[HN Gopher] Mystery of high-performing solar cell materials reve...
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       Mystery of high-performing solar cell materials revealed
        
       Author : rustoo
       Score  : 90 points
       Date   : 2021-11-24 13:13 UTC (9 hours ago)
        
 (HTM) web link (www.cam.ac.uk)
 (TXT) w3m dump (www.cam.ac.uk)
        
       | photochemsyn wrote:
       | Full text report: http://arxiv-export-
       | lb.library.cornell.edu/pdf/2106.04942v1
       | 
       | The summary in the paper is perhaps clearer than the article
       | about it:
       | 
       | > "Our study has significant implications for the fundamental
       | understanding of defect tolerance in these materials and the
       | design of halide perovskite solar cells, in particular for tandem
       | cells. Using a novel suite of multimodal microscopy techniques,
       | we unveil the remarkably complex energetic landscape that charge
       | carriers must navigate in halide perovskites. We provide the
       | first nanoscale picture of how this energetic landscape
       | influences photodoping, carrier recombination and trapping."
       | 
       | > "We find that the pursuit of homogeneous chemical compositions
       | is not necessarily the best way to maximize the performance of
       | this family of semiconductors, at least while the material still
       | possesses deep trap clusters that lower device performance from
       | the radiative limits. The existence of mixed Br and I samples
       | induces the formation of beneficial local heterostructures that
       | confer enhanced defect tolerance to these materials. In these
       | regions, charge-carrier photogeneration and radiative
       | recombination occurs through a rapid wide-to-narrow bandgap
       | funneling process, more efficient than in the chemically
       | homogeneous counterparts."
       | 
       | What's really interesting is how these materials are heterogenous
       | at the nanoscale, which is rather like how the biological light-
       | harvesting protein complexes(LHC) operate, with ordered aligned
       | arrays of chlorophyll molecules held in particular orientations
       | within the protein structure that optimize funneling of photon
       | energy into reaction centers (water-splitting for H2 production).
       | 
       | However, these materials may not ever be commercially successful,
       | due to issues like lead pollution and the working lifetime of the
       | materials (they degrade fairly rapidly in full sun). Regardless,
       | this is still very useful and important basic research.
        
         | CoastalCoder wrote:
         | I know nothing about the manufacturing cost nor the lifespan of
         | these materials, but I'm curious if it would be viable to have
         | infrastructure for periodically replacing and _recycling_ the
         | panels. I.e., have regional facilities for receiving old
         | panels, re-smelting the lead and other materials, and perhaps
         | locally manufacture the replacements.
        
           | pfdietz wrote:
           | Materials cost should be significantly lower than Si or CdTe.
           | The active layer of semiconductor is just 0.3-0.4 microns
           | thick.
           | 
           | https://www.chemistryworld.com/features/the-power-of-
           | perovsk...
        
           | photochemsyn wrote:
           | This approach might work in an industrial setting for photo-
           | electrochemical applications but is highly unlikely for
           | residential or commercial power generation. mono-Si panels
           | last for decades with no need for maintenance other than
           | regular surface cleaning and no lead issues.
           | 
           | However you could, in an industrial setting, do something
           | like this:
           | 
           | "Integration of a Hydrogenase in a Lead Halide Perovskite
           | Photoelectrode for Tandem Solar Water Splitting 2020"
           | 
           | https://pubmed.ncbi.nlm.nih.gov/32010793/
           | 
           | Here you could use a catalyst regeneration strategy where you
           | basically have a little production line onsite and as each
           | unit wears out you just pop in a new one and send the old one
           | to be regenerated, that's more plausible.
        
           | Kalimoto wrote:
           | There will be no advantage of doing this locally.
           | 
           | There lifetime is too long to have enough locally and if we
           | have 100% renewable, transport will be no ecological issue
           | anymore.
        
       | pfdietz wrote:
       | > The lead salts used to make them are much more abundant [...]
       | than crystalline silicon
       | 
       | This statement fragment makes no sense. Silicon is the second
       | most abundant element in the Earth's crust, after oxygen. If it
       | means the specific form in crystalline silicon, well that doesn't
       | occur in nature, but then neither do these lead salts.
        
         | yxhuvud wrote:
         | Lead salts also tend to be a lot more toxic than silicon.
         | Putting that in something as plentiful and exposed as solar
         | panels sounds like a big potential issue.
        
           | 14 wrote:
           | I think it would be fairly trivial to recoup the lead. Add a
           | $500 deposits you get back when they are returned end of life
           | cycle. Manufacturers should eat that initial cost with
           | contract to return to them directly at end of life or they
           | charge you the $500 as per contract if you fail to return
           | them. If that doesn't scale financially then I guess it's a
           | non starter. But something as big as a panel should be easy
           | enough to recycle. Weather it is financially a viable
           | business I don't know the math of recycling one of these
           | things to even get an idea if it is possible.
        
             | moffkalast wrote:
             | This isn't a glass bottle you return next week, if you buy
             | the panels they'll last you 30 or 40 years. At that point
             | it's completely likely that the company will no longer
             | exist when you go back for your deposit lmao.
        
               | myself248 wrote:
               | It's almost like we could create organizations that last
               | longer than companies, and have the citizens' best
               | interests at heart, to administer a deposit program like
               | that. Perhaps these organizations could also govern other
               | aspects of society instead of leaving those to
               | corporations as well. Could we call them govern-ments?
        
               | baggy_trough wrote:
               | "have the citizens' best interests at heart" - citation
               | needed
        
             | pfdietz wrote:
             | There are also versions of this technology that use tin
             | instead of lead.
        
       | boringg wrote:
       | I mean cheaper technology at the same efficiency of todays solar
       | cells but available in the next decade. Interesting but not
       | changing the game. Silicon Solar will keep downward pressure over
       | that time anyways so it will need to get significantly better.
       | 
       | Lots of other options for viability im sure.
        
         | pfdietz wrote:
         | This technology will likely be rolled out as tandem cells with
         | conventional Si cells underneath. So any improvements to Si
         | cells will carry over to these, and there will always be an
         | efficiency bump vs. just Si.
        
           | boringg wrote:
           | Could be - it's a decade away, lots can change. Hopeful for
           | improvements but we've needed all this stuff like 2 decades
           | ago.
           | 
           | Better late then never I guess.
        
       | ArtWomb wrote:
       | >>> Combining a series of new microscopy techniques, the group
       | present a complete picture of the nanoscale chemical, structural
       | and optoelectronic landscape of these materials
       | 
       | It's not even relevant to call it "microscopy" anymore, we
       | require a new term. It's a complete thin film atlas of all
       | interacting forces of nature. Better data for the models, means
       | higher fidelity simulations.
       | 
       | The question is can AI predict new materials? Can a simulation be
       | sophisticated enough to predict say, high temperature
       | superconductivity in rare earth cuprate perovskites?
        
         | alteriority wrote:
         | I'm not sure if this is exactly what you're talking about, but
         | I read something a while back about using AI to predict if
         | certain metallic glass alloys will have useful properties:
         | https://phys.org/news/2018-04-artificial-intelligence-discov...
        
         | dsign wrote:
         | If we are going to speculate, then the question is, why
         | couldn't AI do it? What kind of fundamental limitation would it
         | hit? Data? But we could get a ton of data from already existing
         | software[^1]. It is slow, but I have the feeling it wouldn't
         | require as much computing as GPT-3, and it would perhaps be
         | enough to train more efficient neural networks that can do the
         | actual search.
         | 
         | Because how important is for human life, a compiler industry
         | that finds ways to translate complicated simulations to AI
         | algorithms could be the next big thing.
         | 
         | [^1]:
         | https://en.wikipedia.org/wiki/List_of_quantum_chemistry_and_...
        
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