Infrared Solar Cells Will Boost Solar Power by Up to 25% and Eventually Double

A research team led by Hans Ågren, professor in theoretical chemistry at KTH Royal Institute of Technology, has developed a film that can be applied on top of ordinary solar cells, which would enable them to use infrared light in energy conversion and increase efficiency by 10 percent or more.

“We have achieved a 10 percent increase in efficiency without yet optimizing the technology,” Ågren says. “With a little more work, we estimate that a 20 to 25 percent increase in efficiency could be achieved.”

Photosensitive materials used in solar cells, such as the mineral perovskite, have a limited ability to respond to infrared light. The solution, developed with KTH researchers Haichun Liu and Qingyun Liu, was to combine nanocrystals with chains of microlenses.

“The ability of the microlenses to concentrate light allows the nanoparticles to convert the weak IR light radiation to visibile light useful for solar cells,” Ågren says.

Invisible infrared light accounts for half of all solar radiation on the Earth’s surface, yet ordinary solar energy systems have limited ability in converting it to power.

Lanthanide photon upconversion nanoparticles (UCNPs) generally exhibit a nonlinear response to excitation light, featuring a higher quantum efficiency at a higher excitation intensity. Thus, effective excitation light concentrators, whenever feasible, are preferred, to make better use of the photon-upconverting capacity of UCNPs. Here, we explored polymer microlens arrays (MLAs) as light concentrators for irradiating UCNPs and investigated their spatial light modulation effect on the resulting upconversion luminescence (UCL). It was found that a piece of MLA can potentially concentrate excitation light by orders of magnitude, subject to its structure and optical properties, and lead to a very significant enhancement of the UCL. MLAs can be easily incorporated into different types of UCNP-enhanced photonic devices, such as dye-sensitized solar cells, and bring further performance improvement in the near infrared range. A test on a dye-sensitized solar cell proved this contention, however, there is much room for optimizing a variety of parameters both for the solar cells and for the light concentrating upconverting layers to make the combined effects even more significant.

Nanoscale – Microlens array enhanced upconversion luminescence at low excitation irradiance†.

The dearth of high upconversion luminescence (UCL) intensity at low excitation irradiance hinders the prevalent application of lanthanide-doped upconversion nanoparticles (UCNPs) in many fields ranging from optical bioimaging to photovoltaics. In this work, we propose to use microlens arrays (MLAs) as spatial light modulators to manipulate the distribution of excitation light fields in order to increase UCL, taking advantage of its nonlinear response to the excitation irradiance. We show that multicolored UCL from NaYF4:Yb3+,Er3+@NaYF4:Yb3+,Nd3+ and NaYF4:Yb3+,Tm3+@NaYF4:Yb3+,Nd3+ core/shell UCNPs can be increased by more than one order of magnitude under either 980 or 808 nm excitation, by simply placing a polymeric MLA onto the top of these samples. The observed typical green (525/540 nm) and red (654 nm) UCL bands from Er3+ and a blue (450/475 nm) UCL band from Tm3+ exhibit distinct enhancement factors due to their different multi-photon processes. Importantly, our ray tracing simulation reveals that the MLA is able to spatially confine the excitation light (980 and 808 nm) by orders of magnitude, thus amplifying UCL by more than 225-fold (the 450 nm UCL band of Tm3+) at low excitation irradiance. The proposed MLA method has immediate ramifications for the improved performance of all types of UCNP-based devices, such as UCNP-enhanced dye sensitized solar cells demonstrated here.

51 thoughts on “Infrared Solar Cells Will Boost Solar Power by Up to 25% and Eventually Double”

  1. Just about every road outside of built up areas has a speed limit of 100 (Victoria) to 130 kph (Northern Territory). People get on and off them just fine. Most of the time.

    You just have to use your eyes and brain a tiny bit.

  2. I suppose you could argue that you don’t need these things, but Canada has about a third more population and has 16,900 km of “expressways”. Canada has 1km/2224 persons. The US is only at 1km/3018 persons. But I am guessing that if every lane was counted, theirs and ours, we would have more per person. But it is probably pretty close.

  3. Went to google maps that is a little 2 lane thing with a line in the middle. We probably have 4 million miles of that stuff.

  4. If there are no on-ramps and off-ramps, it really is not a highway to Americans (or at least Californians).
    Also, practically speaking it would be very dangerous getting on and off a road where the speed limit is anywhere from 65mph (105kmph) to 85mph (137kph) without on-ramps and off-ramps. And a highway generally has at least 2 lanes going each direction. And you have to consider that most Americans go at least 5 mph faster than the limit. I was on the Interstate 15 a couple Saturdays ago. Everyone was doing at least 85 mph. And I do mean everyone. And there were plenty going 100 mph+.

  5. Newspaper? Oh, that was when they used to print out a selection of the internet from yesterday and physically bring it around to your house.

    My grandfather told me about that, it was popular before people had internet connections at home.

    I hear some of the old fashioned news websites still offer this as a service for their customers that enjoy cosplaying at the 19th century.

  6. Australia has only 3, 132 km of highway? That is not correct.
    That would be about the distance of following only the Highway 1 from the start at Cairns down to Melbourne. That single highway route continues for another 12,000 km after that.

    Looking at your reference it seems to be counting only Expressways, defined as

    A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow ingress- and egress-regulated.

    At which point the issue is that the USA is more in favour of restricting on-ramps, not in favour of roads.

  7. Since the surface of all photovoltaic panels are already dark by design, their solar infrared waste-heat by-product could easily be harvested using century old thermionic technology. Thermionics simply requires two dissimilar metals with a thermal gradient and a dielectric layer between them to create a potential current. Newer adaptations of the tech provide for reversible systems using PNP and NPN layers comparable to modern solar arrays. Existing PV panels are generally constructed on aluminum surfaces that readily harness solar thermal energy and which can be modified in design and clad bonded on their underside with a more Peltier-friendly metal foil. Providing a transparent insulative layer on the surface of the PV panel would also help channel the thermal energy out the bottom layer. A second (dissimilar metal) isolated foil metal layer beneath the panel would serve as the cooling face. A passive (finned) and/or active (micro fan driven) cooling system on the bottom layer would also increase process efficiency.

  8. Also, important question: at what cost increment per net efficiency gain? Likely tiny gain at significantly increased $/W cost.

  9. And these things don’t just automatically happen just slower. Most countries don’t have highways or may have just a few hundred miles, and I am not talking poor countries…the vast majority: 132 countries have 0 km of highway. Another 44 countries have less than 1,000 km. Only 12 have more than 5,000 km. We have 108,394 km.
    Australia has just 3,132 km. New Zealand 199 km. Russia 2,064 km.
    We never had a government project to go up the west coast with a rail. Guess what? We still don’t. Should have been done decades to maybe 150 years ago. In fact, sometimes government has impeded the public good in infrastructure. The Owen’s valley water project and the LA aqueduct was conceived to provide both LA and San Diego with water. Some judge prevented them from ever selling it to San Diego. And San Diego has never had enough water as a result. And the water we do get is very low quality. It was only when we built a reverse osmosis desalination plant that the extreme water conservation measures could be eased. And there are dozens of examples of the highway system not being expanded when housing developments were built causing enormous congestion, waste and inefficiency. People are more likely to see building these necessary highways as some sort of handout to the developers, ignoring that it is the residents that need these highways and that we are all worse off from congestion.

  10. 20% increase of efficiency means to multiply times 1.2 the efficiency. In other words efficiency raise from 20% to 24%

  11. Entire industries are built to create ~20% cells – both types of silicon, CdTe, CIGS and the rest of commercialised tech. If some new cell offers a potential improvement for, say, 20%, that will not change the fact that the market is filled to capacity already. Investors sit on 30-years business plans with billion-dollar debts attached to all that. Also, importantly, it was filled at the time of government subsidies, which now over. Unless the new cell doubles or triples the economic efficiency, as in breakeven in 2 years versus 5 years, the industry and finance will not write off everything just to switch to the new.

  12. Stuffing a solar concentrator before a frequency converter works, part deux. I imagine this might work better if you prismatically split the IR off, or use a dichroic mirror before ffeeding your concentrator array.

  13. The anwer is in logistical curve. For solar, it is now well into its right corner. They can keep messing with it forever, with increasingly diminishing return on investment. That is what usually stops people: realisation of malinvestment. No one is investing now in creation of a 500hp horse – there are motorcycles with 500hp engines, even tanks of the old did well with that power. That is the wisdom of logistical curve: feasibility of improvement ends long before possibilities for improvement end. Solar is past that point.

  14. IIRC, the solar cells themselves now only make up ~50% of the total installed cost of solar. The rest goes to infrastructure, labor, etc. Not sure what’s happened with multi-junction processes lately but it might be worth looking into again. If you could increase efficiency from 24% up to 30% while only seeing a 20% increase in cell cost you actually see… math… about a 30% reduction in total installed cost? 5% reduction cell cost per watt and a 25% reduction in “everything else” per watt.

  15. Solar panels only do like 20 percent, so of that baseline. Otherwise they’d be patting themselves on the back about how their nanolayer contributes more than the panel itself.

    So 20 increased to 22-25.

  16. True, but the children of the kids breathing tetraethyl lead in the seventies, or soot in the 1880s, will mostly not be affected. Their great great grandchildren will still be dealing with about half the accumulated CO2 of all of them.

  17. When did the cost of extracting HC magically decrease? As far as I can see the HC resources are getting more and more marginal and the cost of extraction is getting more and more expensive.

  18. Most to all of the actual negative effects to date from HC engines have been carbon monoxide, soot, volatile organics, nitrous oxides, sulphur compounds, lead compounds and stuff like that.

    Which are spectacularly cleaner in 2019 than even 1990, let alone 1960. I mean literally orders of magnitude cleaner.

  19. As I was saying the Interstate Highway System has been a major asset contributing a great deal to US productivity. This was done under Eisenhower not some heavy spending Democratic regime.
    Without investment we stand still. That said, we can’t just spend and get nothing for our money…we have to get things that actually pay off. We work best in competition. Every contract should be won by at least 2 companies where one can seize a larger share by doing a faster and better job. Just as that Transcontinental railroad was done. The Human Genome Project ended up a little like that too. And that was way ahead of schedule and much cheaper than projected.

  20. There are some things where subsidies make sense. These are things that increase productivity and/or reduce costs long term: energy, transportation, water, agricultural technology, information (AKA science/engineering), education, health, communication (and the provision of a variety of national statistics), safety, mining technology, and to some extent manufacturing, though the only manufacturing technology we are fostering at the moment is military…and though lots of dollars are invested, we have become complacent about getting anything like value from that investment.
    And this in not just something from the FDR era. The US has a long history of this kind of investment. Consider The First Continental Railroad 1n the 1860s or the Reclamation Act of 1902, and several similar projects quickly following, bringing water to the western States. These investments lead to California growing vast amounts of vegetables and fruits not really easily grown on the more naturally watered areas. Transcontinental rail facilitated increased trade and further development in the west. The NIH got its start a long time ago. It started as the MHS which had been established in 1798 to provide for the medical care of merchant seamen. But was mostly directed at reducing the spread of disease from these sailors to the US like cholera and yellow fever controlling epidemics. The Interstate Highway System has been a major asset..

  21. If they keep messing around long enough, they’ll eventually get the point where things are both practical and better, so I say more power to them. Note, none of this stops people from using what’s most cost effective today.

  22. Population doesn’t seem to be increasing all that fast in developed countries. In fact if you ignore immigration, it’s declining. This is good news since the developed world has the largest per-capita energy consumption and can afford to get much greener. As the rest of the word develops the trend will hopefully continue. Will this be fast enough to eliminate the risk of climate change? I doubt it therefore we in the developed world need to double down on our own efforts and additionally subsidize green energy in the those countries on the cusp of becoming developed.

  23. Politics change. The technology is already here. Prime Genome Editing in particular looks really promising. 200+ countries and not one will be interested in making their children healthier in decades to centuries?
    That is way more far fetched than anything I have said.

  24. I didn’t reference fusion for the purpose of implying it was better, but rather to emphasize the timescale of any advanced degree of genetic modification of humans – ie fusion may be taking forever, but it will still happen before advanced GM humans do.

  25. I am not optimistic about fusion. Fission does everything we could want…in the new forms…such as molten salt. Fusion in whatever form will be expensive because the plants will almost certainly be very expensive. And they will definitely be very expensive if they are plasma confinement. Fusion for space transport because of better energy/mass might be a thing. But as sci-fi as it sounds I think antimatter propulsion will be greatly preferred and would certainly take over once developed.

  26. The research in thermophotovoltaics (TPV, PV using infrared from heat, typically around 800-2000C) is much farther along, see research published this June; “For the past 15 years, the efficiency of converting heat into electricity with thermovoltaics has been stalled at 23 percent. But a groundbreaking physical insight has allowed researchers to raise this efficiency to 29 percent. Using a novel design, the researchers are now aiming to reach 50 percent efficiency in the near future .”

    Microlens arrays may be part of such a system, but not made out of polymers, and most likely using cylindrical lens, line-focus designs.

    TPV is a promising candidate for small, high-power- and energy- density combustion generators for drone, aircraft, powered exoskeleton and other military uses. It can also be combined with molten salt or metal heat storage systems for load-balancing solar thermal power.

    The original article on the 29% efficient TPV:

  27. Residential energy use should be very low with what I have suggested above. 90% of your body energy is used in thermal regulation. If you are effectively coldblooded you need just 2-3 ordinary meals a week. Less dish washing. Probably would not even have a kitchen. Just eat out those meals.
    You will rarely sweat, so clothing will stay cleaner and so will you. They will probably delete the genes that cause body odor. Who needs them? Some Chinese already have the gene silenced. It comes at a cost currently, making the wax in the ears dry and more likely to cause buildup and infection, but these effects can probably be separated. If you don’t smell, and don’t sweat, you probably don’t need to shower daily. Clothing don’t necessarily have to be washed after being worn once either. That is saved water and energy. Heating energy would not be necessary. Cooling energy would not be needed. Electronics are becoming more efficient as components shrink. If they really worked to reduce power for electronics the power could be very low. And even the stuff with displays could use very low energy as eyes could see the lower light levels. By my estimates, energy use could be at well under 1/10 current levels. Perhaps 1/100. At least for that basic human support/residential use. Industrial stuff would still take lots of power, space transportation would take lots of power…

  28. While human efficiency is not really on the radar for genetic modification, that can change. And not just because we are desperate. I think it will be a cheap and easy thing to do…and important for space travel. At least the borrowed genes to remove the need to be homeotherms (which will likely be done anyway because it should extend lifespans hundreds of years). Seeing in much dimmer light is similarly likely an easily borrowed modification (many species have a reflective layer that effectively doubles light availability for the retina. then there are larger pupils…we could have eyes like owls).
    When we use cars to transport ourselves, the energy wasted is very large. And it is not just that car powertrains are 15% efficient. It is the fact that you are moving 2 tones when it is your 175 lb body that is really what is desired to be transported. You also assume that we can’t be paid for the amount of work that is done rather than the time. Much less oversight required if you are paid that way. And telepresence using robots was what I was talking about. No reason you couldn’t operate a very capable robot from your home to do a job at a job site in the future. Though, AI will probably have you directing a dozen rather than one in detail…or one or another in detail switching you about.

  29. Jevon’s Paradox doesn’t always apply.

    E.g. The price of electricity is often highly regulated and very unlikely to fall if consumers cut their consumption 10% – so no one else is likely to increase their demand as a result of market forces that are blocked by the regulation. Instead, the regulated price would eventually be allowed to increase a bit to maintain the power companies’ profits.

    Also, new consumption isn’t the only way markets can react to decreased demand. In a market where supply can fall quickly as prices fall due to lower demand, but new consumption takes time to ramp up, consumption falling would result in supply contracting to keep the price nearly the same, which means less stimulus for new consumption.

    And sometimes new resources substitute for old – demand for horses fell greatly with the availability of cars and trucks and tractors, but those who formerly couldn’t afford horses didn’t buy up enough horses to maintain ‘horse consumption’ at the old levels. Nuclear power or wind/solar+battery might get cheap enough to eliminate coal globally. Electric cars may be attractive enough to eventually eliminate the market for gasoline.

  30. I haven’t heard of any mention of OTEC since I was a little boy.
    A brief internet search shows there are a couple of small research stations with one or two going up to 100 kW, but doesn’t seem to be much going on.

  31. The academia is busy making “paper reactors”. A few percent of a percent added to performance at the cost of probably doubling or more the cost of production for inexpensive roll-to-roll cells. As for expensive cells, it was done long ago: germanium substrate under 3~5 junctions, each optimised for a narrow part of solar spectrum. The result is 39%+ cell efficiency. Such cells cost arm, leg and three kidneys, but for GEO satellites it pays off in weight savings. There is nothing to pay it off with in cost-optimised applications. If one wants performance at extra cost, there is concentrator cells with ~50% efficiency, with extra cost going into heliostat, optics and thermal management. The NREL result is 47%+ cell efficiency in a six-junction cell with 143 concentration factor.

  32. First off, modification of the human body/genome in the ways that you describe is so far off realistically that it’s pretty likely we will have squeezed every last drop out of solar and battery tech – to say nothing of finally cracking significant net gain fusion.

    As to the telepresence mention, that only applies to telecommuting for non work – it does nothing for all the other necessary uses of power for transportation.
    Even then, there are many industries where telepresence simply won’t be viable, such as those relying on physical work and actual human presence (hospitality industry) – and most employers prefer their employees where they can see them actually doing their jobs if preferable, for these reasons telepresence will never have the impact you think it will.

    AI and advanced robotics replacing human workers on the other hand would definitely have a dramatic effect on workplace energy consumption and efficiency.

    Per the 80% efficient chloroplast comment, there is more to the problem of photosynthesis efficiency than chloroplasts themselves – light is scattered by the cell walls of plants, which is already thicker than the cell membrane of most animals.
    Just as with LED’s, OLED’s and Quantum Dots, you have to worry about getting the light/photons to the energy producing elements with minimum scattering, and then from those elements to the body.

  33. On one level, I agree. Humanity will use more and more power. However, it may be that it will take less and less power to support basic human needs. If we can synthesize food at only a fraction of the energy cost above the bond energy in the food, that would be many times less energy than we currently use to get food on your plate. Telepresence can use far less energy than transportation. Even the human body can be modified so that even extreme temperatures, cold or hot, do not discomfort us…so we require no heating or cooling. We might even be able to see with a small fraction of the light needed now. It is even possible that we could get energy from the sun via our skin. Plants are only about 3-6% efficient. If we could engineer chloroplasts that were say 80% efficient, integrate them into your skin and you were not a homeotherm, that should provide ample energy.

  34. Have a look at Nature 571,(38,90) ( July 4, 2019). It reports on simple hydrocarbon layer that can split a photon into two electron/hole pairs. The article talks about 133 % absorption by a solar cell, and that’s a fun number when talking to unimaginative people.

  35. I take that back. Whenever it is unclear whether the increase is i percent or percent points, it is always percent.

  36. ‘China isn’t waiting – they are subsidizing solar very, very heavily.’
    Not so much any more.
    ‘China’s new solar installations hit a record 53 GW in 2017, but slowed to 41 GW in 2018 after the government announced a massive scaling-back of subsidies in order to ease pressures on the transmission system and reduce a subsidy payment backlog estimated at more than 100 billion yuan ($14 billion).
    New additions hit 11.4 GW in the first half of this year, and Luo said it was highly unlikely that would increase in the second half.
    Most new installations in 2019 have been unsubsidized, and that was now the industry norm, he said.  ‘- Reuters 6/9/2019

  37. ‘ HCs are … getting cleaner all the time.’ Only marginally – burn a fuel with carbon in it, you’ll get about the same energy, and 3.6 x the mass of CO2.

  38. I have solar on my home, that said, baseload needs to go nuclear to allow society to exist. Battery backup for downtown NY just looks bad.

  39. Massively reducing energy consumption will never happen.

    Jevons Paradox combined with a growing population means it simply just won’t happen.

    However, that doesn’t in any way make hydrocarbons an automatic solution, not when nuclear has so much potential – newer compact modular reactor designs (IMSR for instance) will be much safer than anything previously used, and much cheaper and easier to make at the same time.

  40. Solar energy doesn’t have to fully replace hydrocarbons, it only has to provide a significant offset (to reduce HC emissions), and it seems pretty clear that this is not only possible, but already in progress. In 2017, solar made 16% of California’s electricity.

    Think of it as part of a multi-pronged strategy to reduce emissions. Hopefully another prong of the strategy is investing in new ways to clean HC emissions – no problem with that.

    There are three problems with letting the market decide:
    A. Global warming is a long term problem. What company is going to hit their quarterly numbers investing in something that shareholders don’t care about today?
    B. China isn’t waiting – they are subsidizing solar very, very heavily. If we choose not to invest and compete, then we shouldn’t be surprised when America’s next generation energy companies are non-competitive.
    C. Global warming isn’t going to slow down on its own.

  41. Ocean Thermal Energy Conversion has been a technology I’ve found with a potential to change the world, and reverse this whole system. I agree with your points.

    Atlantis Shall Rise!

  42. Here’s a problem for wide-spread solar over the next century. The amount of solar energy falling on a sq meter of ground per hour is the limiting factor when compared to hydro carbons. Hydro carbons are effectively millions of years of solar concentration which have been baked and percolated into areas of the earths crust just waiting for us to use them. Our ability to extract said HCs is getting cheaper every year. We have trillions of dollars of infrastructure set up to extract, transport and consume HCs. HCs are convenient, portable, reliable and getting cleaner all the time. Unless we figure out a way to MASSIVELY reduce energy consumption, but retain the same work with less energy, magic, solar will not replace HCs, or HCs become scarce and costly. Land usage for panels etc create new problems. The sun goes down, clouds show up, rain, dirt and gunk happen. Inefficiency ensues, unless we dump $$$ into maintaining the panels. Effectively, solar panels are your green leaves collecting solar energy and converting it. IF, we get massive battery storage that’s economic, then it is the pool of concentrated sun light. However, said batteries are just getting a few hours light per day vs millions of years HCs represent. Eventually we will get there, but so far solar has been a massive waste of tax-payer dollars and investment. No subsides for solar or oil business should exist. Let the market decide.

  43. Brian, this sounds like good news, but I’m a bit confused. Please help me.
    Solar cells normally can convert about 15-20% of the sun’s energy under good conditions. Some better, some worse – and depending on conditions. Is this going to mean PLUS 10 to 25%, so the cells create 25-30 or 40-65% (best case)? Or should I read this 25% of 15-20% and get ~18-24% under good conditions?
    The other question I have is on life expectency. Will these (presumably) higher cost cells using fairly pure materials (99.99%+) have a better R.O.I., and will they last for more than a few years?
    Roofing materials like this and good batteries/storeage would go a long way in prepping for power outages, or remote weekend cabin power.

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