=story https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

tibyat 5y ago

mrfusion 5y ago

The best thing about being very thin is that they could be folded up into smaller spaces. You could unfold 100m of panels from the back of your EV when you park. Or carry enough in your backpack to power your lappy.

dntrkv 5y ago
I get your point, but you can already carry enough panels in your backup to power your laptop. I have a 100W folding panel that folds down to about 10x8x2.5” I bought it for $200 about a year back, you can pick it up today for $140. Crazy how fast prices are dropping.
- cced 5y ago
  Link to model? Any recommendations?
  - dntrkv 5y ago
    Look up the Topsolar SolarFairy 100W it’s a Chinese brand you can order on Amazon. I also have a Dokio 220W folding panel that’s my main one for camping, but it’s way bigger. Though it’s really thin and easy to find a place to store without taking up much space, it’s also easier to keep directed at the sun.

bluGill 5y ago

Thin isn't as useful as it sounds. For a few application (drones) light weight is important, and thin probably does mean light weight. However for most solar application a bit of extra thickness is just something you design into your mounting system, and since thicker is stronger (think hail and other weather phenomenons) you typically design panels far thicker than needed to support the cell anyway.

closetnerd 5y ago
Transportation at the least. Got a place in the mountains - moving a few panels was a insanely costly and annoying.

LightG 5y ago

This is good, but shouldn't the priority maximising power output from X area of solar panel? I would have thought the industry needs customers to get excited about covering their electricity bills (especially now), let alone just getting to a point where residential customers can enjoy a day of full power without dipping into the grid. (It's likely I don't know what I'm talking about with the above, but I know what I feel as a potential solar power customer. I imagine this is addressing a different problem that others are interested in, but I wish the industry would solve the most pressing problem).