Perovskite Solar PV. FINALLY some good news!

We take solar panels almost completely  for granted nowadays, don’t we? I mean they’re literally all over the place, aren’t  they? But as recently as fifteen years ago, if I’d predicted that level of market adoption  for what was then a prohibitively expensive and rather cumbersome technology, I’d have been  laughed out of the room. Some market analysts actually WERE making those kinds of predictions,  most notably a visionary called Tony Seba, who I’m sure you’ve heard of and at the time they 

WERE mostly being laughed out of rooms. Rooms that were populated predominantly by comfortable and  rather complacent representatives of the fossil fuel industry, whose strangle hold over global  energy markets at the time was absolute and unassailable. Things have changed a bit in the  interim though, haven’t they, and to paraphrase an old joke…they not laughing now, are they? You’d be forgiven for thinking that technological advancements and cost reductions in solar  photovoltaic technology ar

e nearing the end of their journey by now. I mean, there’s surely  not much road left after a price drop of more than ninety percent in ten years, is there? But  those in the know say the opposite may be true. They’re suggesting we may be on the cusp of  yet another steep market disruption S-curve. And one of the key reasons for that prediction  is a little-known material called Perovskite. So as part of our twenty-twenty-four sustainable  technology review series, I think it’s time we dived bac

k into the solar PV world to see what  all the fuss is about in twenty-twenty-four. Hello and welcome to Just Have a Think When I went back to re-watch my PREVIOUS two videos on the subject of perovskites in  solar photovoltaics as part of my preparation for this one, I realised I‘d forgotten just how  complex and mind bending the science of capturing photons to make electricity really is. Rather than  putting you good folks through the agony of yet another attempt at a fully animated and slight

ly  long-winded explanation of the intricate detail, I’ve left links in the description section  below to both of those videos, and instead I’ll just give you the ‘TLDR ‘ summary. One : Physics imposes a limit on how efficient a solar photovoltaic cell can become.  It’s all to do with which wavelengths of light physically interact with the receiving material in  the cell. Materials that absorb a very wide range of wavelengths typically only deliver a very small  voltage, and materials that produ

ce very high, and therefore very useful, voltages typically  only capture a very small range of wavelengths, which means most of the energy  in the sunlight is wasted. It’s nature’s way of having  a bit of a laugh with us. Two: The trade off between voltage and wavelength  was established in nineteen-sixty-one by two physicists called William Shockley and Hans  Joachim Queisser, and it sets the maximum theoretical efficiency of a photovoltaic cell at  about thirty percent, with silicon coming ou

t as the ideal absorber. That’s why the vast majority  of solar PV cells today are based on silicon. Three : Perovskite is an inorganic compound that  can be produced very precisely and inexpensively at low temperatures in laboratories.  It can be chemically manipulated, or ‘tuned’ capture different wavelengths of  light to silicon and it does a very nice job indeed of converting that light into electrical  energy. It is far more tolerant of imperfections in the production process and because of

  complicated reasons involving photons and phonons which you can hear all about in my  previous videos, it can be made much thinner than a silicon-based cell. A one micrometre  thick piece of perovskite film can apparently convert almost as much light to electricity  as a two hundred micrometre wafer of silicon. Four : About ten years ago, some clever science  types realised that if you applied a thin layer of perovskite film on top of a wafer of silicon  you could absorb a far wider spectrum o

f light, maintain a good working voltage, and in  theory overcome that Shockley-Queisser Limit of thirty percent efficiency. Five : In reality perovskites have mostly been a bit of a let-down really. They work  beautifully on a lab bench but as soon as you take them outside and expose them to things like  moisture and heat and…ultra violet sunlight they tend to degrade extremely quickly. It’s nature’s way of having a bit of a laugh with us! So, the challenge of the last decade, in a nutshell, ha

s been to eradicate the annoying  deficiencies of perovskite and amplify the useful advantages. When we last checked on progress, it  was a UK company called Oxford PV who looked like they’d come closest to that goal. In twenty-twenty  they were just starting to transition from years of laboratory experimentation to a full-sized  commercial version of their silicon-perovskite tandem cell, and I’m very pleased to say  that, at the time of making this video in early twenty-twenty-four not only are

they still  going, which is more than can be said for many post-pandemic enterprises, but they’ve now built  a new production line at an existing solar PV facility in Brandenburg an der Havel, near Berlin  in Germany and they are well on their way to fully automated production of a market ready panel with  an efficiency of twenty-eight-point-six percent and a proper outdoor working lifetime of somewhere  between twenty-five and thirty years. Achieving that crucial commercially acceptable longev

ity  is actually what has taken up the majority of the company’s time and money over recent years. According to Chief Technology officer, Dr Chris Case - “The biggest challenge by far is durability and reliability. We already  have great efficiency – much greater than current silicon cells – so most of our research and  development is spent enhancing reliability.” In January twenty-twenty-four the company was  featured in the Global Cleantech one hundred – an annual list of private companies mos

t  likely to make a significant market impact over the next five to ten years. The Oxford PV team are not resting on their laurels though. They reckon a  commercially affordable perovskite-silicon tandem cell will soon break through the  thirty-percent Shockley-Queisser limit and achieve cost-competitive efficiencies as high as  thirty-five percent in the not-too-distant future, which brings us neatly to a whole raft  of other contenders that have been making a lot of noise in the tech press rec

ently. Never one to miss an investment opportunity, old Bill Gates has sunk a bit of cash  into perovskites, via his Breakthrough Energy Ventures project. He’s backing a  Massachusetts-based outfit called CubicPV, who are an already well-established solar PV wafer  manufacturer. They’re developing a trade-marked technology called Direct Wafer™ manufacturing,  which apparently eliminates several of the costly and energy hungry steps in the production of light  absorbing wafers today, and instead

creates high performance versions of those wafers directly from  a bath of molten silicon. They’re now working to combine that with perovskite materials to create  their own tandem modules which they claim will offer at least a thirty percent increase in  efficiency over the very best conventional silicon modules available on the market today.  And in typically bullish free-market style they’re telling the world that they’ve got ‘the strongest  patent portfolio in North America’. In particular,

they reckon they’ve really nailed the whole  durability thing, although the explanation on their website of precisely how they’ve achieved  that elusive goal simply tells us that by using ‘better chemistry’ they have built intrinsic  stability into the material itself, making it far more robust. Which makes MY EARLIER interpretation  of TLDR look a bit like War and Peace. Anyway, the company is taking full advantage  of the financial incentives offered by the US Inflation Reduction Act and, acco

rding to this  twenty-twenty-three article in PV Tech, it’s also secured a hundred and three million dollars of  private investment towards the construction of a brand new ten-gigawatt silicon wafer production  facility that will also support the development of perovskite tandem cells. So, definitely  one to watch for the future I would say. Next up is a group based at the Helmholtz Centre  in Berlin, led by Professor Steve Albrecht. They recently published this paper explaining how a  single la

yer of organic molecules can be used as an extremely efficient additional layer to collect  charges excited by sunlight in the inorganic perovskite layer below. I’ve linked the paper in  the description section of this video so if you enjoy the challenge of making sense of complicated  scientific language then, you know – have fun! The layperson’s summary is that Albrecht’s  team has achieved efficiencies of up to thirty-two-point-five percent in a  silicon-perovskite tandem cell that retained n

inety-five percent of its initial  power after three hundred hours of operation. Their research forms part of a wider project  called Pepperoni, funded by the European Union and the Swiss federal agency SERI. The project  includes sixteen other partners with the ultimate aim of building a European pilot line for these  ultra-high efficiency perovskite-silicon cells. Another European group, led by Dr. Xin Yu Chin at  the Federal Institute of Technology in Lausanne, Switzerland, published THEIR re

search in  twenty-twenty-three explaining how they had been able to modify two different phosphonic  acids to improve the crystallization of the perovskite itself, all of which has apparently  resulted in an overall cell efficiency of thirty-one-point-two-five percent, albeit from  a laboratory cell sample that was only 9:38 one square centimetre in size and with a real-world  survival time of only about sixty-six hours. Now we couldn’t do a video about solar  PV without mentioning our friends o

ver in the Peoples Republic of China, could we? Fun fact : According to recent analysis by Bloomberg Green, just in twenty-twenty-three  alone, China installed an eye- watering two hundred and seventeen gigawatts  of additional solar capacity, smashing its own previous record of eighty-seven gigawatts  set in twenty-twenty-two and, get this, exceeding the one hundred and seventy-five gigawatts  of solar capacity that the United States has installed in its entire history! So, it should come as no

great surprise that China has got teams of people  beavering away on the perovskite challenge. One of those teams is based at the world’s largest  solar panel manufacturer, LONGi, based in Shaanxi Province. In November twenty-twenty-three  they claimed to have set a new world record of thirty-three-point nine percent efficiency for  a silicon-perovskite tandem cell, beating the previous record of thirty-three-point-seven  percent, set in May twenty-twenty-three by the King Abdullah University o

f  Science & Technology in Saudi Arabia. These thirty-percent plus claims are all  very impressive and encouraging of course, but there’s a massive caveat with all of them,  which is that they’re all coming from those tiny little one centimetre square lab-based  experimental cells, so until any of them come rolling off the end of a production line in a  real factory with a manufacturers twenty-five year warranty, it seems reasonable to suggest  that Oxford PV is surely the most convincing of the

current crop of competitors with a real  world product that you may well be able to buy for your house in the very near future. It’s not hard to see why so much furious activity in perovskite research is going on  though. As I said at the start of the video, solar PV is already the cheapest way to generate  electricity in almost every country in the world now. There’s really not much more that can be done  to make the manufacture of the panels themselves any cheaper than they already are, so th

e only  other way to keep that graph line falling is to improve the efficiency of power output from  the same sized panel, which perovskites appear to be achieving. According to analysis by market  consultants Precedence Research, the market for perovskites was worth just ninety-four million US  Dollars in twenty-twenty-two, but it’s projected to explode up to something like two-point-five  Billion dollars in the next seven or eight years, as more and more experimental research  prototypes reach

full scale production readiness. So, what d’you think then? Will perovskites  transform the market or are they just another flash in the pan? If you’ve got news and views  on the subject, then I’ll be very interested to hear them. And as always, the place to leave  them is in the comments section below here. That’s it for this week though. A massive  thank you to our Patreon supporters, for providing feedback and essential  corrections on the early-access versions of all my videos and for helpi

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Most importantly, as always, thanks very  much for watching! Have a great week, and remember to just have a think. See you next week.