You can't reach 25% efficiency with monocrystalline silicon PV even with the entire industrial economy backing you up; those efficiencies require multijunction solar cells. Conveniently homebrewable PV panels, like the ZnO:Mg/Cu2O cells you link below, are closer to 1% efficient. The author reports 525mV and 0.9mA/cm², which works out to 4.7W/m², which would be 0.5% efficient if the illumination is one sun.
They probably are a better approach than the thermoelectric approach, because not only are they more efficient, they use more abundant materials and thinner films of them. But either approach could plausibly defeat the other.
Longi has demonstrated a champion monocrystalline silicon cell at 27.3% efficiency and it has silicon cells over 26% efficiency in mass production. It has demonstrated a champion silicon module at 25.4% efficiency.
Thermoelectric devices are interesting because they can be manufactured using comparatively simple metallurgy. Not because their efficiency is competitive with semiconductor photovoltaics.
Solar panels enabling offgrid power is tagcloud-related to surviving human civilization collapse.
We're entering an era of decreased globalism, where megacorporation scale actually becomes a danger to society due to reduced warehousing/stockpiling and long extended supply lines, and of course offshored manufacturing that goes with that.
Before solar panels become impossible to purchase, they will be difficult to purchase.
Before solar panels become difficult to purchase, they will become more expensive to purchase.
Mass produced solar panels have been getting both cheaper and easier to get. What you describe could happen, but it's far enough off that we have not seen even the first warning signs yet.
Okay, sure, but that's no different than the same identical "warning signs" that people have been flipping out about since the 1960s.
Maybe some individual country will have some collapse, but all of human civilization will not.
I.maintain that if you're worried about any of that, you are still better off stockpiling panels now, than developing ways to make your own much worse ones in your backyard.
DIY photovoltaics can be a fun hobby but for someone worried about an actual collapse they can acquire a lifetime supply of solar panels and batteries for less money and time than setting up a custom fab that's able to operate in a collapse situation.
Is your argument because we have not had a nuclear war yet, we will never have one?
Can you elaborate? I would like to have your confidence ..
And in general setting up a solar panel fab is maybe not the best prepper action, but for the point of distributing critical techologies for a potential reconstruction, I do see the point.
There is individual survival and general progress of the species.
There's exactly one scenario that results in the actual technological collapse of our species, which is all out nuclear war between the US and Russia. Which with the current presidential administration, is possibly less likely than it's ever been; why would Russia nuke its newest ally?
The chances of a nuclear weapon being used somewhere right now tactically I think are quite high. Russia in Ukraine, or Israel in Iran (or someday soon Iran in Israel), or between India and Pakistan. But none of those are sufficient to bring us to a point where home manufacturing of solar panels becomes remotely worthwhile.
I believe it's optimistic to think that that is the only scenario. Consider the problems we had during the pandemic, which was luckily just a minor blip as far as possible global disruptions go.
The problem is, except for the very first ones in Japan, there were never any nuclear weapons being used in a major war exactly for the unknown consequences of the other players.
It is all interconnected. If one nuke is used, then there will be many on the other side applying pressure to also use a nuke. And so on. I assume much more countries secretly have nukes and the frontlines are somewhat blurry. Meaning, at the moment I am also not too worried, but if a nuke is used it will be a very high gamble, that it will be just the only one.
Most countries definitely do not have nukes. There are a handful that could have them in secret, or that maintain the materials to make them immediately if needed. But all of those combined would amount to no more than a few dozen, small, nuclear weapons. There are not a thousand Tsar Bomba size nukes secreted away.
If the US and Russia stood down and the rest of the world let loose all of their nukes, it would be insufficient to cause sufficient damage to the technological integrity of our species such that backyard solar manufacture becomes viable.
I claim it will be hard to limit the use of nuclear weapons.
Just like in the weapons itself, one ignition can trigger a chain reaction in the end forcing russia or US to take part in it as well. If all the people involved are level headed and able to think rational - it likely will prevented also in the future. But if the person in charge is already stressed (and old) and gets lots of pressure - this person, might then feel forced to press a button.
You said "I assume much more countries secretly have nukes".
I claim that beyond the open secret that is Israel, the number of countries controlling a right-now detonatable nuclear weapon who are not on the Wikipedia list of "countries with nukes" is less than 5.
Claiming much more countries secretly have one, is not at all the same as claiming most countries secretly have them. And I agree that it won't be many many, but in this context one previously unknown bomb already might change lots of geopolitical equations and their outcome.
hacker spirit and/or hedge against the end of the industrial age
Personally, I don't have much faith in sustaining a modern industrial lifestyle for billions of people very long term on PV panels or any renewables really (EROEI issues, rare earth minerals etc.). But I'm bullish on electricity in general.
By far the most common PV systems are single-junction monocrystalline silicon. These have had pretty decent ERoEI for many years (9–10 according to https://www.nrel.gov/docs/fy17osti/67901.pdf, but the energy required for PV modules has dropped precipitously since then) and don't use any rare-earth minerals.
Wind turbines have typically had even higher ERoEI (15–20 according to https://davidturver.substack.com/p/eroei-eroi-of-onshore-off...), and, while they do most commonly use rare earths, that's an engineering tradeoff rather than necessary; currently viable alternatives include switched-reluctance-machine generators (which just use conventional electrical steel, like transformers and relays) and other kinds of rare-earth-free generators: https://www.sciencedirect.com/science/article/pii/S030142071...
