Nanotechnology Expert Explains One Concept in 5 Levels of Difficulty

Hi, I'm George Tulevski, and I'm a research scientist

at IBM TJ Watson Research Center.

Today I've been challenged to teach one concept

in five levels of increasing complexity.

And my topic is nanotechnology.

Nanotechnology is a study of objects in the nanoscale

between 1 and 100 nanometers in size.

And it turns out that objects in this size scale

have really interesting properties

that differ from objects at a macroscopic scale.

Our task is nanotechnologists

is to understand these materials,

understand their properties,

and then try to build new technologies

based on these properties.

At the end of the day, my hope

is that you'll understand nanotechnology at some level.

Hi, are you Bella? Yes.

Bella, I'm George, nice to meet you.

Nice to meet you too! I'm a research scientist.

Do you like science? Yeah.

I wanted to talk to you about a specific type of science

called nanotechnology.

Have you ever heard of this word before?

Nhn nhn.

Nano is kind of a funny word, right?

It's a word that's used before another word,

and it means one billion.

What's the smallest object you can think of?

A baby ant? A baby ant?

Very good.

So I have over here a meter stick, let me show it to you.

And so that's a meter and if I divide it by 1000,

I get a millimeter. So milli just means 1000.

There's all these little lines on the ruler.

And each of those little lines is one millimeter.

So a baby ant is probably a couple of millimeters.

So even the thing, that's the smallest thing

you can think of, it's a million times bigger

than a nanometer.

Tiny, tiny, tiny. Tiny, tiny, tiny, tiny.

If I took this stick and I was to draw 1 billion lines,

the distance between those two lines would be one nanometer.

So that's really all it is. It's just a measure of size.

But it's really, really, really tiny,

smaller than anything that we can see with our eyes.

The reason why, in nanotechnology, scientists,

we care about things that are that small,

is because there are objects called atoms.

Have you ever heard of atoms before?

Yes.

I first heard of them

on a show I watched called StoryBots.

They're just little things

that make up everything on Earth, even earth.

That was a perfect explanation.

But what if I told you that scientists

invented a special type of microscope

that not only lets you see atoms,

but also lets you move them around

and build things with them.

Would you think that would be pretty cool?

Yeah!

So it's called a scanning tunneling microscope.

And not only can you see the atoms,

but you can move them around.

Atoms are kind of sticky.

You can actually build things using this instrument

with actual individual atoms.

So if I gave you that machine,

would you want to make something?

Would you want to look at something very carefully?

I would want to make a unicorn out of atoms.

You are definitely a second grader! [laughing]

My daughter would probably answer the exact same way.

A unicorn would be awesome.

Why do you study stuff so small?

I study it because objects that are that small

have really interesting properties.

They behave completely different than objects that are big.

And because of that,

we can build really cool things with them.

Like really fast computers, for example,

or new types of batteries or new types of solar cells.

And a lot of nanotechnology

is kind of like playing with Legos.

You take these small objects

and you put them together to build something new.

Something interesting that no one's built before.

It's like Legos for scientists.

Cool. [light music]

So how old are you? I'm 16.

16. So what is that, you're in 10th grade?

Junior year. So 11th grade. Have you of nanotechnology?

Have you heard of this term before?

Yeah, I've heard of it. What do you think of

when you think of nanotechnology?

It kind of seems very science fiction.

You know, you're right.

When you read about some of these technologies,

it does feel like science fiction.

But the part of nanotechnology

I wanted to talk to you about

is stuff that you probably use every day,

most of your day, all of the time.

Can you guess what aspect of nanotechnology

I'm gonna talk to you about? My phone?

Yeah, so modern computer chips

rely heavily on nanotechnology.

Does this look familiar to you?

Can you guess what this might be?

I don't know.

So this is a silicon wafer,

and they're embedded in basically almost every object

that you use, from a laptop, to a phone, to cars,

television sets, appliances.

We ended up cutting these into little squares

and those repeating patterns, each of those is a processor.

And those chips are what goes into all of these objects.

What I want to talk to you about is how we got

from where we started, and how we're able to actually fit

18 billion of these little devices

in a little one inch by one inch area.

They're called transistors. It's a switch.

Very simply, think of it as a light switch

that turns on and turns off using an electric field

by applying a voltage. OK.

I went through my kid's Lego bins

to build a very simple model of a transistor.

And these are wired together in circuits

so that you can do computation.

You can do logic with them.

Where nanotechnology comes into play,

the way you double the number of transistors on a chip.

Can you guess what you would have to do to this transistor?

You make it smaller?

You have to make it smaller. Exactly.

But here's the problem.

So about 10 to 15 years ago, the devices got so small

that if you shrunk them this gate,

that actually turns it on and off

loses its ability to control the channel.

And so what they did, was they took devices like this

into these things, we call them, FinFETs,

kind of like a fin on a fish.

So they're very thin transistors.

The width of these fins is only six nanometers. Okay?

So 6 nanometers is 25 to 30 atoms across.

And they repeat this

over the entire wafer just about perfectly.

It's just a huge feat in engineering.

But these types of devices are exactly the kind of devices

that your phones and computers either have,

or will have in the near future.

And it's a way that nanotechnology

is directly impacting you right now.

How do you make stuff that small?

Obviously it's not handmade, so is it factories and stuff?

Exactly.

So these are made using a technique called lithography.

You basically coat the silicon wafer with a polymer.

Then you put a mask on it

and then you shine light through it.

And the features of the mask, the size of those holes

determine the feature size in the chip.

It's not just the size of the mask that matters.

It's the wavelength of the light that's used.

We talked about nanotechnology being science fiction before,

but this is real stuff that's being produced,

that's being made, that's being used every day by people.

In middle school, I built all of the little switches

where you turn the electricity on,

and it goes from one thing to the other.

But those are the really big, comical,

like plugging in Legos and stuff.

When we saw the picture of all of the little ones,

it's like a city, it's crazy how simple

and complex it is at the same time.

Exactly. I couldn't put it any better. That's right.

[light music]

So what's your major? Chemical engineering.

What made you choose that? Like any freshman,

going into chemical engineering,

I was like, I like chemistry!

So I'm gonna go into chemical engineering.

But luckily I also like

all the math and all the science too.

So have you taken a quantum mechanics course?

I have. I took that last year.

I think to really get deep into nanomaterials

and nanoscale devices, you really have to understand

to some level, quantum mechanics.

What it teaches us

as we make these devices smaller and smaller,

their properties begin to now depend

on the size and the orientation of these devices.

There are materials, and you're taking a 2D materials class,

you know about this, that are intrinsically thin.

As they're grown, as they're fabricated,

they're already at the nanoscale and they possess

these quantum confinement properties

that as a nanotechnologist, you try to exploit.

And so the first ones I wanted to talk to you about

are quantum dots, have you heard of quantum dots before?

Yes. So these are

typically semiconductors.

They can be cadmium selenide cadmium sulfide, zinc selenide

and they're small clusters of atoms.

They can be from 2 to 10 nanometers.

What's interesting about these materials?

Well, the other day we were talking about

the different dimensions you can have of nanotechnology.

So all the way from like 0D to 3D.

If I remember correctly, my professor labeled it as 0D?

That's correct. Yeah.

Because of quantum confinement,

once you get below this 15 nanometer range,

the band gap of the material

depends completely on the size of the material.

So in bulk materials, if you want to change the band gap,

you have to change the material, right?

But in these quantum dots specifically,

just by changing the size, you can change their band gap.

And because their band gap is changing,

their optical properties are different.

And you can precisely tune the wavelength of light

that they emit just by changing their size.

What are the applications of these quantum dots?

There are people that are exploring

using these materials for diode lasers.

There are companies that are building displays

from these materials.

And there're even people thinking about

if I take these quantum dots,

and I change the chemistry on the outside

so they stick to specific types of cells or tissue,

that I could really do some interesting imaging

and therapeutic work to track disease,

even maybe to treat disease,

if you can very precisely control the chemistry.

How far away is this

from being actually used on an industrial level?

The optical applications are in development.

The science has really been worked out.

The health stuff, because of all of the things

you have to consider when you're putting something

in someone's body is definitely further out there.

For example, some of them are made from cadmium.

Cadmium's toxic.

You would never put that in someone's body.

But there are other materials like gold and silver

and titanium dioxide, which are less toxic

and people are exploring using those.

So have you learned about graphene?

Yeah. Do you know what this is?

Carbon nanotube? Carbon nanotube, right.

So if you roll up graphene, depending on how you roll it

and the angle, you roll it with,

it has different properties.

So if I roll it one way, it'll act like a metal.

If I roll it a different way,

it'll act like a semiconductor.

The one that gets everyone most excited

is that the electrons and holes

move very fast through graphene.

And so there's a lot of interest in using these

for certain types of high-speed electronics.

The other interesting application

is because it's one atom thin,

it's very sensitive to changes in the environment.

And so there's a lot of interest

in using them as diagnostics.

It's on us researchers to find ways

to A, control that process and then B, to actually build

some sort of interesting technology from them.

So you've been talking about

the different ways you can say, roll these nanotubes.

So how do you go about building

and controlling these nanotubes in terms of their diameter?

You're speaking my language.

This is what I spent many years of my life working on.

You don't physically roll up graphene.

You grow nanotubes by basically taking nanocrystals

and you deposit them on a surface.

And then you do a CVD process, chemical vapor deposition.

So you basically flow in a carbon source,

the carbon dissolves in a nanocrystal

and then once nanocrystal is saturated,

the nanotubes precipitate out of them in tubes.

Then you have to develop ways

to go into this pile of nanotubes

and pull out exactly the ones that you want.

So I have to find ways to program them

to go exactly in the places that I want.

I modify the surface of the nanotube with specific molecules

that recognize one type of surface over another.

And then I just pattern the surface and the tubes just land

exactly where we want them to.

And it's still very much in the research stage.

The ultimate goal is to build functional

high-speed electronics using these new materials.

In my nanomaterials class,

actually just a couple of days ago,

we were talking about different applications

of nanotechnology and things we know.

And we touched on the topic that right now,

silicon is down to the smallest level that it can get.

And so we have scientists out there

researching other materials, to replace silicon.

Yeah. 100%. That's right.

And that's the motivation

for looking at these emerging materials.

But I would never bet against the innovation

and the creativity in this nano electronic space.

Tens of thousands of scientists,

every time they hit a barrier, at least historically,

as a guide, they have found a way to overcome it.

It's a real marvel in ingenuity.

I gotta ask.

The lights that are behind you, is that related

to the quantum dots that you work with at all?

It's just pretty lights. [laughing]

But now that you suggested it, these were inspired

by the array of quantum dots that we showed earlier.

So that's the story I'm going to stick with.

[laughing] I like it.

Well, thank you so much. This was all so very interesting.

[light music]

So you're a graduate student.

And so tell me a bit about your work.

I've been working on energy storage materials.

And the most popular are batteries that we work on.

A lot of the revolution that's come in electronics

is kind of our model

to try and use some nanoscale advances

and put them into batteries.

What is it about nanomaterials, that scale

and the properties of these materials

that make them uniquely promising

to incorporate into battery technology?

So for batteries, one of the main constraints

when we're designing batteries is trying to maintain

or reduce the volume and mass of the components.

And nanomaterials are particularly well suited

to adding functionality

while having this negligible increase in volume.

So we get a huge benefit from using nano materials

without sacrificing the volume of the battery.

What is it exactly that you're trying to tease

out of these materials to improve the battery's performance?

At first, one of the main things that we did

was use nanomaterials to add conductivity.

And so carbon anodes and graphene are really good

at adding conductivity to batteries.

And then in the subsequent years,

nanomaterials have been really interesting

from things like incorporating sensors into batteries,

to increasing the functionality of batteries,

having some responsive materials

that use things like graphene sheets

that are incorporated into a matrix,

and then you add a safety functionality to a battery.

We're trying to squeeze out

almost all the functionality that we can.

And as new nano materials are being discovered

and there're new properties being discovered,

a lot of the time that someone tries to think of a way

to translate that into a battery.

Because the materials are so small,

they're at the nanoscale,

their properties are dominated by quantum mechanics,

which means that even slight changes in their size,

in their orientation

give profound changes in their properties.

And while that's very scientifically interesting,

and it allows you to tune their properties

by making subtle changes, from a technology point of view,

it's a bit of a headache in the sense

that in technology want to optimize for a property

and then repeat that over and over again.

So what are some of the challenges that you face in the lab

related to working with these materials

and then trying to incorporate them into the batteries?

I think every step of a process in a battery

is something where you have to think about

how would this translate to making a battery

in terms of the production?

One thing that I think is very interesting

about the field of nanoscale materials in general,

is that how you make the material

changes the properties a lot.

And so we claim that this 2D material has this property,

then tying that to the battery performance

is something that's pretty difficult to do.

It takes a few steps in between.

So we have to think kind of creatively

with how we can do that.

That's actually, I think a very common problem.

We can build a device in the lab

it could be a transistor, can be a battery.

And then you ask the question,

okay, so what's the next step?

How do we take it from that lab demonstration

into a technology?

The kind of work that I'm very interested in

is developing tools

to make the exact type of materials that you want.

The tools that we've used in the past

for conventional fabrication

just don't work with these materials

because they're all grown from the bottom up.

They're intrinsically small, and you have to find ways

to either use chemistry or some other means

to get them to assemble into the structures that you want

to actually either grow specifically what you want

or after you grow them, to pull out the ones that you want.

You need to be able to build that same thing

over and over again, with the exact same properties.

No one institution, no one research lab, no one national lab

is gonna solve all of these problems on their own

because they are difficult problems.

And there is a real important payoff at the end.

And it's gonna take all of us, making our contributions

to push this field forward. [light music]

I remember reading your papers when I was a student

and we're all trying to create these materials

and finding ways to exploit their properties.

What I love, and I'm delighted that you're here

to talk to us about is how you took inspiration from nature

and sort of recognize that nature's figured out a way

to both synthesize incredibly complex nanostructures

with high functionality and how you sort of were inspired

by that to do the research that you're doing now.

Life gave us this toolkit

that is already on the nanoscale.

So we think that that's a great place

to think about making materials on the nano scale

and manipulating materials on the nano scale,

and wiring them together as well.

This abalone shell, you can see

the exquisite beautiful colors and structures of it.

This is a nano composite material.

If you take this and fracture it, and you look at it

in a scanning electron microscope, what you'll see

is that it's made out of these beautiful tablets.

And I studied that as a graduate student.

I looked at that and I said, that is completely amazing.

You have an organism in the ocean,

that takes what's in its environment,

which is calcium and carbonate.

That's dissolved in the water and templates it

into this really exquisite structure.

And so you think that's great.

Calcium carbonate is great,

but what if we wanted to make a solar cell

or a another electronic device or a battery,

how would you get an organism to do that?

And you say, okay, that's a really crazy idea.

But is it really that crazy if this abalone,

already figured out how to do it, 500 million years ago?

So we're saying, okay, abalones build shells.

Can viruses build solar cells, can viruses build catalysts?

Can they build batteries using the same kind of idea?

It's really fascinating work,

especially now we're all familiar

with the viruses and how they act.

And I'm not aware of any viruses that build nanostructures.

So how did you come to that?

And then how do you actually program a virus

to do your bidding? We work on something

called bacteriophages, it's a virus with DNA.

This particular bacteriophage called M13 bacteriophage

is made up of single stranded DNA and proteins.

It's long and thin.

So it's 880 nanometers in length,

and it's about 9 nanometers in diameter.

And so one of the reasons I love it

is it spans the nanoscale

and almost the micron scale at the same time.

Take the single strand DNAs, obviously a model,

and you can cut it with molecular scissors.

And you can put a new piece of DNA in between.

And so you put a small piece of DNA in there

that doesn't belong there.

And that piece of DNA

is going to randomly code for a protein.

Now, the next time that that virus is replicated

within a bacterial host,

it'll be able to put a new protein sequence on the coat,

just a short protein sequence on the coat,

maybe like 8 or 12 amino acids in length.

And just like that abalone is going to grab calcium

and build calcium carbonate.

We're going to have our viruses build iron phosphate

for a battery electrode material

or Gallium arsenide or cad sulfide

for a semiconductor material.

So you've evolved, and I suppose, trained these viruses

to build the materials that you want them to build

by exposing them to the raw materials

and then evolving their function.

We're talking about the electronics from nanomaterials.

That critical issue that we're facing

is how do you go from those single experiments

with a single material, understanding its properties,

how do you scale that to the billions of devices

that you need in a technology?

It is a chemistry driven approach.

We're not going to grow them exactly where we want them,

but to take that one step,

and to tie into what you're doing,

tt sounds like there could be an area of collaboration

where instead of using conventional chemistry,

that we can train some of these biological elements

to do that work work for us.

Biology is chemistry.

Molecules, proteins,

and DNA work with all the same kinds of bonding

and things that the chemicals

that you're gonna be looking for in these processes.

It's put together in a way

that when a protein or enzyme folds,

it almost always folds correctly.

That's kind of the beauty of it,

the predictable aspect of it encoded in its DNA.

If we need to make it the same over and over again,

then as long as you have the right DNA sequence,

DNA is a beautiful structure on the nanoscale.

And there's really, really cool, incredible work

on DNA origami, when DNA can fold

into just the right structure.

And so I can see that as an interface,

that would be really cool and interesting in your work.

And you can have the virus make the DNA for the DNA origami,

and then you use DNA to assemble your beautiful structures.

It's really fascinating.

You have all these little worker viruses

building the materials for you.

How are you then applying these materials

that you're building?

We started thinking about

how can we make an impact in cancer?

We do it mostly in imaging technology

to look deep inside the body noninvasively with light.

And the way that we came about that

was through solar cells and batteries.

We trained our viruses to pick up carbon nanotubes

and hold onto them very, very tightly.

And then we'll give a virus a second gene,

decode for a protein, to grow, in a case of a battery,

a battery electrode material.

It allows it to weave together a good electrical conductor

and a good ionic conductor at the same time,

all within this really, really small space.

And the optical properties of these carbon nanotubes

are in the wavelength.

That is interesting for imaging deep inside the body.

We started building a bunch of imaging tools

that could image above a thousand nanometers, a wave length.

And so this is in [audio distorting]

and that's a really special window

where you have some optical transparency

of tissue in the body.

The other gene, we engineered to find ovarian cancer.

We developed imaging tools with Harvard Medical School

and MIT Lincoln Labs to find tiny ovarian tumors.

It's hard to see things less than a centimeter in size

with ovarian cancer, just based on the location in the body.

But with our imaging system, we could find tumors

that were below a millimeter in size, actually.

Looking ahead, 5 years, 10 years,

where do you see your own work,

and maybe the field more broadly?

The future I'd like to see

is environmentally friendly chemistry

and materials synthesis.

And I think that we're really going that way.

If we think about batteries of the future,

solar cells of the future,

thinking about earth abundant materials and processes

that are compatible with the earth and environment.

One of the things I love about about nanoscience

is it tends to break up the silos

between those traditional scientific disciplines.

My training was in chemistry,

but I had to very quickly merged chemistry and physics.

And now I see an area where chemistry, physics,

and biology are coming together to produce new materials

and new technology, and to advance the field forward.

And so being in this field,

you kind of have to cross pollinate

between these different disciplines

and kind of advance the field together.

I agree completely. We like to solve problems.

Nano bio is the toolkit that we bring a lot.

It happens to be a very strong and evolving toolkit.

That's another thing that I love about biology

is if you can come up with a solution

that's not perfect at all to begin with

when you're making a battery electrode material

or any kind of material you're making,

you have evolution on your side

to try to make it better and better as a function of time.

That can be quite rapid. So Angela,

thank you so much for joining us.

And I look forward to seeing more work

coming out of your lab in the future.

Thanks for having me, George,

it was really fun to interact, and I'm very excited

about our future collaborations.

Me too. Absolutely. [light music]

I really enjoy talking to these five different people

about nanotechnology.

Nanotechnology is a field that affects all of us every day

as finds its way into a variety of applications.

And I hope you enjoyed it as well and see the impact

that nanotechnology has on your life today,

and how much more of an impact it'll have

on all of our lives in the future.