Kristen Tagaytayan carefully unearthed her research sample from a nitrogen glovebox. She gingerly placed the sample onto her workspace and added a nickel chemical solution to it. Using a razor blade, she evened out the mixture across a glass slide and placed it in the lab’s oven, where she watched it cook from behind the glass window.
If you asked the first-year mechanical engineering graduate student a couple of years ago where she’d be today, she never would have guessed it would be conducting research as part of a NASA fellowship that could change the future of space travel, energy, and maybe even the world as we know it.
Flashback to her sophomore year as an undergrad at UNLV: Tagaytayan had been feeling dejected when she realized physics wasn’t her calling. She thought this meant her childhood dream of working with NASA wouldn’t pan out. But as she passed row after row of wind farm turbines gleaming in the sunlight during a drive back home to California later that semester, she found the spark she needed.
“Once I got back to Vegas, I felt inspired, and I wanted to do something related to renewable energy,” said Tagaytayan, who’d also recently begun worrying about energy alternatives to combat climate change.
That passion for solar energy research led Tagaytayan to focus her graduate school career on joining UNLV’s Bansal Research Group. It's thanks to the lab and her mentor, engineering professor Shubhra Bansal, that Tagaytayan found the heart of her research in a material known as “perovskites.”
The term perovskite might look intimidating at first, but it simply refers to the mineral’s crystal-like structure. While perovskites look like a black piece of glass to the naked eye, it’s that crystal-like structure — which provides the perfect slate to absorb a considerable amount of energy at a low cost — that makes it a big deal for mechanical engineers like Tagaytayan.
Her research falls into the niche of solar cell technology in a topic known as bandgap engineering. The bandgap is the minimum amount of energy needed for a solar cell to start producing electricity. When scientists convert sunlight to energy, sometimes some of that energy isn’t transferred efficiently and burns off in the form of heat. Tagaytayan’s job is to mix chemical additives atop the perovskites’ surface and create perovskites of varying bandgaps aimed at figuring out how to more precisely convert those sun rays into electricity.
The implications are boundless, potentially resulting in financial and time savings for everyday Joes by lowering the cost of mass-producing everything from rooftop solar panels to air conditioning units to cell phones or even — to NASA’s point — literal out-of-this-world technology like galactic aircraft.
Earth’s Mysterious Neighbor
Though perovskites are small, Tagaytayan’s research is taking them out of this world with the help of NASA. Her research proposal, which earned her the fellowship, focuses on using perovskites in space probes — specifically, for expeditions to Venus.
Despite Venus being Earth’s closest planetary neighbor, we know little about it largely due to its hostile environment. Venus has a surface temperature of roughly 900 degrees Fahrenheit. Tagaytayan explained that Venus’s extreme temperatures make it nearly impossible for NASA probes to withstand its surface — nearly.
That’s exactly why Tagaytayan’s perovskite research caught NASA’s eye. “We’re developing materials that can withstand those high temperatures but still be efficient at making electricity or energy,” she explained.
Perovskites are particularly of interest for a Venus expedition because of their highly effective energy absorption capabilities. At full capacity, perovskites rival gallium arsenide, the material that does the heavy lifting in most solar cells and is used by most NASA crafts.
In addition to working on the project in the lab with Bansal, Tagaytayan will personally visit one of NASA’s centers every summer for 10 weeks as part of the three-year fellowship.
“I think it's really cool how, despite some early bumps in the road as an undergrad, I still find myself beginning a relationship with NASA, and it's based around research that I’m passionate about,” she said. “It's great being supported by an organization that is helping us better understand not only our planet but those around us.”
The Woman Behind the Lab Coat
Tagaytayan has high hopes for the future of her research. In addition to space technology, perovskites — which have low carbon emissions — could prove to be an inexpensive alternative to fossil fuels.
The possibilities excite her not only for the world of STEM in general, but for those of other women looking to enter the male-dominated field.
Tagaytayan’s love for the craft is one of the many things that gives her the power to overcome the hurdles in her research, and the ones she faces being a woman in STEM. She described how a friend in another STEM-related field once found herself in a class where she was the only woman in a class of 20 students. The male-to-female ratio is only more disproportionate in Tagaytayan’s field. Statistics indicate that women only made up around 27% of the STEM workforce nationwide as of 2019.
“That's why I’m doing all this work. Even though it's still a learning process for me, I enjoy it because I know it’s one step towards carving a path for future generations.”
As a woman who’s inspired by guidance from Bansal, another woman in STEM, Tagaytayan knows all about the difference it makes having a female role model in the world of STEM. That’s why she leads the local engineering honor society, Tau Beta Pi, as president. It’s here where she not only tries to set an example for fellow aspiring women engineers, but also engineers as a whole. “In engineering, there's a lot of focus on technical skills and just knowing how to make things. But we’re all people, and we need to sharpen those verbal skills and focus on connecting with colleagues too,” she said.
Tagaytayan has some time to go before graduating with her Ph.D., but she plans to continue her research in renewable energy in the future. Some advice she has for fellow students looking to pursue a similar route? Find your passion.