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The new Stanford prototype achieves 5.1 percent power conversion efficiency, but the authors project they could practically reach 27 percent efficiency upon opt

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.
  - 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.
  - 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?
      - namibj 5y ago
        They are not too fragile; they can coat them onto the solar cell's surface.
      - 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.
- 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.

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.
- 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.
- 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?
    - namibj 5y ago
      They are not too fragile; they can coat them onto the solar cell's surface.
    - 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.
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.