back to article Plastic semiconductor makes solar cells more efficient

It sounds paradoxical, but reducing the amount of energy captured in a silicon solar cell can make it more efficient, according to University of Texas researchers. The research by chemist Xiaoyang Zhu addresses the problem of “hot electrons” – electrons created in a silicon solar cell that are too energetic to be useful and …


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  1. Pondule

    Sounds good technically

    But will it make me have to pay yet more subsidies to people who have the luxury of sunlight falling on their roofs?

    1. Anomalous Cowturd


      Don't be jealous of people with their own roof. I don't have one either, but this is, or could be, a quantum leap in PV development. A 50% increase in efficiency is not something to be sniffed at.

      Hope it can be cheaply implemented as soon as possible...

      1. Adam Nealis

        "Quantum Leap" Indeed!

        You do know that a "quantum leap" is unimaginably small, don't you?

        1. Jad

          RE: "Quantum Leap" Indeed!

          "You do know that a "quantum leap" is unimaginably small, don't you?"

          you do understand that the research and effort and scientific know-how that went into understanding the "Quantum" was a huge step that has changed the world of physics for ever?

        2. CaptainHook

          "Quantum Leap" Indeed!

          Please, some sometimes Sam would jump into a different sex, race, or occasionally even a different species.

          those are pretty big jumps.

        3. Scorchio!!

          Re: "Quantum Leap" Indeed!

          'It's one small leap for a man, one giant leap for mankind.'

        4. Loyal Commenter Silver badge

          @Quantum Leap

          Technically, a quantum leap is a transition of an entity between two energy levels, without ever actually possessing an intermediate amount of energy. The classic example is of an electron bound to an atom or molecule transitioning from a base state to an excited state, where the amount of energy required is small. However the meaning is not limited to this scenario, and such 'quantum leap' transitions can theoretically be of pretty much any energy, depending on the system in question.

          The metaphor refers not to the small gain that a 'quantum leap' would typically represent, but the fact that a gain, or advance has been made instantaneously without any intervening state.

          I think maybe we need a pedantic boffin icon?

    2. Matthew 3

      Not all bad

      It's true that we're stuck subsidising the folks who had a spare £10k to buy the things but it's not all bad.

      I quite like the idea that the rest of us might soon be able to go out and buy something that's twice as efficient while these folk are stuck in a 25-year outdated technology limbo (or must face giving up the subsidy).

  2. MooseNC


    A 50% increase in efficiency is like getting .5 more ounces of a 12oz steak. Not much, and it'll probably have a lot of fat on it.

    1. Nickd


      I'm pretty sure a 50% increase is actually an 18oz steak instead of a 12oz steak. Being a curious soul I slapped 12 + 50% in to google to see what the top hit was assuming you had found your percentage calculation formula that way and was briefly astonished to see it tell me I was wrong and you were right.

      A second glance showed that Google calculator is treating a 50% value as 0.5, presumably so you can say 12oz * 150% to calculate a 50% increase using the method taught to most school children.

      I hope you haven't been using Google calculator for anything important; tax returns, employee salary calculations or the effectiveness of your herbal enlargment pills for example.

      1. James Micallef Silver badge
        Thumb Up



        18 oz steak


      2. PassiveSmoking

        You fail high school mathematics forever.

        12 + (12 X 50%) = 18

        1. Danny 14


          WTF is 12x50%? is that a compounded 50%? Dear jesus i'd like one of those steaks. If John Candy could eat one i'm sure I could or at least have a good go trying.

          I'd prefer a salad though - no fries. Oh and a diet coke.

    2. Mips

      Of course.. could come work for me if I offered to increase your current pay by 50%.

      Or maybe not I need someone who can actually do maths.

    3. Pascal Monett Silver badge

      I take it that you're also against a 10% salary increase then.

    4. Francis Fish

      I think what poor old MooseNC means is

      50% more of not a lot is still not a lot. A bit like the equal pay rows of yore.

      1. Loyal Commenter Silver badge

        50% is a lot

        If the cost per KWh of conventional solar cells is 1.5 times that of electricity produced by coal-fired power stations, then a 50% increase is a VERY important development. I don't know the numbers, but I think the difference between solar and conventional cost-per-unit still works out in favour of fossil fuels, but every advance brings us closer to a world where we might be less likely to drown, starve, or die in a 'freak' weather incident because we've fucked up the climate*.

        *A note to AGW deniers: I don't care to engage you in argument; if you pull your heads out of your arses and study the science involved, rather than the rhetoric of politicians, lobby groups and irresponsible journalists, the facts of the matter stand out perfecly well.

  3. Martin Huizing

    So what you are really saying is...

    Giving the solar panels a pair of sunglasses.

  4. Muckminded
    Thumb Up

    I can't think of any technology in which a 50% increase in efficiency would be interpreted as a negative. Moose is an ass, besides being bad at math. Hopefully, he will post more.

    1. BristolBachelor Gold badge


      Depends which side of the line you live on.

      If you are an exec (or shareholder) of someone like Shell, a 50% increase in engine efficiency is not something you want to see; how will you pay for that new yacht with parking for 2 helicoptors?

  5. JohnMurray


    if I look inside the solar cells......will I see a cat..... ?

    1. serviceWithASmile


      .... and no

      1. peter 45

        See a cat? Yes and No

        I think that since you looked inside the box you have 'observed' it and collapsed the wave function. So the answer is Yes or No.

        (Yes I know that Schrödinger meant it as a ridiculous case and Niels Bohr never had in mind the observer-induced collapse of the wave function, but hey)

    2. A.A.Hamilton


      ...possibly - but you won't be able to touch it and it would be an unusually aged cat, wouldn't it?.

  6. Ken Hagan Gold badge

    Memo for patent trolls

    This is patentable. It applies to a field where people have been looking for improvements for many years, since they'd have considerable commercial value. It uses no newly discovered materials, so it *could* have been discovered many years ago. It is therefore both novel and demonstrably "non-obvious to those skilled in the art".

    BT, Apple and co. take note. This is what a truly patentable idea looks like. Study it closely. Learn, and then stop trying to patent "waiting for the cheap one to come back" and "child-proofing corners", both of which have been obvious (and practised) for the last few thousand years.

    1. Anonymous Coward
      Anonymous Coward

      "This is patentable."

      It's a discovery. Although someone's hard work went into making that discovery, and although that person should be rewarded (or, in fact, those people, all of them who contributed, which will be a very long list including people who didn't patent everything they saw in the laboratory), there's an argument that society shouldn't be awarding *monopolies* around such discoveries using some kind of pretend capitalist instrument that lots of people think is an artifact of the free market.

      And although someone could get very rich off stuff like this, there are other horses in this race (and I'm not talking about the shale gas idiocy or other "quick, it's running out!" schemes, but things in the same field as this discovery), and in any case, the last thing we want is for people to stick this kind of thing on the shelf to be revisited/rediscovered in a few decades when the organisation offering to license it doesn't want to charge quite as much.

  7. Michael H.F. Wilkinson Silver badge

    So zey are uzink ze dark quantum state, are zey?

    Next, zey will be uzink ze dark light itself!!!!!!! (cue roll of thunder)

    It vill all end in tears!!!

    Otto von Chriek

  8. Bernt Oestergaard

    Reflected light is a much bigger solar energy problem

    The solar efficiency record is today around 42% and going on 50%, so the theoretical max. claims by this research seem somewhat outdated – also because solar cells lose effect fast with rising temperatures. Rather, I would expect significant solar energy efficiency gains to come from better optics because the refractive index on solar cells is 3.5 and its has not yet been possible to produce a surface with a graded refractive index between 1 and 3.5 which would lead all incoming light to the solar cells. Solving this problem would stem the considerable loss of energy in today’s systems. A beer to the research that solves this issue!

    1. John Smith 19 Gold badge

      @Bernt Oestergaard

      "The solar efficiency record is today around 42% and going on 50%, so the theoretical max. claims by this research seem somewhat outdated "

      I think you'll find those figures are for cells with *multiple* junctions with somewhat exotic materials combinations and mfg methods IE space grade types.

      They are *nothing* like the kinds that are in common use for terrestrial applications.

      As for reflectivity I seem to recall when one of the US mfg started *seriously* rampping up production one of the things they did was to do a surface etc on their single crystal cells to give them pyramidal pits to act as an anti reflective coating.

      Not universally applicable but demonstrates that sometime the smoothest surface is not the best.

      But I'll certainly raise a glass to anything that can do AR coating effectively and cheaply.

      1. Frank Bough

        You're right

        the latest big thing in the world of camera optics is the 'nano-crystal' AR coating.

        see here:

        might be too fragile for use in PV arrays, though

      2. serviceWithASmile


        you *could* paint it matt black

        1. Parax


          If it were 100% efficient at capturing photons it would be matt black anyway... the kind of eerie matt black that you cant see, and cant judge a distance too..

  9. James Micallef Silver badge
    Thumb Up

    Fantastic, this really is a big deal. Panels at approx 25% efficiency in sunny places like Spain or California are already pushing close to cost-parity with oil generators, even more so if the price of oil stays around or over the $100 mark.

    1. Anonymous Coward
      Anonymous Coward


      If it's both sunny and cool, and then it's a stretch.

      1. Loyal Commenter Silver badge


        The intersting thing about this advance (if it is the same one I read about in NS a few weeks ago), is that it captures the 'hot' electrons, which are part of the problem of reduced efficiencies when panels get hotter, so it actually improves efficiency on two fronts - capturing energy from otherwise 'lost' photons, and reducing the effect that 'losing' those photons as heat has on the cells, thus adjusting the temperature equlibrium between the cells and their environment. An added advantage is that the materials involved are cheap (much cheaper than the materials the cell itself is made from), and form a protective layer on top of the cell. All in all, it's a very nifty solution that tackles several problems with solar PV in one bite.

        1. Anonymous Coward
          Anonymous Coward

          Agreed, and I'm interested to see it in practice. My criticism was to the optimistic 25% efficiency of currently installed panels, even in the sunnier climes of Spain and Cali.

  10. Tom 7

    Me - I'm waiting for the 5% efficient printed stuff.

    A whole side of a roof (50m2) of that should cost (installed) a lot less than 2m2 of 'high efficiency' stuff but generate nearly twice as much power. And should save the cost of tiles on a new install.

    Efficiency is pointless when we really want in the end is cheaper electricity and we have the space to do it - and we could achieve it by mass producing the polysilicon 12% efficient cells of the 80's.

    I'm not trying to knock the great achievement they've made but we seem to have lost our way in renewables - and probably production in general - think how much a 1m2 windmill with blades made of pressed metal with something akin to a car alternator would cost - £100 maybe. Stick it on your house roof. You'll get maybe 1/3rd the energy you get from something that costs 5 times as much - and that's before you stick it on a very tall pole in a field.

    1. Loyal Commenter Silver badge

      Of course,

      if you mass-produced the 12% efficient polysilicon cells and treated them with this method, it would make them 18% efficient.

    2. Giles Jones Gold badge

      Most solar or wind turbine solutions you can buy will take around 25-50 years to recoup the investment. Given that the average first time buyer is in their mid 30s it seems like a poor investment.

      Better to improve the insulation in your home, that's cheap and can save a reasonable amount per year. If you already have a lot of insulation there's always triple glazing.

      1. Keith 12

        25 years?

        A friend of mine, just a few houses away, had installed a 3kw installation for £8500 and is bringing in £1400 a year, though of course the FIT has been reduced by over 50%, and we do live on the S.E. Coast, that's still a lot less than 25 years.....

        1. Richard 12 Silver badge

          Which would be approx. £370 p/a at the domestic electricity price (12p/kWh)

          23 year payback period for 20 or 25-year rated panels and 10 year inverter.

          Or somewhere in the region of £150-200 at the commercial generation spot prices (~6p/kWh), a more than 40 year payback period. Try that with your bank manager.

          They're getting that much *entirely* due to the domestic subsidy of 45.5p/kWh total.

          Assuming your figures are accurate, they have generated approx. 3000kWh p/a this year.

          Thus they are taking somewhere between £1000 and £1250 out of the pockets of everyone who does not have a solar PV array installed - eg those who don't own their property and those who don't have access to that much liquid capital.

          If the subsidy does actually drop by 50%*, that means 23.75 p/kWh, so they'd receive about £700 and only be taking £400 out of your (and my) pockets each year.

          This new breakthrough is a really good example of why this subsidy is stupid - solar PV is still new, still evolving. If that money went into research instead of the pockets of the better-off then we might actually get commercially viable solar PV or other renewable systems.

          *There's a court action by the solar PV installation industry, who know damn well that without the insane FIT they are screwed. It's never been green, it's always been about money.

          1. Keith 12

            Wake up - deal with it ffs!

            Richard12 "They're getting that much *entirely* due to the domestic subsidy of 45.5p/kWh total."

            Yes, thats right, that's the world your living in, - I responded to the comment regarding a 25 + year payback, based on the above thats rubbish. Your diatribe completely fails to refute my comment.

            Wake up and smell the coffee before its too late............

            1. Richard 12 Silver badge

              Likewise. Do you think that tariff is really going to stay?

              It will be gone in five years as it is obviously unaffordable.

              The cracks have already appeared - the pot of money set aside is already exhausted, which is why they are cutting it early - and it is in fact the reason why the last round of electricity price rises happened.

              (Admittedly it's not just the solar PV FIT, the wind one has a similar effect.)

              1. Anonymous Coward
                Anonymous Coward

                @ "Do you think that tariff is really going to stay?"

                yes it will, it's a 25 year contract. New installs will get whatever the reduced rate is, as you pointed out the pot (i.e. all the £15s of each energy payer so clearly not the reason for the massive electric price hikes) is running out, so new installs will be limited by slashing the tariff - it needed to happen but more notice should have been given.

                Plenty of people buy cars on finance but then whinge about it not being fair, I don't have the money to put panels on my roof. Well my cars 10 years old, but my panels are nice and shiny ;)

      2. C 2

        Another option..

        If you're looking at the most effective way of saving or capturing energy for the money spent consider building a cheap solar space heater. The *most* effective value for the money spent I have seen is to build large panels using 2 or 3 layers of black aluminum window screen as the collector. Basically this stuff has the maximum surface area per Kg/ pound / whatever, so that as its temperature goes up, it heats the air around it very quickly. Convection does the rest, or a small fan (powered by a small PV panel) can assist.

        I found a comparison of several designs here:

        More collected data here:

  11. Lee Port
    Thumb Up

    To all all those folks that have subsidised my recent PV installation .. thanks !

    1. Anonymous Coward
      Anonymous Coward

      What's next on your list: the moat or the duck island?

    2. Anonymous Coward
      Anonymous Coward

      Thanks from me too, less than a year and already up to £1500. CHA CHING.

      I await all the jealous down votes and whinging and whining from the usual crowd about middle class this and that. And I expect some complaining about not being able to afford the outlay, or to put the heating on, or your monthly sky sports, movies, full package.

      Flame away

      1. Figgus

        Interesting. On this side of the pond, the rich subsidize the poor.

        No, I don't think it works any better either way.

      2. Anonymous Coward
        Anonymous Coward

        I hope the drop in FIT chokes you

        And that you enjoy the pitchfork through your chest once the plebs realise that the shiny thing on your roof is the reason they can't afford their electricity bills anymore and had to resort to flaming torches.

        More seriously, I hope you enjoy the rolling blackouts you are (partly) causing in the next decade.

        1. Anonymous Coward
          Anonymous Coward

          @"I hope the drop in FIT chokes you"

          No drop, only inflation (the good one not the lower one) raises for me. Price drop is for new installs after December. Helps to actually read up on the subject.

          I fail to see how the £15 your bill goes up to subsidise us rich FIT folks has anything to do with not affording the increased electric bill. Again it helps to actually read up on the subject. But if it genuinely gets bad for you I dare say I'll be subsidising you through my tax anyway. And as for the death threat, should that occur there will be less tax to pay for your sky subscription, so while I might die, you will have to learn to read (or watch repeats on terrestrial).

          As for enjoying rolling blackouts, should this event you have imagined actually occur I will merely install some batteries and divert my excess solar power there for night time use. Again try thinking it through next time.

          As I'm sure you have received many times throughout your school life.

          Attainment: F

          Effort: B-

          1. Anonymous Coward
            Anonymous Coward

            It went up by quite a lot more than 15 quid.

            And that's going to happen every single year, at an increasing rate well above inflation, primarily forced by the FITs for wind and solar.

            These energy price increases are going to have a much bigger effect than you think - it's not just my electricity cost that goes up, it's everyones.

            Including the shops I buy stuff from, the warehouses they are stored in, the last few British factories they're made in (which will of course go overseas once energy bills get too high), the local council and the place where I work.

            Thus my electricity bill goes up, my shopping bill goes up, my council tax goes up and my wages go down.

            The Bank of England agrees - Energy price increases are the current prime driver of inflation - thus these FITs are ****ing stupid.

            As to the rolling blackouts - read the National Grid report on the target high penetration of wind and solar by 2020. It says a lot about the need for extensive "demand management", which means blackouts. Batteries won't help you much - you're not generating enough to go off-grid unless your install is a lot bigger than the usual domestic ones.

            (Incidentally, I don't have Sky or cable TV.)

            1. Anonymous Coward
              Anonymous Coward

              FIT is not the sole reason for energy price increases

              I never said the electric bills went up by only 15 quid, I stated that that the FIT amount of the increase was only £15, the rest is greed/wholesale market prices honest guv/whatever the energy companies excuses are, some is for wind and ROCs yes but this article is about Solar and FIT.

              Yes energy price increases are an issue, but to throw your toys out of the pram and to blame it all on FIT is ridiculous. Incidentally I'm not some green nut job, I've switched to EDF for cheaper electric, I know they are French but it's not my fault we aren't investing in cheap nuclear and they have.

              You said rolling blackouts not complete grid failure, so I can cope off grid for a bit at a time no problem. Anyway I'm generating 90% of my annual consumption so I'm reasonably sufficient, winter might be an issue as I can't store all the excess from the summer for the winter months, but the heating is gas and I can generate enough in winter to run the electric pump for the radiators so meh.

  12. Brewster's Angle Grinder Silver badge

    Thanks for explaining what holes are...

    ...but first I need you to explain what electrons are. *facepalm*

    OTOH I would have welcomed an explanation of 'dark quantum “shadow state”'.

  13. Is it me?

    Paradoxical, not to me.

    Not sure that it's true to say that this seems paradoxical. If you think about it, there are many things that decrease in efficiency as input goes up. If you stick too many electrons down a wire, the wire will heat up, decrease in efficiency and ultimately fail, same applies to water in a pipe or messages in an ethernet cable, although the latter does not fail quite so spectacularly.

    If you can dissipate the waste or control the input, you can get maximum efficiency, better still if you can "cool" your wire then capacity and efficiency can then increase, until super conductivity.

    Warning, don't try this teqnique on water pipes, as that would be akin to cooling your wire to absolute 0, in which case all bets are off, and something will break.

    Note to hardened physacists - Yes I know, but I'm employing Dark technology.

  14. Lee Port

    Hold on ...

    I'm worried this use of Dark Technology might well precede a Rise of the Sith

    1. NomNomNom

      I find your lack of faith disturbing

  15. Andy 18

    How long does plastic last in the sun?

    Not sure why there is an argument about what 50% is. From 20% to 44% is over a 100% increase in efficiency (using newspaper language) or a 24% increase in efficiency to anyone with a brain.

    I do wonder what the effect of UV light on pentacene would be. Most plastics left outside barely last 5 years.

    1. Richard 12 Silver badge

      Gah! I hate this...

      20% to 44% is a >100% increase in efficiency, or a 24 percentage point increase.

      The difference is extremely important!

      As an example, if your 5% AER mortgage interest rate goes up by "10%" then you are going to care whether it's gone up to 5.5% or 15% AER.

      (If it's gone up by 10 percentage points then you probably need to remortgage, and quickly!)

  16. CaveatVenditor

    It might be too simple

    but why not have solar PV elements interspersed with solar thermal elements to cool them? That would extract every last drop of energy and the cat would be safe.

    Oh bugger that's yet another brilliant idea I've given away.

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