The next generation of solar cells, featuring Dr Elizabeth Tennyson

MONDAY, 19 OCTOBER 2020

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The next generation of solar cells, featuring Dr Elizabeth Tennyson
Released 19^th October, 2020

BlueSci 0:05

Welcome to the BlueSci podcast, brought to you by Cambridge University Science Magazine. I'm Ruby, and I'm Simone. Every two weeks we speak to local researchers, university staff and students and anyone who works in science to learn about their research and activities, hear about the work that they do, and uncover what goes on behind the scenes. If you want to get in touch with a question, suggestion or just want to be featured on the podcast, just drop us a tweet. Our handle is @bluescipod and you can also email us at bluescipodcast@gmail.com

Simone 0:39

This week, our guest is Dr. Elizabeth Tennyson, a postdoctoral researcher and Marie Sklodowska Curie fellow in the Department of Physics at the University of Cambridge. She works on a new class of materials called perovskites, which in the last decade or so have become incredibly exciting for applications in the solar cells. She tells us about her research using optical microscopy techniques to understand these materials, how she ended up working in renewable energy, what it's like working in such a fast paced and hyped up field and her experience is translating research from the lab to real world applications.

Ruby Coates 1:29

Well, thank you so much for coming and speaking with us today. Could you tell us a little bit more about your postdoctoral research and what what exactly it's focused on?

Beth 1:37

Yeah, um, thanks for having me, also. So there are lots of different types of solar energy, it's a pretty broad statement. So there are many different types of solar energy resources out there and materials out there. And so I'm looking at particular what's called the multi junction solar cell structure. And so most solar panels that you'll see out on the field are out outside are silicon base. And I'm looking at putting material on top of silicon and that material is a perovskite light absorber. And I'm looking at the interaction between that top layer solar cell and the silicon underneath. And I'm doing that from a very fundamental point of view. So there's people that work on the fabrication side, which is not me, I do characterization. So once the device is made, I do microscopy in order to understand. Okay, how can we make and design this better? As a broad or overview?

Ruby Coates 2:46

As a biologist, you know, I've heard a bit about solar energy, but you know, these solar cells, I look at them, and I just think, how does that turn sunlight into electricity? I it's just always blown my mind. So would you be able to give me a really simple explanation as to how that works, sort of in context of, you know, the solar energy field?

Beth 3:08

Yes. So how solar cells work. So they're, they're not, you need a specific class of materials. So they're semiconductors. And so there are three main material classes, there's the metals, the semiconductors, and the insulators. Metals won't absorb, they're just conducting electricity all the time, so that you can't really, really harness it, or control it. And insulators, if you shine light on it, it's not enough energy, they're not getting enough energy, to be able to start producing electrons and electricity, just you won't excite them with the sun. And so semiconductors is middle ground material, where when you just give it enough excitement, they can start conducting electricity. And that excitement comes from the sun or, or light in general, and specific wavelengths of light and the sun and there. So solar cells are optimized to be able to absorb sunlight well, and that's where that's where I was calling that bandgap. That's what defines the difference between the different materials anyway, so really big bandgap is an insulator, like, it's I'm using my hands, but

Simone 4:24

Your hands are far apart!

Beth 4:29

So any sort of radiation, you're not going to be able to excite electrons into it to start conducting electricity, but that you need that sweet spot. And so the photons that come in from the sun, are just just the right amount of energy to excite electrons, and then they start conducting electricity. And so that so that's how they work. You need that excitement and then you start you they almost act like a metal and that's how that works.

Simone 5:00

So for our listeners that haven't heard the word perovskite before, could you tell them what is it?

Beth 5:06

I didn't know how far we should dive in. But perovskites, it's another semiconductor material like silicon. And it's different, very different from silicon in that silicon is quite brittle and breaks easily. And you need to make a very thick layer of silicon in order to absorb light well. And so when you place perovskite on top, perovskite's another semiconductor material, and but it's solution based, and so it's really easy to, to make just from chemical based on chemical solutions. And so you can make a very thin film of the layer, and it can be placed on different types of substrates. So it can be flexible, for example. And that's one of the big applications, I think, for different solar cell materials and solar energy in the future, as well. Because silicon can, cannot be flexible. So So perovskites are exciting, because they they can be and they're solution based and they also are very tunable whereas like, so their structure is this inorganic, organic mixture of atoms. So silicon is just silicon atoms. Perovskites, and I should, I should say, kind of caveat this with halide perovskites, because there are, there might be listeners that have, they think perovskite and they think of superconductors, because that's also another class. So I'm thinking, specifically halide perovskites, which are semiconductors, they're made of organic inorganic materials. So often they have this inorganic component, or organic component, sorry. And, and then you can place a lot of different types of halides in different kinds of metals, for example, lead and tin can be found in these so there's, they're very tuneable material, which is why I think they're interesting, and you can change which lights they absorb. I mean, they're very versatile. So that and they're new. So they're, they're kind of exciting, as well. So I'm looking at those materials on top of silicon.

Ruby Coates 7:22

And, and because these, this, this new method, the perovskite, it seems a little bit more adaptable and a little bit, slightly more complicated. So with that, does it does it bring any issues in terms of sort of optimizing it for what you want to use it for?

Beth 7:41

Oh, yeah. So there's, there's- and that's kind of what makes it fun in a way, but it also yeah, it there's a lot we don't know about this material. So perovskite, because they have this organic component as well have, and they have a lot of different atoms inside their crystal structure, they're known and prone to degradation. Like that's a pretty common issue. And the stability is is a problem with these materials, because they are, they can change with different amounts of oxygen exposure, different amount of water exposure. And also, there's the thing that we call halide segregations. So oftentimes, the halides, which is a type of atom that we we, that's within the structure, and it's either often iodide most often, and bromide, and when you have a specific concentration, so like, say 30%, is bromide and like 70% is an iodide within the crystal structure, you can get what's called segregation, halide segregation. And so you can get just clumps of just bromine in some regions, and clumps of iodine, which is something we try to avoid. And actually, we're trying to understand how that happens. And, and design materials, because you could, you might actually want that in certain applications as well. It could be advantageous, even perhaps, but for most applications that advantageous and you'd want to avoid segregation wherever possible.

Simone 9:19

So it sounds like there's a lot of different ways that you could manipulate perovskites for different applications, because they're so versatile. So I guess in terms of the work that you do, specifically, how do you how are you able to probe those properties and understand maybe how changes in structure correlate to changes in the interaction with light and things like that? What kind of techniques do you have to use for that kind of investigation?

Beth 9:42

Yeah, so yeah, because - You're right, I don't- I don't do the fabrication, I do primarily the characterization. So I am studying what happens when we expose perovskites, specifically the types of materials to light or different things. So I use many different types of microscopy to do that. The number one way that I, at least during my postdoc that I've been using is optical microscopy so that you uses localized sources of light. So most of the materials will function, if you give them light, you start producing electricity, I'm focusing that light down to the micro scale, and shining just single wavelength of light and looking at a mission that we get out of the solar cell. So it's a common rule that you know, to whatever you absorb, you also must emit. And so it's emitting, and that emission that we collect from the solar cell, that tells us how, what the local performance is like there. So I use the emission from our solar cell, from the solar cells that we have, and sort of any low areas where there's not much emission, that means there's likely not very much electricity or happening in that region. And so by analyzing with microscopy can say, Okay, this is, this is an area where we're, we're losing electrons and holes. on the same side, we can also look, the emission is happens at a specific wavelength, and we can detect those wavelengths. And when you have a more bromide rich region, like I'm sort of saying with this highlight segregation, when you have more bromide rich region, that emission is a different wavelength than if you have an iodide rich region, for example. So how is segregation with techniques that I use is actually pretty easy to detect, if you know the emission wavelength, and, and so that helps us to identify segregation. There's also other techniques that I've used, called scanning probe microscopy. So that's using a very small nanoscale tip, and it's dragging along the surface of your material of interest. And that gives you height information, but as well as electrical information like current and voltage, so I can actually get with a local current or voltages of a solar cell and figure out, okay, we're having voltage and current losses in this location, and then maybe use another microscopy technique to decide to figure out why are we having that. So not only is it about identifying, but it's also diagnosing, in a way, but using microscopy and looking at the fundamentals there.

Ruby Coates 12:32

Wow, it seems like there's an awful lot to characterize in this sort of really intense, real deep understanding of how these new materials or you know, use in a different way, and how they sort of interact with light, and things like that. And it's far more complicated than anyone would think, you know, even to just design something like this, or even characterize how exactly how it works. And, and so, although this is a fairly new technology, and if you're using this sort of optical microscopy to look at all of these characteristics, and did in terms of your career, did you start off doing this in your PhD? Or is this a relatively new thing in your postdoc? Have you always been interested in solar energy? Or is this a fairly new thing?

Beth 13:22

Yes. So I love this question. So yeah, it was a journey to get here. Actually, it was, um, so I was not originally doing solar energy research. So once I got out of high school, I think I knew that I wanted to do something more in the physical sciences, but I wasn't sure quite what. I went to the University and went to their orientation. And I was like, you know, maybe I like space. And so I just went over to the astronomy area. And, and I asked, and they're like, yeah, take a course with us, you know, super friendly. So I took a course I'm like, Yeah, okay, I'm really enjoying this. So I decided to major in physics with an astronomy emphasis. And technically, I have a degree and my bachelor's is in that but I did decide to forego the astronomy emphasis and just do the physics part because I thought that would make me more marketable to graduate schools. So because I knew I was changing fields. So I still have this affinity, strong affinity to astronomy. And but I did change around my third year of undergraduate because, um, you know, originally I went in, I'm like, I'm gonna find life on another planet. Like, this is what I had decided what I really wanted to do. But I just like, okay, I kept realizing that I might, I maybe wanted to focus more real time and have a bit more impact in this century. And I think climate change at that point, so this was was really starting to come to the forefront of communication, I kept hearing about it and felt pretty passionate about what was going on and concerned as well. So it's like, maybe I'll maybe I'll work on this part first. And then you know, I still think about how I can get back. I still love I still love astronomy and things. But yeah, so so. So then I was asking around professors, I was like, What should I do if I want to switch? And I still say with astronomy, right, because I use sun. But no, I thought I thought renewables and I think I was I was most excited by solar. And maybe it's because I like astronomy, but I thought solar is also seems to be the best more of most abundant renewable out there to help combat climate change. So I want to do solar energy, my PhD. And then once I made that decision, and then I was only looking at programs for PhD that that did solar. And then the the Professor I ended up working with she, she was an expert in characterization techniques. And so I started doing analysis and characterization of solar energy materials in general. And actually perovskite, the material that I was mentioning before, it actually, it sort of became and got got its ground during my PhD. So originally, I was not even, it was not even in my field of view. I started my PhD in 2013 and perovskite was like, a whisper, you know, I think it had been discovered as a solar energy material back in 2011. So it was very, you know, I think I studied my first perovskite, back in 2015. And so that was like, two years in my PhD. So it was I the beauty of doing characterization, though, is that you can look at any material, especially if it's all kind of in the similar realm. And yeah, it's material independent, if you're looking at semiconductors, particularly. So that was kind of nice. I was I was developing characterization techniques, mostly in my PhD, but I wanted it to be in the realm of solar energy and stay with that. And then prospect got on the field. And it was it got wild, you know, they, they say it was sort of like similar it and I don't know if your listeners know, but like about the like, similar to the graphene revolution, right? It's just became so wildly popular and exciting. And, yes, so that, I mean, it's continued. I think it's still a very exciting material, but we're learning more about it. And we know what works and doesn't work a bit more. And then yes, so I did more characterization. And then I want to focus and I think, move to a different system where I think the field is going. And multijunction with perovskite on top of silicon, I think is kind of exciting, and how we can boost efficiencies forward. So I'm still doing something similar to my PhD. But yeah, that was not I was never always a solar. So energy person, but I love it. So it's good.

Simone 18:05

And it sounds like over what you're saying the fact that the perovskite boom, let's say it was similar to what we've seen with 2d materials and the graphene boom, what would you say? That you notice the way in which research was being carried out ? Did you notice like a difference in like, I don't know how the literature or how fast it was being published or kind of how does that hype affect research? And were you able to see that change from the inside? I think that's really interesting to hear about.

Beth 18:30

Yeah, yeah, no, it's it was just like a wrecking ball coming in, it really was because I was looking at I was looking at poly crystal in semiconductors. So that's what a perovskite is. Silicon is mostly single crystal often so I was looking at I was looking for some materials that were made up of these grains and and trying to understand them and perovskite is one of those. And the material I was looking at is called cadmium telluride. That's one of them. And I don't know if you've heard of that, but like, yeah, it's not nearly as as hot of a material, or cigs, which is copper indium gallium selenium. So these were the two materials I was focused on trying to understand a bit more because they they were thought of as sort of the next thin film like they could be flexible. Those were at what I was looking at and then perovskite came in. And I would say the field just evolved so quickly, everybody, like it was almost as if cadmium telluride and CIGS now there weren't that many papers on them, but it's like, everybody forgot that they even like, except for the people that had companies and things like this. It seemed like it was if you didn't jump on that perovskite train, like you were gonna miss it. I it was, it was amazing. And, um, yeah, so I think being seeing that and I think that helps build huge networks of people that you could talk to, because when everybody's working on a similar problem, you just, you just the amount of people that you end up working with ends up being huge. And whereas when I was doing starting with cadmium telluride, there was like a few groups that I knew was like, oh, yep, there, those are those groups. What's more nice. When you get to perovskite, it just got to be everybody. And it was, it was really an interesting thing to see. And then you have to sift through that literature. You can't You can't keep up. I mean, that was, it was just wild, you were trying your best to keep up with what was going on. There was constantly a new efficiency announcement. A new it was it was wild. Now it's timed out, I think. But we were, itwas going crazy for a while.

Ruby Coates 20:49

Wow. And obviously, the benefit of that is that it's exciting and lots of people in the field to network with and collaborate with. But I guess the sort of flipside, is that of that is that there must have been an increased amount of competition in that area. And is there? Is there still a high amount of competition in this field research? And if so, how do people do their best to sort of carve out their tiny little niche within this sort of revolution?

Beth 21:18

Yeah, within the perovskite, particularly there, there was a crazy amount of competition, I think we were at an advantage as we were looking at characterization techniques, I think the competition was mostly within fabrication. Everybody was trying to fabricate the best device. So if you could gain a 0.1% efficiency and get that next record on the famous solar cell efficiency chart, like that was that was that was the game. But for from my point of view, I was just trying to study them. And so the pace didn't necessarily need to be as as fast as the efficiency pace. And now the thing is, I do, I did want to make sure I was imaging relevant materials, because like I said, you can add different types of atoms. So people were playing with the structure, the elemental structure and composition of these materials all the time. So I wanted to make sure I was still imaging relevant materials, because there's some that were like, Okay, at this is always never going to work, we're going to sort of ditch it. But I think, as a characterization and developing those types of techniques that not anyone else can use, or are novel enough that you know how to do them, well, then people will send you their material to look at and investigate. And I think that that's one way that characterization can be really handy. If that's what your niche is, and then there's, there's also I mean, I've been amazed that machine learning techniques that have come out because of perovskites trying to figure out what elements you want to use, or when degradation might happen. And that's, that's become sort of a part of the perovskite community. There's a perovskite, LEDs, different applications, so not just using for solar. So I think that helped. I think people use what they already knew, since profits were new, they use what they already had, and made it just about perovskite instead. So I think that, I think in the end, it didn't end up. They were still just using their original stuff, but just applying it to profit at that point.

Simone 23:28

Yeah, and I guess in some way must have been nice to have such an abundance of data from a kind of understanding perspective, to be able to, to have all these things to choose from and be able to see all these different parameters actually, like carried out and then be able to compare that to like, Okay, well, then why is this happening? Because I feel like that that's one of the problems when you're trying to understand something is that if you don't have enough things to look at, then you kind of are stuck with, well, you know, this is how this works. But is this really generalizable to like the whole system? So I guess there's probably some positives as well.

Beth 23:58

Exactly. And well, one of the things that was interesting, too, because this type of material is solution processed, it was the first time that I had started working with chemists, because I was a material scientist doing my PhD there. And that was what a lot of the solar energy field was physicists, material scientists. Now there were people doing organics as well, that had more chemistry background, but this brought a lot more chemists into the solar energy field. And so that was, you know, bridging the knowledge there, you could see that you needed to communicate differently and make sure everyone was on the same page there too. And I think that helped you gain knowledge in that in that sense.

Ruby Coates 24:38

Yeah. And so yeah, it sounds like the the field itself is quite interdisciplinary. And how did you find that, you know, like you said, You it kind of put you into contact with chemists. And for the first time, how did you find that sort of how the conversations when the exchange of science was fairly easy or Was it a little bit difficult to try and translate what each side was trying to put across?

Beth 25:05

I think I think it just, it's overall, you just need to make sure you're very clear. It's and I think that's true in any discipline, even, even in different institutions, people have ways and certain technical words for things, that you're just like, Wait, what? Whoever, that and then so you just have to learn the lingo. Once you, once you clarify what the lingo is, then then we can move forward. And so I think from for me, it was just about clarifying and understanding what's important because when and what parameters matters. So as a someone who analyzes the solar cells at the micro scale, I care a lot about how was it made. And, you know, what are the what are the conditions that I should be imaging this under? Things like this that I didn't have to know before? Because it's, like I said, they are they have some degradation issues. So often, you want to low humidity environment, low oxygen. And so I needed to know those kinds of information. Whereas with growers, they care a lot more about Okay, this is, this is how much material I need. This is about this is the spin rate I need to be doing the processing and, and so it's just about what what parameters are the most important and understanding and making sure that you both know, which are the most important parameters for each other. And, and I think that that was the learning process, like, okay, it's important for you to know that I'm good, good. And now I need to know this and make sure you keep that in mind when I'm yeah. So but overall, it's just getting that initial and then and then it's fine.

Simone 26:43

And in terms of looking towards the future of perovskite , that solar cells are going, do you think the main, obviously, there's all these new applications in in flexible devices, and so on, where we know for sure that, you know, it doesn't matter how amazing you can make a silicon solar cell, you cannot make it, do these, you know, fancy things? Do you think that's the main advantage that perovskites offer? Or how do you see the kind of future in the field?

Beth 27:08

I think so there's two full to two ways, I think. And why the why I'm studyinh the materials that I'm studying. I'm studying perovskite on silicon, because I think the most relevant application of perovskite is when it's put into a multijunction and not on its own. And because when you look, what do you think about solar cells and, and being looking around, it's mostly on the field in the fields. And that's where a lot of the large scale energy generation is coming from. And so I think adoption is going to be easier if you're using a base, silicon material that's already existing and part of the economics of scale, it's already in, it's already commercialized. So if you just add a material on top, it should be in principle much easier. And that, that seems that seems a lot more easy to introduce into the into the industry. And now it's all about stabilization, and making sure that it is efficient. But I think there's a company that's working on that right now, on solar PV, they have they've had this, they're making large scale, and it looks like they want to deploy profit on silicon solar cells. And I think that's where they're going to be the most powerful or most impactful. That said, I think that there is a place for perovskite in and more niche markets for perovskite on different different types of substrates flexible, I would like to see them as building integrated, that's one of the things I think is super cool is because they can be semi transparent. So you could coat a window with perovskites, and they can be colorful, and so you can make these kind of really pretty facades that are actually producing solar cells Now, again, that are producing electricity, but that's pretty niche. And it's hard to see how that since there's not already a market for that or not a big one, it's hard to see that really being impactful, but I think it could be and and i think there there is a place for it. So it's kind of exciting too.

Simone 29:20

And in terms of these these new these hybrid solar cells, so to speak. Um, what is the advantage of adding a perovskite on top of silicon? Like, how does that affect how the solar cell works, I guess, how does that change?

Beth 29:32

Yes. And that's that's exactly what I'm trying to study. So the, but the reason why you want to do that. So if you have just silicon on its own, there's a theoretical fundamental limit of efficiency that it can achieve, which is about 30%. And when you place the perovskite or another solar cell material on top, you automatically get a fundamental limit jump increase, almost 10%. So we can get a maximum efficiency of nearly 40%, which is huge. And I know it sounds small, but in the field, it's huge. And it would be a major cost reduction, think about a same panel the same exact size, but it's producing more electricity, that's going to be way more valuable. So you can produce more electricity. Out of out of that, when you have multiple solar panels on top of each other, just fundamentally, now, how it works is, silicon is a perfect material for a base, because it absorbs it has a very what we call a very low bandgap, which means that it does not take much energy to start producing electricity. So you can have pretty long wavelength, low energy, hitting the silicon and it will start producing electricity. And it's good, that's a good base. So you put a material that has a slightly larger bandgap that can't absorb those lower energy, but silicon can, so it'll make up for it. But it's really good at absorbing high energy. So for example, if you have a very high energy photon coming in and hitting, right, now it might produce a lot of heat in silicon. And that's caused loss, and you don't want that, but the profit on top would reduce that amount of heat. And so you get less heat loss. So you have your your more effectively getting and losing less to heat. And that's why the fundamental limit goes up, because you're just more efficiently collecting both high energy and low energy light.

Ruby Coates 31:33

And so what's kind of struck me about just this whole discussion around solar energy it seems to be would it be fair to say that it's fairly commercially driven in terms of what what you want to produce, or, you know, you want the highest efficiency materials in order for them to go out to market and be used worldwide. And, and so in light of this, you're actually involved in the affordable perovskite solar irrigation system project for smallholder farmers in Ethiopia. So I guess this is a slightly more sort of. And so adding towards sort of international development, and those types of initiatives. And so would you be able to tell us a little bit more about this, and what the overall aims are?

Beth 32:22

Yeah, it's a, it's such a great project. And I will admit, I mean, it's, it was born in April of 2020. So it's very recent, but it's, it's a great project. And I'm happy to discuss so what what it's a great collaboration between the PI that I'm under and then there's Laura Allen from the center from global equality in Cambridge. And then there's also Tim Long in his group from the Institute of manufacturing. So those are the three PIs in Cambridge, that are leading it and and Laura, in the Center for Global quality is the bridge between Cambridge and Ethiopia. So she knows the collaborators and the PI that are working in Bahir Dar Institute of Technology. So we're and and there's a few PI's in, in BIT, or that that university that that she knows that we started collaborating with, and they wrote this project together. And so the aim and what the problem is that they've identified in their area in Bahir Dar is that farmers, and oftentimes, the farmers are female in that region, have to get water from a local source, and then bring that water over to the to their farmlands. And then they constantly do that, in order to water their plants. And they're looking to make that system more efficient. And they've done some trials already on water pumps. So if you have a water pump there, where you get, you have a local source nearby, you take a pump, and then you're able to sort of use it as a hose over your farmland to help water your crops. What that does is it reduces the amount of labor is because otherwise, it's a very labor intensive, it reduces time and it increases your copy of which is going to make more money. And in the long run. And so there's like a lot of wins for that. And that so that's the problem they identified and they also realize that it's a it's a gender equality issue as well, because it does seem to be women that are doing these roles, a lot more than the males. And so what this is the sense they've identified that they wanted to we were looking at trying to use solar powered water pumps in that region, and that's where Sam, my PI and I come in as the and then there's also another postdoc, Bart Bruce on on this as well and that's where we we come in with the solar part Tim Long and his team are doing the power electronics part. And then we're also working with the actual academics and in Bahir Dar to work on like the where do we locate it? We were supposed to be going there and doing field surveys to see where it where we need to place them. But unfortunately, that didn't work out. But yeah, so so we've been online and having some communication figuring out. So they've been the folks in Bahir Dar there have been doing surveys of farmers and asking them, what do they need, how much land so we're trying to get the data, so that we know how large a solar panel needs needs to be. And then the idea is also that they have some PhDs that would come here and learn about prospects actually, because in in Bahir Dar that's not, they don't know anything about anything with the solution, processed solar cells, they only know, mostly silicon. And so if one one application, for example of perovskite could be to make a flexible panel that could be a water pump, and, and then you could be portable. And that's something to farmers would would love is a portable, lightweight water pump, solar powered planet water pump, because what they would do is they use that solar panel in the day to water their crops, and then they would go home. And once they're done watering, they would go home and use that solar panel for whatever else they wanted. So it would be a multi system, and that would be something that they really wanted. So but the overall aim is that they would learn how to make the pumps overall. And then Long, long term goal is that they start manufacturing them in, in Ethiopia themselves. And so that, yeah, they can grow the economy. But that's, that's that's the, that's the long term goal. But right now we're just talking about, okay, how do we implement making sure that we have the right products, and we know what they need before going ahead and making something? And so is the main advantage with the prospects and the like, they're more lightweight and portable, whereas silicon will be a bit more like, difficult to move around? Or is there some other advantage? Yeah. And we would, we would, yeah, so mostly, it's about the portability, the thing, we, the thing is, we would start with silicon, just because we want to make sure if it works, and that would be a first starting point anyway. And then there's all these different shoot offs from the project. So then it's about making tandems. So that's what the multijunction perovskite on silicon, because then you get more energy, but you might not actually need that much energy for just to water these just to use to power a water pump, it might be a bit redundant. So then it's all about, okay, well, if you're going to be portable, how far you walking, and, and so is that important for the light is lightweight, going to be very useful for you or not, and then making sure you get enough electricity, and then it's designed as well, so that it gets what they need, and then a little bit extra, so. But yeah, that's why that's why it could be adaptable. And then they would change it to whatever they wanted. Once they know how to manufacture it. They could they could tune it. But yeah, it's all about, it's really about the knowledge sharing, sharing. So for me, I think it's really interesting to learn about international development, I'm really passionate about that I think all of the changes that are going to come up are our local problems and need local solutions. So I think I'm finding that and realizing that is is kind of the next step forward is like how do we how do we solve certain issues? It's always been local, local solutions are necessary.

Ruby Coates 39:02

Yeah. And that, that, I think that's really important as well to sort of engage with basically the users of the technology as much as possible. And that, in itself, requires a degree of sort of excellent scientific communication skills and being able to, to sort of take in what people need and, you know, coordinate that. And outside of your research, you're actually engaged in a lot of scientific communication yourself, and some other podcasts, some other podcasts and you do a lot of outreach. So, yeah, how did the public respond to sort of learning about renewable energy and people engaged in a fun exciting or, or do you find that it's, you sort of have to whip up the excitement?

Beth 39:51

Yeah. So I would say I'm of all so I do do a lot of outreach and I enjoy it and depends a lot on your audience. So one of the program programs that I am co organizing with, that's that's targeted at 10 year olds in primary school. And they are, they're just learning about it. So they're very susceptible and open but don't necessarily understand fully about the climate change crisis, but they do. You know, they see wind turbines and solar panels, so they sort of get it. And I think it's all about trying to get it. And I think that's really what we care about. But then when I'm, when I'm working with older, older students, or even adults, and then I've been discussing with I think, most people, it's always a natural link, they start talking about their, their, they know have a neighbor that has solar panels, or like they have an electric car that always that always seems to be linked up. And I get why hadn't made that connection. But I think it's really, it's really interesting, and most people are really excited. There's only been a few times where I think there was some like, Well, what about the government's and regulations and having issues with how how government's regulating renewables. But actually, to be honest, one of the reasons that I got into renewables, and specifically solar, besides loving astronomy was was because I thought, How can it be controversial? You know, the sun is there. And even if there wasn't climate change, like even if that wasn't a thing, I think people would still be like, Yeah, that makes sense. Let's get energy from the sun. That makes sense. So I think that was one of the reasons I was like, yeah, you wanted, I thought that that would be something that everybody could just agree on. And so there hasn't been much pushback. I think people are really excited and want to see more. That's always what I get. And maybe it's just because I'm preaching to the choir. Most people who come to renewable energy. No, I think I think people realize that there's a transition happening and are on board.

Simone

I think that's a great place to wrap up. Thanks so much for talking to us today!

BlueSci

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