[HN Gopher] Crystal arrangement results in more power from ferro...
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Crystal arrangement results in more power from ferroelectric solar
cells
Author : vinnyglennon
Score : 251 points
Date : 2021-08-09 10:56 UTC (12 hours ago)
(HTM) web link (www.pv-magazine.com)
(TXT) w3m dump (www.pv-magazine.com)
| LeifCarrotson wrote:
| The 1000x efficiency headline is from Figure 4 of the source PDF:
|
| https://advances.sciencemag.org/content/advances/7/23/eabe42...
|
| Units are Amps per miliwatt on the Y axis and electron volts on
| the X axis. The black BTO line has a minimum of around 1x10^-10
| at 2.8 eV, which is the energy of a photon in 450 nm blue light,
| and the red SBC222 line has a minimum of around 1x10^-7. Yes, the
| difference between 10^-10 and 10^-7 is 1000x; good job, headline!
| But no, that's not the key takeaway from the article.
|
| Solar cells have an efficiency curve based on their bandgap and
| the energy in the incident light. It's theoretically a straight
| line, and regular silicon cells get pretty close to it, see the
| figure here:
|
| https://www.pveducation.org/pvcdrom/solar-cell-operation/spe...
|
| Note the units in A/W, not A/mW, also, the research is at a
| temperature of 77k, the boiling point of liquid nitrogen, while
| the above plot is close to room temperature. At 450 nm = 2.a
| silicon cell produces about 0.35 x 10^-3 A/mW, which represents
| an efficiency of something like 30% in the real world.
|
| This research and that figure 4 plot fundamentally show that
| conventional barium titanate = BaTiO3 = BTO, produces very little
| energy from 450 nm light. The researchers fixed this problem with
| a multilayer cell using strontium titanate, SrTiO3, or STO, then
| BTO, then calcium titanate, CaTiO3 or CTO, in an
| STO_2/BTO_2/CTO_2 crystal lattice stack. That's the breakthrough
| result; they were able to bridge this gap in energy output and
| take in more wavelengths of visible light.
|
| The actual efficiency of the starting point was about a million
| times worse than a good silicon cell. There's plenty of room for
| improvement when you start that low! The end result is still on
| the order of a thousand times worse than a silicon cell. A
| production dye-sensitized solar cell today reaches about 10%
| efficiency, a monocrystaline silicon cell gets about 22%, but the
| DSSC has potential to be much cheaper to produce, can be
| flexible, and is not as well understood. This research may help
| to close that efficiency gap.
| MichaelZuo wrote:
| A 1000x improvement on a baseline 1000000x worse makes sense. I
| was wondering for a bit how a PV cell could break conservation
| of energy. The article has quite a clickbait title.
| wiz21c wrote:
| I absolutely don't understand all the physics but are "barium
| titanate" and "strontium titanate" rare stuff ?
| tedsanders wrote:
| No. Depends on your definition of rare, of course. You can
| see prices for various formulations and purities if you
| Google. Strontium titanate is used for jewelry, as it was one
| of the main diamond simulants back before cubic zirconia. I
| did my PhD working with crystals of strontium titanate and
| contributed to two Wikipedia articles on it.
|
| Looking at the elemental abundances you can see that titanium
| and strontium are fairly high, above both gallium and
| arsenic, another solar cell pair. Barium is in the ballpark
| of gallium and arsenic.
|
| https://en.m.wikipedia.org/wiki/Abundance_of_the_chemical_el.
| ..
| tomcam wrote:
| That explanation was a tour de force. Thank you. You've done
| your good deed for the day!
| rikkipitt wrote:
| Reminds me of my masters research at university. My work was
| based on hybrid organic-inorganic solar devices based on boron
| subphthalocyanine chloride and an optimised optical spacer layer.
| One day, one variation of the type of cell I was producing was
| over double the output efficiency of what we usually expected.
| Was exciting until we realised the solar testing rig had been
| erroneously set to the equivalent output of two suns...
| atonse wrote:
| One day... two suns. Talk about playing God. :-)
|
| That sounds like fascinating research.
| dylan604 wrote:
| I mean, do we really need Jupiter as is? Everything Jupiter
| has done for us with clearing out the trash from the solar
| system would have been done by a 2nd smaller sun as well.
| skinkestek wrote:
| And I thought we were supposed to reduce global warming ;-)
| [deleted]
| RobertoG wrote:
| Here we are, trying to improve solar cells to avoid global
| warming, and dissidents like you want to add a sun to the
| solar system.
| [deleted]
| dylan604 wrote:
| It's not the solar system's fault that the inhabitants of
| one of the bodies in the system are bad stewards.
|
| Also, if you have 30% effeciency from the light of one
| sun, wouldn't the additional light also improve the solar
| cell since there is now more light to get 30% out of? I
| mean, more is always better, right?
| stacks_on_stack wrote:
| I know your comment is in jest, but in point of fact the
| additional heat from another star would almost certainly
| reduce the efficiency of the panels.
| edgyquant wrote:
| Can you explain why?
| edgyquant wrote:
| It'd be twice (>1<2) the energy
| ehsankia wrote:
| There's something hilarious in adding a sun so you can
| improve the efficiency of your solar panels, so that you can
| switch to renewable energy and offset warming caused by your
| current single sun (and polution).
| renrutal wrote:
| > set to the equivalent output of two suns...
|
| I didn't realize we have achieved a Kardashev Type II
| civilization already :)
| nine_k wrote:
| Achieving the effect locally for a few milliseconds has been
| possible for like 70 years now.
|
| Damn hard to get a license for that nowadays, though, no
| matter how important your science is.
| rjbwork wrote:
| Is...this a nuclear explosion joke?
| TeMPOraL wrote:
| That would be a... double-whoosh?
|
| http://wordpress.mrreid.org/2015/04/18/the-nuclear-
| double-fl...
| rikkipitt wrote:
| Haha, very good.
|
| In fact, we had some equipment similar to that on this site
| https://solarlight.com/product_category/products/solar-
| simul...
|
| Basically a super bright light source with a similar spectral
| output to our sun. A roughly 1x1cm solar cell in a nitrogen
| filled chamber is wired up to check the output under the
| incident light. Very cool production process. I was extremely
| lucky to have had the opportunity to help with the research.
| NiceWayToDoIT wrote:
| What is:
|
| Power output per m2?
|
| Durability (life span)?
|
| Production cost?
|
| At least theoretical ...
| nine_k wrote:
| They don't cite power output, but cite current output: 17 mA /
| cm2 under full sun, pretty impressive if you ask me.
|
| The key promise of this approach is "more efficient that
| silicon can even theoretically be". Overcoming the Shockley
| limit is the key finding.
| NiceWayToDoIT wrote:
| Thank you, is there any way we could find out what is
| probable life span, is it more durable
| (hailing/dust/corrosion) or less than silicon crystal? From
| time to time it would be nice if we had AMA on HN like on
| Reddit for the research team.
|
| Also mA does not says much if we do not have voltage, and I
| am not sure what full sun means as in Africa full sun can
| mean 4.5 and 6.5kWh per m2 while in Europe we can get between
| 1 and 2.5kWh per m2 or radiation.
| jbrot wrote:
| From the underlying paper[1], I found this excerpt:
|
| "The photocurrent or the short-circuit current density (JSC)
| extracted from BTO is around 0.415 mA/cm2. ... The JSC value
| from SBC555 is around 11.03 mA/cm2 and is about 25 times higher
| than measured in BTO. The open-circuit voltage (VOC) in the
| case of BTO was found to be around -0.007 V, as opposed to
| -0.058 V in SBC555."
|
| Here, BTO is the existing material and SBC555 is the new
| material from the paper. Multiplying JSC by VOC to get power
| density , we see that BTO yields 2.9 nW/cm^2, while SBC555
| yields 639.74 nW/cm^2.
|
| For reference, according to [2], we have that "typical external
| parameters of a crystalline silicon solar cell as shown are;
| Jsc [?] 35 mA/cm2, Voc up to 0.65 V." Notice the unit
| difference of mA/cm^2 here vs uA/cm^2 above. Multiplying these
| parameters yields 22,750,000 nW/cm^2. So we see that these
| cells are still approximately 100,000x worse at producing power
| than the current crystalline silicon cells.
|
| [1] https://advances.sciencemag.org/content/7/23/eabe4206
|
| [2] https://ocw.tudelft.nl/wp-
| content/uploads/solar_energy_secti...
| NiceWayToDoIT wrote:
| Thank you sir!
| thehappypm wrote:
| This type of cheeky criticism is probably fair when you have a
| startup claiming crazy numbers with no prototype, but this is
| reporting on a paper from a research institution. No need for
| snark.
| NiceWayToDoIT wrote:
| criticism, snark ?!
|
| What are you talking about?! All I am trying to get some
| numbers, if anyone has them, but it seems amount of unhelpful
| comments begins to be overwhelming on HN.
| dylan604 wrote:
| Seems like some people are unable to handle actual
| questions on anything that appears challenging and want to
| dismiss as being hyper critical and snarky for not just
| drinking the kool-aid.
|
| There was no snarky tone-of-voice in your reply when I read
| it. Maybe cultural differences? Please, kindly inform me of
| the output of the power output per m2? Also, is there any
| information available regarding the durability (lifespan)
| of the product? Who's got time to be that formal on
| something as an internet forum? I read topic, now here's
| some questions I have is perfectly fine. Some people
| possibly just need to get thicker skins and realize that
| not everyone out there is trying to be an asshole and just
| stop reading things in that manner.
| NiceWayToDoIT wrote:
| Honestly, I do not know how much technical my question
| can be, there is no tone, there is 14 words in total. I
| was googling and I could not find anything useful so I
| hoped I could get some answer from some technical person
| (material science/physic person). In my mind finding
| those number is the first thing I would do on the test
| bench, they give you prospect of technology some kind a
| range you would attract investors. You would have test
| sample 1X1cm you shine that amount of light and you get
| output. And then you know this is feasible and can help
| in future or not... simple as that. Instead I am getting
| some kind responses like I am talking with emotional
| teenagers tripping on some cry baby drugs... for heaven
| sake ... (yes that last is emotional response, I mean
| seriously what is going on with HN lately it used to be
| place with tech guys talking tech ...)
| spockz wrote:
| I suppose the tone could come exactly from the brevity.
| Imagine stepping up to a bakery and hearing "what?"
| instead of "how can I help you today dear gentleperson?".
|
| Which one would you find more snarky?
| dylan604 wrote:
| Even if the bakery employee yelled "What?" at me, I would
| not hear snark in that. I would probably hear rude, but
| not snark. I would also be a little less surprised if it
| was a very busy place and the employee was visibly
| harried by the commotion. Or if I was just in any store
| in NYC.
|
| There's a difference between terse and to the point vs
| being rude. It's not the terse response's fault the
| recipient cannot tell the difference.
|
| Also, are we using snark as a synonym for rude nowadays?
| I'm going to need to update my definitions as I was
| always understanding snark to be sarcasm. I just want to
| be using the same words as everyone else on the internet
| so I don't offend. (that was snark).
|
| Edit: actually, if I went to a store and someone asked
| "how can I help you today dear gentleperson?", I would
| immediately assume they themselves were being snarky.
| That's like saying "bless your heart". It's just dripping
| with snark.
| nepthar wrote:
| FWIW, I didn't detect any snark in your words either.
| Perhaps brevity was mistaken for snark?
| dylan604 wrote:
| For the rest of us that read no snark, please enlighten us
| into what words/phrasing led to your reading of snark in the
| parent's post. Curious minds would like to know answers to
| the actual questions posed by the parent, but also to what
| sensitivities are being upset by asking those questions.
| AndrewDucker wrote:
| The article tells you the answer to your question. Search for
| "1,000".
|
| Edit: Apologies, I misread the parent's question. I thought
| they were saying "1,000 what?". Sorry about the unhelpful
| answer.
| boboche wrote:
| Not 1000x net output since we are in what now, 10-20%
| efficiency with current available cell technology? That would
| not make sense.
| kothar wrote:
| From one of the comments on the article:
| Ryan Kennedy August 6, 2021 at 1:46 am Our
| apologies for not making this clear. The photovoltaic
| effect was increased by 1000 times compared to previous
| output achieved from cells made of ferroelectric crystals,
| not from prevailing solar cells made of silicon or other
| conventional materials.
| rob74 wrote:
| Ok, now we just need to know how ferroelectric crystals
| compare to conventional solar cells to find out what this
| "1000x" really means...
| destitude wrote:
| Yes, it would be extremely helpful if we knew how they
| compared to what people are able to purchase today.
| hansel_der wrote:
| i would guess that they are about 1000x worse than
| conventional silicon
| pama wrote:
| Or much worse yet, otherwise the authors could have used
| clear language.
| qayxc wrote:
| No it doesn't. The 1000x factor refers to the photo-response
| of the material, not power output, not cost to produce, not
| durability.
|
| All these are properties of a (prototype-)product, while this
| research is basic research and didn't create any prototypes.
| The researchers measured the photo-response by shining laser
| light onto a sample, they didn't build a panel and measured
| the power output.
| [deleted]
| madengr wrote:
| It's 1000x more than some unstated efficiency.
| qayxc wrote:
| Non of that can be answered just yet. This is basic research in
| its earliest stages.
|
| It can't even be answered theoretically, because the
| researchers are in the process of developing the theory that
| could answer these questions.
|
| So far they only made an observation and need to go on from
| there.
| [deleted]
| kilroy123 wrote:
| The other day, I watched this documentary on a huge off-shore
| wind project off the coast of the UK. It uses some of the largest
| windmills ever created.
|
| This project has a mind-boggling amount of complexities and
| involved a special large ship, one of the only kinds of its type,
| to move things around--very impressive project.
|
| It made me realize just how revolutionary solar is. Also, why it
| can compete and be so cheap compared to other forms of energy
| production.
|
| You just put this almost magical thing on your roof, and it
| silently creates green renewable energy for decades. Power plants
| can be complex and expensive buildings. Solar is just stupidly
| simply.
| jvanderbot wrote:
| I was told that an offshore oil exploration drilling operation
| costs as much as the most recent Mars rover mission ever will.
| When it comes to keeping the world moving, there's room for
| ungodly amounts of complexity.
|
| Solar cell installation is pretty easy, but there is some non-
| negligible complexity in producing them.
| wishawa wrote:
| I did a quick Google for the Power Conversion Efficiency of
| Barium Titanate based solar cells and they are currently mostly
| in single-digit percentages [1]. A thousandfold increase would be
| over 1000%. Unless I'm missing something important, they probably
| mean 1000x over a super basic BaTiO3 system, not 1000x over the
| current state of the art.
|
| [1] For example, this 5.13% PCE from "hierarchical barium
| titanate micro flowers":
| https://iopscience.iop.org/article/10.1088/2053-1591/aace86
| ghastmaster wrote:
| From the comments section of the article:
|
| > Our apologies for not making this clear. The photovoltaic
| effect was increased by 1000 times compared to previous output
| achieved from cells made of ferroelectric crystals, not from
| prevailing solar cells made of silicon or other conventional
| materials.
| phkahler wrote:
| In other words they made something work that really didn't
| before.
|
| Even if they made the best theoretically possible solar cell,
| the starting point of 1/1000th of that would not have been
| considered useful for anything.
| VygmraMGVl wrote:
| To get the 1000x figure, the research is comparing
| photocurrents from bulk BTO and their special crystal-aligned
| BTO at a specific wavelength of incident light (306nm).
|
| They also compare photocurrents under a solar simulator and
| achieve 100x increase vs bulk BTO.
|
| At no point do they make comparison to state of the art BTO
| cells, which almost certainly aren't just bulk BTO but are
| likely doped, nanostructured, or have some other novelty.
| wishawa wrote:
| That is true. The research is good. But the headline, the
| article itself, and especially this comment by the author
|
| > Our apologies for not making this clear. The photovoltaic
| effect was increased by 1000 times compared to previous
| output achieved from cells made of ferroelectric crystals,
| not from prevailing solar cells made of silicon or other
| conventional materials.
|
| misleadingly make it seem like they made 1000x _progress_
| from the current best.
| vmception wrote:
| Is 1000x from current efficiency good enough?
| nick238 wrote:
| Better title: "Extremely awful solar cell technology improved to
| be just really bad"
| JoeAltmaier wrote:
| I thought solar conversion efficiency was a large fraction
| already. There's no room for 1000x improvement. Maybe 20%. What
| is this title talking about?
| VMG wrote:
| just look for the qualifier
|
| in this case "ferroelectric"
| wlesieutre wrote:
| I think the confusion people are having with "Crystal
| arrangement results in 1,000x more power from ferroelectric
| solar cells" is that it doesn't have a qualifier like "more
| power than current ferroelectric solar cells." It only tells
| you what type the new ones are.
|
| You have to infer that it's comparing new ferroelectric cells
| to old ferroelectric cells, and not comparing new
| ferroelectric cells to our typical silicon cells.
|
| But an article doing the latter could be written with exactly
| the same title.
| binarymax wrote:
| A similar question was in the comments of the article and reply
| from the Author:
|
| ---
|
| _Ralph A Hutton August 6, 2021 at 1:40 am
|
| 1000 times? That means a normal size panel ,area about one
| square meter, that produces 200 watts , would be capable of an
| output of 200 kW. I look forward to that. I believe, and this
| needs confirming, the maximum available power from one square
| meter is about one kW. What have I misunderstood? Reply
|
| --- Ryan Kennedy August 6, 2021 at
| 1:46 am Our apologies for not making this clear.
| The photovoltaic effect was increased by 1000 times compared to
| previous output achieved from cells made of ferroelectric
| crystals, not from prevailing solar cells made of silicon or
| other conventional materials.**
|
| _
| throwaway4220 wrote:
| Can we change title to reflect this?
| MattRix wrote:
| I don't know if the title was already changed since you
| wrote this comment, but the current title of "Crystal
| arrangement results in 1,000x more power from ferroelectric
| solar cells" is accurate.
| czbond wrote:
| Can someone explain this to me like I'm 5 for me?
| Waterluvian wrote:
| This Red widget is 1000x better than older Red widget
| designs. Even though Green widgets are still much better.
| headmelted wrote:
| But red widgets might be cheaper to mass produce. Maybe.
| I don't know I'm knee deep in analogies now.
| dylan604 wrote:
| But how long do red widgets last compared to the green
| widgets? Since red widgets have been so woefully under
| performing compared to the green widgets, has anyone
| seriously looked at the red widget for long term
| viability or is this just flash in the pan type
| performance? Just to beat up the analogy further.
| connicpu wrote:
| From what the article stated, it seems the longest term
| testing they did was firing a laser at the red widget for
| 6 months straight and it maintained constant current the
| entire time
| infogulch wrote:
| Say ferroelectric crystals used to be 0.01% efficient, and
| this paper brings it to 10%. That would be an increase of
| 1000x, but still below the current best which is ~20%-30%.
| (The 0.01%/10% percentages are illustrative only, I don't
| know what is claimed in the paper.)
| karmajunkie wrote:
| the previous best output for this type of solar cell was
| nowhere near the state of the art. they found a more
| efficient structure that narrows the gap. the advantage of
| this type of solar cell is that it's potentially much
| easier to produce, but before now it's efficiency has been
| very low compared to the state of the art.
| ehsankia wrote:
| in the email above, "that produces 200 watts" is the wrong
| baseline. That's the current value for a different
| technology.
| minitoar wrote:
| The article says "the current flow was up to 1,000 times
| stronger". I don't know what that means.
| dharmab wrote:
| These are ferroelectric, rather than the more efficient silicon
| cells used for most solar energy.
| binarymax wrote:
| So, without a p-n junction, then we can break the Shockley-
| Queisser limit. Which states that in traditional photovoltaic
| cells you'll never get past 1/3rd efficiency. And until now I
| didn't even know that ferroelectric absorbers were a thing.
| Pretty amazing! https://www.nature.com/articles/nphoton.2016.143
| k__ wrote:
| For those like me, who didn't get this at first.
|
| It's about improving output from ferroelectric solar cells, a
| specific type of solar cells, which are easier to build than
| regular ones made of silicon. But they usually aren't as
| effective as the silicon ones.
| leecarraher wrote:
| yup, my thoughts exactly. otherwise a 1000x increase in 30%-ish
| efficient pv silicon-based solar cells would be far above unity
| nine_k wrote:
| Depends on how you count.
|
| If your process is 30% efficient, it wastes 70% of input. If
| you increase efficiency 1000x, it wastes 70% / 1000 = 0.007%
| of input, so it's 99.993% efficient.
| usrusr wrote:
| That would be a 1000x decrease in inefficiency. Very, very
| impressive but not even remotely as impossible as a 1000x
| increase assuming that you start with more than 0.1%.
|
| I'd expect the headline to resolve to some perspective
| where the numbers do make sense, in some very special,
| limited way, assuming that they didn't just roll dice to
| decide how many orders of magnitude to falsely claim.
|
| Unfortunately, there's a huge crowd out there that
| combines, in a surprising way, radical science scepticism
| with radical science optimism. The "science said man cannot
| fly, then came the Wright Brothers" crowd who refuse all
| painful achievable improvements based on their hope for
| some convenient miracle. These headlines are dangerous.
| danuker wrote:
| It could also mean that the ferroelectric cells were
| harvesting 0.000001% of sunlight, while now they harvest
| 0.001%.
|
| The fact that no absolute number is given in the article
| makes me want to boycott it.
| nine_k wrote:
| I'm not certain about the "easier" part, but with efficiency
| higher than a semiconductor cell _can ever be_ , this device
| should draw attention, no matter how hard is it to produce
| currently.
| k__ wrote:
| Ah, good to know.
|
| Yes, easier might be not right here, but it sounded like
| overall they are less complex.
| smolder wrote:
| Reading the article and the comments... No, these are not
| more efficient than silicon cells. They took an inefficient,
| simpler to produce PV material and found a way to
| dramatically increase its efficiency on certain wavelengths
| of light. It's still worse than silicon panels overall.
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