How Much Better Can Solar Get? Deep Dive Australia 08: Martin Green

So now let's come back to you said that there were innovations of the '80s and '90s, um, uh, that are now in 90% of all the cells being manufactured.

So first of all, what were the innovations? And the second question is gonna be, what took them, what took you so long for them to become so widespread?

Yeah.

Well, when I, when I started my PhD, um, you know, there's a, a process called quantum mechanical tunneling, and it's not digging tunnels [laughs] like Elon's interested in, but it's, uh, to do with electronics.

But y- you know, the quantum mechanics showed that electrons could go through barriers that traditionally they weren't allowed to go through.

Um, and, um, Nobel Prize in, oh, '71 or '73 was awarded to, uh, three researchers that had been working on tunneling.

So it was quite a hot topic in that era.

So my PhD was to look at the, the, the properties of a s- specific tunneling structure and, um, uh, it turned out that it's very useful in photovoltaics and is now used in 90% of the solar panels that are being used, but it dates right back to then.

So, um, when, when we first started our work at the University of New South Wales, NASA had just started a program to try and improve the efficiency of silicon space cells, and they figured, you know, everyone had done pretty well with the voltage.

This is in 1974.

There'd just been a big jump in the, in the ability to get current out of the cell by doing things like texturing the top surface of the cell to reduce reflection and a few little tricks like that.

So NASA realized that we needed to look at improving the voltage output of the cell 'cause it was a lot less than what, you know, calculation showed was should be technically feasible.

And these tunneling structures that I worked on for my PhD Actually solved that problem of getting a high voltage from the cell very effectively.

So NASA had a lot of contracts.

We weren't init- contractors.

We weren't initially one of them, but, you know, they had Motorola and, you know, they're doing work in their own labs.

They had about 10 contractors working on improving this voltage and in our then very primitive lab at the University of New South Wales, we managed to beat them all.

And declare victory.

And declare victory.

Exactly.

So we were creaming all these, um, NASA contractors and so, um, that brought our work to international attention just through our ability to do that.

And is that then...

When you s- you talked about the innovations that are now in every cell, was that, was that that or was that what happened next? Because you've, you've, you then, you, you entered a period at some point where you won the efficiency, the cell efficiency kind of, um, world record for, I don't know how many years it was, 25 years in a row, something like that?

Yeah.

Yes, no.