"My research aims to develop and evaluate the performances of micro gas sensor devices with gas sensitive material"

Milena Tomić is defending her thesis today and we decided to ask her some questions about her time at IMB-CNM and the research she carried out. She talks about her thesis, Semiconducting metal oxide structures with surface nanoscale interfaces for gas sensing directed by Stella Vallejos, her time at IMB-CNM and her interests outside science.

Trajectory and research

Describe us your thesis.

The main objective of my research was to develop and evaluate the performances of micro gas sensor devices with gas sensitive material based on structured metal oxides (MOXs) that incorporate surface modification in the form of nanoscale interfaces between a ‘host’ MOX and a ‘guest’ material (i.e., another MOX, metal nanoparticles (NPs), or organo-functional molecules). In the first part, the thesis deals with the synthesis and surface modification of structured MOXs and analysis of their physical and chemical properties. Thus MOXs synthesized during this thesis were WO3, ZnO, and Fe2O3 tuned morphologically to obtain high surface-to-volume-ratio films and subsequently decorated with nanoparticles of noble metals (Au), other metal oxides (CeO2, Fe2O3, and CuO), or organic molecules ((3-aminopropyl)triethoxysilane - APTES). Moreover, the synthesized structures were characterized using different microscopy and spectroscopy techniques. In the second stage, the studies are directed to explore the sensing properties of the microsensors containing the synthesized materials and the influence of formed nanoscale junctions between ‘host’ MOX and a ‘guest’ material’ on gas sensing properties. The performances of the assembled sensors were verified by monitoring the oxidizing and reducing gases recognized as the most relevant for further application in environmental monitoring and/or medical applications, amongst which are ethanol, acetone, toluene, hydrogen, ammonia, carbon monoxide, and/or nitrogen dioxide. Results validate the materials and methods to fabricate miniaturized gas sensors and the paths to tune the sensor performance and operating temperature by incorporating controlled interfaces at the MOXs' surface.

How would you explain your research in plain language?

Developing new materials and their implementation into sensors, which can be used for different purposes - as air quality sensors, food quality sensors, sensors for disease diagnosis, etc.

What are the main applications of your research?

• Air quality monitoring.
• Health biomarkers (early detection of pulmonary diseases and diabetes).
• Food quality markers.
• Road traffic safety (in breathalysers - devices that estimate blood alcohol content).

Personal experience

Which are the scientists or role models you look up to (anybody is accepted)?

Nikola Tesla

What is the most valuable lesson you learnt at IMB-CNM?

Adaptability

What are your plans after you finish (it is okay not to have any plan)?

First to travel and sleep :), then I’ll continue my research at IMB-CNM during 2022.

About Milena

Interests and hobbies.

• Handmade natural cosmetics.
• Gym.

Choose one.

• Train or plane. Plane.
• Mountain or sea. Both.
• Pizza or burguer. Pizza.
• Netflix or HBO. Netflix.

Book recommendations.

• Jo Nesbø, The Bat.
• Ivo Andrić, The Bridge on the Drina.
• Walter Mischel, The Marshmallow Test.

Movie recommendations.

• We Are Not Angels (Part 1).
• Montevideo, God Bless You (Montevideo: Taste of a Dream).
• South Wind.

Music recommendations.

• Imany, Michael Kiwanuka, Sade, Amy Winehouse, Bisera Veletanlić, Ella Fitzgerald, Nina Simone, Anna Oxa, Neverne Bebe.