The Most Efficient and Accessible Solar Cell Yet

In the past solar cells are a source of clean energy had not been cheap or easily accessible. But now André Taylor, Associate Professor at New York University’s Tandon School of Engineering, joins Hari Sreenivasan to discuss how major steps toward a low cost efficient solar cell can be mass produced.

TRANSCRIPT

In the past, solar cells, a source of clean energy, have not been cheap or easily accessible.

But now André Taylor, associate professor at New York University's Tandon School of Engineering, has led a team of researchers who have made a major step toward a low-cost, efficient solar cell that can be mass-produced.

He joins us today to talk about his work.

So, first of all, the big picture -- what's so difficult about making a solar cell efficient and inexpensive?

So, one of the challenges with solar cells is the cost, and so people want to drive the cost down.

And, so, the majority of solar cells that are used in the industry now are silicon-based solar cells.

But silicon is very expensive.

So, it's a wafer-based process -- very, very expensive.

And that's a big barrier to doing wide-scale adoption of solar-cell technology.

This thin-film technology, which is perovskites, which represents the third generation of solar-cell technology.

It's very promising, because it can be made from very, very cheap materials and can be made for scalable nanomanufacturing technology techniques, such as roll-to-roll manufacturing.

What's roll-to-roll manufacturing mean?

Yeah, so, roll-to-roll manufacturing is if you have -- If you can imagine you have a flexible web that goes through various rollers, and it's a continuous process.

So if you can imagine a big roll, like if you're looking at, like, a roll of paper or something that goes through different chambers, then that's a roll-to-roll process.

So the solar film would be kind of pasted together?

Exactly. So, the solar film would go across a web.

It would go over these rollers.

You could add the different layers on top of the web, and then you have a full solar cell.

And then you could roll it up.

It's flexible.

And then, when you want to dispense it, you can dispense it across wide areas.

And you can't do that with silicon.

Instead of changing the process, you're talking about changing the components so that you can -- or what's being rolled together?

Yeah. So we're talking about -- This falls in the category of thin film, which is organic solar cells.

And organic solar cells have the possibility of being flexible.

And they also are made out of cheap materials.

Right.

And so that's an advantage that this has over silicon is -- it can be made very cheap.

So, if you look at this almost sandwich-like process of putting all these different layers together, what parts of the sandwich are you changing?

Yeah, so, the part that we're working on, in the perovskites -- so, there's lots of different layers, so it is a sandwich type of structure.

People work on the intrinsic layer, which is the perovskite crystal itself.

Some people work on the whole transport layer, and some people work on the electron transport layer and how to interface those layers in between.

My research group for this production -- we worked on the electron transport layer, which we use a spray-coating technique which is compatible to roll-to-roll processing.

So you sprayed the middle layer of this sandwich on it?

Yes. So, typically, on a research scale for perovskites, they use spin casting.

So you put it on a chuck and you spin-cast and you put your layers on.

But that's not necessarily compatible for scalable manufacturing for roll-to-roll.

So what we're showing here in this technique is -- by using a spray-cast technique, we can actually spray the electron transport layer and we can get a very good layer, which conducts electrons very effectively and gives a very good performance for perovskite solar cell.

So, what we're seeing are actually the outer layers of this, what I had in my hand.

You're talking about a layer that's in between, something that I can't actually physically see, correct?

Right, right.

So, this is one out of, I would say, maybe 3 or 4 layers that we're talking about.

So, how long do you think it is until there is parity between the existing process that we have today and the type of things that you're working on?

Yeah. So, I think it's gonna take a while.

There was a paper that was published maybe a few months ago, in the journal Joule, where they talked about there's a time lag.

So, they said between when you have a solar cell and the research scale and when it becomes commercially available, it's about 2.4 years.

And I think this is gonna take some time.

I think there's a lot of problems that come along with it.

So although the efficiencies of perovskites have been up to 22% or a little bit higher, the area size, the durability, all those things come into play.

So, for example, this solar-cell device here -- this is five devices on one device.

The active area is only 1.8 millimeters squared.

So that's very, very small.

So it's, you know, very, very different from a silicon panel, which is a large area.

So, first, you have to get the efficiencies up.

Once you get the efficiencies up, then you have to work on figuring out how to create a large-area solar cell.

And then once you can get the large areas maintaining good efficiency, then you have to work on the durability.

So there's a lot of different steps.

And when we're talking about durability, we're talking about silicon panels that have been proven for 20 to 30 years.

So when you buy a panel, then you want it to last for, you know, at least that amount of time.

And if you have a higher efficiency, then, of course, you get a faster payback from your investment into solar technology.

And it has to last, hopefully, the lifetime of your house, right?

Exactly. Yes.

André Taylor, NYU Tandon School of Engineering, thanks so much for joining us.

Thank you. Appreciate it.