20 - Light Voices #7 – Raphael Pesch

00:00:03: Welcome to Licht hören, a podcast about light lighting and the people behind it.

00:00:09: Here

00:00:10: we explore this fascinating field from education in daily practice To how we imagine and shape its future.

00:00:19: Hi Raphael I'm very pleased to have you here.

00:00:21: You're working in Germany And do research on How We can use sunlight more efficiently.

00:00:28: But first Raphael Who are you?

00:00:31: What Do you do?

00:00:32: I'm Raphael Pech, i am a third year PhD student at Karlsruhe Institute of Technology and i'm doing research in the laboratory to investigate new solar cells.

00:00:42: What do you mean by New Solar Cells?

00:00:44: We have nice solar cells.

00:00:45: they are silicone and they're perfect or are there not?

00:00:50: Yes!

00:00:51: They are somehow perfect but they have limitations.

00:00:55: so we investigate new material –not just silicon-but it's called perovskite another crystal structure And with that new material on top of silicon, so applied to a silicon solar cell.

00:01:08: We can even get higher efficiencies and That is the main goal of our research.

00:01:13: Okay So you basically put something On top off something which is already working but Not not working good enough then making it better.

00:01:22: What is perovskite like what?

00:01:25: Can I have in mind when you talk about perovskyte?

00:01:29: Perovskytes are materials system easily tuned also in the laboratory and can make the light absorption for a different kind of the light spectra really efficient.

00:01:41: I see!

00:01:42: And you call this combination, all the solar cell and the perovskite on top?

00:01:47: You called that Tannin

00:01:48: cells?!

00:01:49: What we also do –and it is actually the main goal–is to put both together.

00:01:53: so when we use the silicon-solar cell then on top of the silicon solar cell fabricate the perovskyte's solar cell.

00:02:00: We can basically catch some parts of the light, in this case for example, for silicon.

00:02:05: The more reddish light and for the perovskite a more blueish light way more efficiently And then get more current out there More power all day.

00:02:14: So you'll catch more off the rainbow off the light with this combination?

00:02:18: Yes or In other words we catch the rainbow more efficiently.

00:02:22: You

00:02:22: work with daylight Basically although your engineer How did end up lighting How to use light?

00:02:31: really working in the field of light and like technology came down when I decided to study something To understand light, which my case was electrical engineering And Stan ended up special specializing more and more on that subject Finally also working in a car company In the subject of head lamps or headlights and real lights.

00:02:52: Then really using light to illuminate something and discover or see, for example the street.

00:03:00: And within electrical engineering.

00:03:01: there are millions of subjects that you can do... ...and I thought electrical engineering is quite well suited because i knew it has also something to do with this micro- and nano world.

00:03:12: This what you need to learn when you want to learn how light is generated.

00:03:17: And from that subject, then I specialized more and more.

00:03:20: the long guy was into my bachelor studies example light technology and light engineering.

00:03:26: That basically ends up on the other side of light which is the macroscopic world not thinking about how the light generated but rather how i can use it or project onto something.

00:03:38: This is what's interesting for car companies like Porsche because they need to illuminate the street, but also want to have cool designs for example in their rear lamps.

00:03:47: To have a great red color for the real lamp and this is what I did with my internship at Porsche later on as well when in the bachelor t-shirts that i did there.

00:03:57: Nice!

00:03:58: But how do you end up in Solar Salsa?

00:04:00: You work with a startup didn't

00:04:02: you?!

00:04:03: Yes so... When i started my master's i decided for specializing more into that, let's say micro nano world again.

00:04:11: And I had special specialization micro nano optoelectronics.

00:04:15: as you also worked in the US set right?

00:04:19: I decided during my master studies to not just see it at university but also two have a look on an industry or in startup back then which focused on photovoltaics and most specifically the incorporation of light into this solar cell by applying anti reflection coating.

00:04:36: And the cool thing, how they did it was actually... They just copied the structure that they found in nature more specifically on a rose petal and used to absorb light more efficiently.

00:04:49: Finally when working there I also got to know this field of bio-inspired photonic engineering which led me into the master thesis that i finally did in the US.

00:04:59: Was something special about your career?

00:05:04: which hooked you like something, oh my god.

00:05:07: Oh what a crazy moment was!

00:05:09: A lot of crazy and cool ideas that come up for interacting with light are actually already out there in the nature For example butterfly wings or rose petals.

00:05:20: They have phenomenon properties regarding transformation light absorption And we can just analyze them.

00:05:29: How

00:05:29: do you work daily with nano-level solar cells?

00:05:34: The solar cells that we fabricate, what makes them so special is they are really small.

00:05:39: So the thickness of the solar cell itself is just hundreds of nanometers which is way smaller than hair thickest Which also means when you make these solar cells We need to take care not destroy them while fabricating And destroying.

00:05:56: even a dust corn destroys it.

00:05:58: So whenever I fabricate the solar cells, either a synth film lab or clean room where we have conditions when no dust is around.

00:06:07: We dress up completely in a suit that prevents all particles from us floating into air and we are filters on it with which we can make sure to not destroy them immediately.

00:06:23: You print them with an inkjet printer in a full body suit.

00:06:28: Totally clean, it sounds paradoxical.

00:06:30: It's exactly the right picture you got!

00:06:33: The perosketzula cells itself have to benefit that they can be processed out of liquid phase.

00:06:38: so we use a solvent to solve all of the material necessary for these materials and then just put the solvents on glass sheet let all the solvent evaporate or dry out on a hot plate.

00:06:51: And then what remains is the material that's necessary for the solar cell, but when we go over to industrialization it needs to be square meter-sized so that can end up in a roof and one way to do this is inkjet printing.

00:07:04: actually

00:07:05: I'm really fascinated how big this lighting field like its not just putting light bulbs at the ceiling Or planning windows.

00:07:13: How does typical work day say nine two five four you eight four looked like.

00:07:20: And one typical day could be either I'm the whole time in lab, another typical.

00:07:26: they could be a kind of investigate what i did then the lap and look at results and try to sum it up write a paper about it.

00:07:34: Another Day Could Be I Have To Do Teaching So Im Just In Front Of A Class Of Students And Lecturing or even more crazy.

00:07:42: We go for conferences quite often, so we travel the world and then try to explain what we discovered...

00:07:48: When can I buy your solar cells?

00:07:52: So first of all silicon is great!

00:07:54: What we are doing is basically trying put the perovskite on top of the silicon to make it more efficient but the stability and scalability remain challenging And I'm, for example working on the scalability.

00:08:05: So providing technology like inkjet printing to make it scalable and then other researchers also from the same subject try to make It more stable.

00:08:14: nobody would build up a solar cell On top of their roof which will need To be mounted back two or three years later.

00:08:21: since The efficiency is so good.

00:08:23: industry Is now catching up but there's no supplier yet where you can really buy?

00:08:28: With a guarantee above twenty five thirty Years um But yeah i hope This will happen in the next five, ten years.

00:08:36: I'm very curious to hear more about that and a future.

00:08:39: if you think of your eighteen year old self what advice would you give?

00:08:44: The eighteen-year itself is just standing in front of there at five years or studying And i remember when it started.

00:08:51: It was really overwhelming.

00:08:52: There were lots of subjects A lot new stuff New city Just learning Learning Learning Some all feel like probably also missed some time and the good moments that could have had back then.

00:09:05: So taking a break, taking vacation even though you're studying it's hard I think is quite important to mention.

00:09:20: Do you still do this?

00:09:22: Yes, when we studied electrical engineering I started studying it with my best friend and we both came up just before the exams that we figured out.

00:09:32: Whoa!

00:09:32: It was a lot of stuff that we had to learn... ...and lessons are months ago and the exam will be next week.

00:09:38: so it would be good to have a course that kind-of sums everything up and explains what is necessary for their exams.

00:09:45: So we basically just after every exam, even before we got the grades of that exam if you failed or didn't fail.

00:09:52: We made a video about everything that we knew and try to put it into small videos Just like Every Small Subject There is.

00:09:59: Break It Down To A Really Really Small And Short Video.

00:10:04: Now Its Close To Twenty Thousand Subscribers.

00:10:06: Where Can People Learn More About Your Field?

00:10:09: Is there Something You Would Recommend To Look At?

00:10:13: Yes, I mean in Germany we have this talk the open door and it exists basically every institute company.

00:10:23: so when someone is interested you can just go there.

00:10:27: There are all experts working at Fiat for years to explain what they're doing.

00:10:33: show samples.

00:10:35: some experiments showed a lab showing building everyday life.

00:10:40: Thank you very much.

00:10:42: Raffael, it was lovely talking to you!

00:10:44: Thanks a lot for having me and all the great questions.

00:10:46: Are YOU new to lighting or ready for more?

00:10:50: Follow your curiosity Start small And keep growing.

00:10:54: There are degrees Part-time courses and events To dive deeper into Lighting.

00:10:59: Find further information in the show notes at lichtpodcast.org.

00:11:04: You have been listening to Lichtwürgen a joint project of the lighting societies Germany, Austria and Switzerland.

00:11:11: Thank you for listening!

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