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Cake day: August 2nd, 2023

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  • There’s lots of people who are pointing out that 1000x better might be misleading, which is certainly true here, but let me be a little more exact and explain things briefly (nb I’m a prof of Materials chemistry and am involved in PV research, although it’s not my main focus). Firstly, this research does not give the efficiency which is usually the headline number*. Mainly because most of their measurement aren’t using sunlight but a laser. Here they see it does interact with light to give electricity and they show the response is 1000x higher current for their new layered materials versus the unlayered type. However, as others have pointed 1000x a low number isn’t great. The highest measured current** is 0.5 mA/cm2 although they actually do proper sunlight measurements (under 1.5 suns, which is a common way to measure this) and get 0.035 mA/cm2. This is something we can compare to commercial solar cells and it’s almost exactly 100x lower than a commercial silicon solar cell (35 mA/cm2).

    Obviously there’s a lot more detail and nuance here I’m skipping over but (i) don’t expect this to change the world in the near future and (ii) its a new material approach which is cool scientifically and while the uninformed media is hyping it, the scientists in the paper were perfectly reasonable.

    If you have any other questions, I’ll try to reply ASAP.

    *RE efficiencies normal silicon ones are normally around 15%, good perovskite next-gem ones are a bit above 20%, and there’s a hard physical limit of 33% for a perfect single solar cell

    **They use uA/cm2 because their numbers are low. I’ve converted to the more common mA/cm2. These data are in Fig 3c and Fig3d. I’d recommend you have a look yourself as there’s no paywall. https://www.science.org/doi/10.1126/sciadv.abe4206





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    5 months ago

    I’m call BS. Titanium isn’t really very strong (about the same as copper when pure, while specialist Ti alloys are about halfway between aluminium and generic steel). People use titanium when they want something metal which is pretty strong but very lightweight. As an aside, it has pretty meh ductility for a metal and would make a poor bulletproof material, so David Guetta got that wrong too


  • The energy for lab grown meat has to come from somewhere - thermodynamics is always king. You can provide it via sugars/carbohydrates which the cells can motabolise, but you’ve got to put energy into making the sugar/carbs which is easiest by just growing some sugarcane/potatoes/etc. There’s more steps for meat vs plant and it’s very unlikely you can make 100 calories of lab meat with lower total system energy input than 100 calories of plant matter. (N.B., I’m a chemist, not a astronomical biologist, so if an expert refutes me and my assumptions, Place more trust in them)


  • I dont know this work, but have had a hand in some solar cell research (nanomaterials development), so can give a little context. This is a “one off” in so much as it will be centimeters sized lab based sample, although it has been repearedto verify. The current cost difference is astronomical versus mainstream (silicon) panels, but that’s typical of new discoveries. To be more exact, this is TRL 4 (technology readiness level 4) which is a scale that goes up to 9. Things only start getting cheap as you get towards the top. As for what the expected price of these materials would be, we don’t usually know for sure, although as this is a tandem cell it must be more expensive than mainstream as it literally builds a perovskite cell on top of a silicon one. They will never be used for mainstream - this is a specialist material.

    The perovskite itself might make it as a general use solar cell. They have good efficiencies and you don’t have to make pure silicon (which is a bitch) and can in theory make them cheap and easy. As for time frame, I’m a bit of a skeptic it will ever be really used as there are a couple of issues this tech needs to address before it’s viable (#1, they degrade in air and encapsulating them adds new issues) and we already build silicon factories so that is soooo cheap versus building new factories to make long-term-cheaper cells. Factories are expensive. But in theory, anyone could push it to the mainstream within a decade.