2024 Perovskite Breakthroughs are the Future of Solar

Perovskites are often hailed as the next  big thing for solar panels. They’re more  

efficient than silicon photovoltaics (PVs) could  ever be, and they have higher yields. However,  

their fragility and short lifespans  have relegated them to the lab...so far.

But 2024 is looking to be the year of  the perovskite. The last few months  

have seen new perovskite researchers  all over the world smashing records,  

including durability. Because of this, some  of these new perovskites are even set to hit  

the market this year. Let’s check out some of the  most exciting breakthroughs in the field and see  

for ourselves if perovskites are finally ready  for their big debut. And why should you care?

I’m Matt Ferrell … welcome to Undecided. 

This video is brought to you by  Opera, but more on that later.

It truly feels like we’re at the beginning of a  massive paradigm shift for solar. Researchers are  

breaking so many different perovskite records  using such widely varied techniques within the  

last few months, it’s mind blowing. Some teams  are coming at this from a chemistry angle,  

trying to engineer tougher perovskites.  Others are looking at the very architecture  

of a perovskite PV cell, experimenting with  under-studied cell blueprints and achieving  

surprising results. Then there’s those who are  having those random “eureka” moments that make  

for great science stories, when making one  little change causes everything to fall into  

place. There's just so many wild advances all  happening at once. With so many discoveries,  

it stands to reason that there’s hope for  at least some of them to reach the market.

Let’s back up first, though. What are perovskites?  We’ve talked about them before on the channel,  

so here’s a quick TL;DR. They’re a family of  crystalline materials with the same crystal  

structure as calcium titanate. Current  silicon solar cells only capture around  

20% of usable sunlight, meaning we’re leaving  about 80% on the table. Perovskites have the  

potential to use more of that sunlight,  and many easily break that 20% figure;  

they might be able to break silicon’s  theoretical maximum efficiency of 29%.

Better yet, they can be “tuned” to capture  light from parts of the spectrum that silicon  

PVs can’t touch. This is good on its own  merits, and it also allows you to Voltron  

perovskite and silicon layers together to form  “tandem” cells that capture much more light  

than either could on their own while sharing the  same footprint. To sweeten the deal even further,  

perovskites are also relatively  easy to synthesize and produce.

To give you an idea of just how big of a  deal increasing solar panel efficiency is,  

we can take a look at my own home as a point  of comparison. I have REC 400 Watt panels on  

my house, which have a rated efficiency of  about 21.6%. With four hours of sun a day,  

a single REC 400 panel would generate about 576  kWh/year. These are high level calculations and  

don’t take local conditions, inverter hardware,  etc. into account. Upping that efficiency  

(with the same exact single panel footprint) to  something like 25% may not sound like a big jump,  

but would produce about 682 kWh/year. That’s  a 15% jump in output overall. That would mean  

instead of needing something like 30 REC panels  to achieve my energy goals at 21.6% efficiency,  

I’d only need 25 panels at 25% efficiency.

So what’s the catch? Cost is usually the issue  with these sorts of things, but not here. Believe  

it or not, perovskites aren’t prohibitively  expensive. In fact, easy manufacturing  

techniques and widely available materials mean  perovskites can be cheaper than silicon PVs.  

That means that in my hypothetical example, I  would not only need fewer panels to achieve my  

goals — they’d theoretically be cheaper per panel,  too. No, the real issue is their durability.

While they’ve performed very well in lab  conditions, perovskite cells degrade very

quickly out in the real world. Some can see a  capacity dip as large as 80% in two years or less.  

Compare that to my REC 400 panels with a 25 year  warranty that guarantees only about an 8% dip by  

the end of the warranty. What’s killing perovskite  cells so fast? Heat, moisture, oxygen, and even UV  

rays…y’know, all the things that a solar panel  is going to have to face day in and day out.

We can’t slather our solar panels in a  nice coat of sunscreen, so the benefits  

we mentioned a minute ago are effectively  locked behind the durability problem. And  

that’s why finding a solution to it has become  something like the holy grail of solar tech.  

That brings us to the big question: has anyone  made any progress solving this problem, or are  

perovskites a dead end? And if they are, what  other pathways are there to solar advancement?

Well, good news. The UK-based company  Oxford PV returns to this channel yet  

again. And this time, they’ve solved the  perovskite durability issue! So what do  

you think? Jump in the comments and let  me… no, no I’m kidding, don’t click off!

Now, it is true that Chris Case, Oxford PV’s  Chief Technology Officer, told the Wall Street  

Journal that the company’s cells are designed to  meet or beat a 25-year life span. Oxford PV says  

it’s proved this by studying full-size modules  in outdoor environments for over three years,  

then used that data to predict long-term  stability. These studies also show that  

its best tandem cells lose only about  1% efficiency in their first year of  

operation and have a very small rate of decline  thereafter. Frustratingly, these results have  

yet to be published, though this could be for  proprietary reasons. After all, if you’re the  

only one who cracked the tough perovskite code,  well, there’s going to be a lot of value in that.

That said, Oxford PV is making definite progress.  It’s teamed up with the Fraunhofer Institute for  

Solar Energy Systems (FISES) in Germany, which  recently used Oxford PV’s tandem cells to  

construct a working solar module. FISES just  announced that this module achieved a record  

breaking 25% conversion efficiency. Remember what  that could mean based on my calculations earlier:  

about a 15% increase in power output over a year.  Now that the efficiency is confirmed, FISES and  

Oxford PV are working towards certifying that  all-important longevity stat. To this end, they’re  

putting the module through a battery of intensive  long-term stability tests. And while it pays to be  

skeptical about these sort of breakthroughs,  I should note that Oxford PV’s factory in  

Brandenburg, Germany, is set to begin commercial  production of their tandem solar cells later  

this year. So, if all goes according to plan, we  won’t have to wait long to put them to the test.

They aren’t the only group with interesting  progress, but before we get into those it can get  

a little overwhelming as my team and I research  these topics. There’s so much news and research  

to sift through that I get lost in my browser  tabs ... a lot. Well, today’s sponsor, Opera,  

has been a huge help with this. I really love  using Workspaces to keep personal tabs separate  

from work tabs when pulling together research.  It’s really easy to flip back and forth between  

those groups. I’ve also really been loving tab  islands, which automatically consolidates related  

tabs together into groups. This one was kind  of an eye opener for me. For instance, as I was  

diving between articles on different perovskite  advancements, Opera automatically keeps those  

tabs together in an island. I don’t know about  you, but I often get lost in a sea of tabs and  

this really helps me out. I also really like the  sidebar, which keeps things like my social media  

accounts one quick click away in a nice slide out  window, but the thing I’ve found myself using a  

lot in the sidebar is Aria. Sometimes I come  across a paper in another language and can quickly  

translate a section of that article with the help  of Aria. Or ask for a quick summary of an article  

to see if I’m heading down the right path quickly.  And finally, I love how easy it is to screen  

capture a section of a webpage or article, or even  a full webpage image for use in a Notion ticket  

for my team to reference later. Opera really  has helped me streamline some of my workflow.  

If you’d like to try out Opera for yourself check  out the link in the description. Thanks to Opera,  

for supporting the channel. And thanks to all  of you, as well as my patrons, who get early,  

ad-free versions of my videos. So back to who  else is making good progress in perovskites.

In other developments, an international  group of scientists led by the King Abdullah  

University of Science and Technology  (KAUST) in Saudi Arabia are taking a  

different approach to perovskites. Rather  than focusing on making better materials,  

they’re optimizing how we assemble those materials  for maximum energy generation and efficiency.

You see, one of the main limiters of solar  cell efficiency is the mobility of its charge  

carriers. Charge carriers are the electrons  and “holes” knocked free from their homes  

inside the cell by incoming solar energy.  The movement of electrons is, by definition,  

electrical current. “Holes” are places where  an electron could go, so their “movement” is  

really the movement of electrons as well. It's  actually these charge carriers that we use to  

create the flow of electricity, not the sunlight  itself. That's an oversimplification in the  

interest of time, so if you want to know more  check out some of my other solar panel videos.

Anyway, part of what makes perovskites so  efficient is that they allow those charge  

carriers more mobility than they get in a silicon  cell. Even still, the majority of these carriers  

are usually “captured” by the material they’re  conducting through, or defects within the cell,  

long before they can reach the electrodes  to be used as electricity. Not great.

This has led some engineers to add an extra  layer to the cells to help facilitate the  

capture of those charge carriers. Solar cells  have a P-layer (home of holes) or the N-layer  

(home of electrons). The light capturing  “I-layer” of perovskite sits between the  

two layers. This gives us two possible  types of architecture depending on which  

layer you want the sunlight to touch first: the  hole-layer (P-I-N) or the electron-layer (N-I-P).

Each architectural style has its strengths and  weaknesses, and explaining them all could be its  

own video. To keep it brief, the electron-first  N-I-P style is physically easier to construct,  

which means it's more common and better-studied.  It also helps that most of the efficiency records  

are currently held by team N-I-P. But recent  research suggests that P-I-N variants are much  

more durable than their counterparts, and  some can even match the N-I-P’s efficiency.

This is where the Saudi researchers are making  progress. They’ve developed a novel P-I-N setup  

with enhanced ligands, that’s the stuff that  bonds the perovskite to the other layers. It  

also acts as a kind of capstone or varnish on  top of the perovskite layer to protect them.  

The result is a perovskite P-I-N cell with a very  good power conversion efficiency of 25.63%. After  

1,000 hours of testing in 85 C (about 185  F) temperatures, they only degraded by 5%.

In yet another recent efficiency and  durability breakthrough, a team led  

by scientists from the Korea Institute of  Energy Research (KIER) have broken records  

for semi-transparent perovskite PVs. They  focused on semi-transparent perovskite cells,  

because they show a lot of promise when  used in windows and bifacial PVs. Why?

A solar cell requires electrodes. For mechanical  reasons, these electrode layers are best  

positioned as the outer part of the cells. It’s  like the bread of our solar sandwich. Of course,  

electrodes aren’t perfectly invisible, so they  tend to block some of the light. As a result,  

they tend to only end up on one side of the  cell. But what if we could make transparent  

electrodes? Well…we can. They’ve already been  around for years. So why aren’t all PVs equipped  

with transparent electrodes? Why aren’t all our  windows doubling as perovskite cells right now?

Here’s the thing: transparent electrodes cause  PV cells to degrade much faster because they  

don’t screen out high-energy particles that damage  the hole-transportation-slash-N-layer — all that  

stuff we talked about earlier. KIER scientists  fixed it by adding a metal oxide layer to screen  

out those particles and they found… even more  efficiency and fewer degradation issues?!

The Energy AI and Computational Science wing  of the KIER team took a look at the data  

and discovered that the N-layer was reacting  unexpectedly with the metal oxide. Normally,  

lithium is added to an N-layer to make it more  conductive and improve efficiency. Turns out  

the lithium ions were diffusing into that metal  oxide blocker and making them both less effective.

However, the KIER scientists found a pretty  elegant solution. Lithium ions already oxidize  

into lithium oxide. Previously, the lithium oxide  was assumed to be a harmless byproduct of this  

process. The KIER team deliberately converted the  flighty lithium ions into stable lithium oxide,  

and voila, enhanced durability and  efficiency. Their semi-transparent  

solar cells hit an efficiency of 21.68%,  making them the most efficient among the  

transparent perovskites electrodes in the  world. Better yet, they retained 99% of  

their initial efficiency after 240 hours  of operation, and their stability rating  

remained at 99% for 400 hours. If you’re  curious about transparent solar cells,  

I’ve got a video that does a deeper dive on  them that I’ll link to in the description.

But it’s not all good news. We need to talk…about  CubicPV. The company is backed by Bill Gates,  

and given his greentech investing record,  it’s up to you if that's a good thing or  

not. Just days after my 2023 solar  panel update video was released,  

CubicPV announced that, thanks to incentives  in the Inflation Reduction Act (IRA),  

it was going to build a 10 GW conventional  mono wafer factory. This was set to fill  

a supply chain gap here in North America and  create an estimated 1,500 green energy jobs.

Awesome. So what’s the bad news? Well, CubicPV  recently announced that it’s shifting to tandem  

perovskite cells instead, abandoning the wafer  factory in the process. Think about that:  

A major company ran the numbers and was so  confident that perovskite tandem cells were  

the future that it abandoned its silicon  wafer plans mid-stream. Surely a promising  

sign for the future of perovskites, but definitely not great for the community  

that was looking forward to the previous  promise of a bunch of good, green jobs.

Another thing about CubicPV: it’s claiming  to have tackled perovskites durability  

issues through “better chemistry” and  by “building intrinsic stability into  

the material itself.” There’s no further data  on how the company is planning on doing this,  

which doesn’t make me very confident. Given  that they’re working on a proprietary method  

to manufacture a lot of perovskite cells in  a fast, cheap, and energy efficient manner,  

it is possible that CubicPV’s perovskite  chemistry is proprietary too. Great if  

it ever comes to fruition, but again, I remain  skeptical until I see some hard evidence.

So, perovskites remain the solar MacGuffin, but  it does feel like we’re making real progress  

here. If just one of these companies  has truly solved the durability issue,  

we could be on the cusp of a solar revolution.  The market certainly seems to think we're on our  

way. The global perovskite solar cell  market size was just $94.8 million in  

2022. It’s expected to balloon to around  $2.479 billion by 2032. Even if these  

predictions are wrong and they’re not the  next technological leap in the solar sphere,  

their efficiency ratings are so impressive,  they’ll probably find their niche no matter what.

But what do you think? Do you think perovskites  are going to live up to the hype? Would you  

want them? Jump into the comments and let  me know. Before I go, I’d like to welcome  

new Supporter+ patron David Fain. Thanks so much  for your support. I’ll see you in the next one.