In her research work, Jokotadeola Odutola provides new information about the solar-to-chemical conversion routes in graphenes and graphitic carbon nitrides, both of which are two-dimensional carbon-based materials. Solar-to-chemical conversion happens when a photocatalyst, a material that absorbs sunlight, captures and stores solar energy. It does this by reorganizing the structure of a common chemical to produce a useful solar chemical which can be used directly as a fuel or indirectly as a raw material for other chemicals to meet our rising global energy demands. This way, solar chemicals can solve the issue of sunlight being inconsistent in times of cloudy weather or shorter daylight hours. In addition, they present a cheaper, more climate-friendly and versatile solution to the problem of solar energy storage, compared to popularly used batteries.
The pace of technological developments in the field of solar-to-chemical conversion has been slowed down by their low conversion efficiencies. Earlier studies have shown that the performance of photocatalysts depends on what happens to their electrons and holes after absorbing sunlight.
“This is where ultrafast laser spectroscopy acts a powerful tool, it works like a superfast camera at less than a trillionth of a second, to collect information on how long electrons and holes stay available to react with chemicals at the surface of the photocatalyst after absorbing light,” says Jokotadeola Odutola.
In her research work, Odutola used ultrafast laser spectroscopy to closely study how changes to the structure of graphene and graphitic carbon nitride photocatalysts affect the behavior of their photoexcited electrons and holes with regards to solar chemical production. As a result, she was able to show for the first time how nitrogen defects in graphene can trap plasmons (collectively photoexcited electrons) so that they are still available to produce solar chemicals for a longer time.
“I also demonstrated how photoexcited electrons in carbon nitrides can remain active for a longer time by quickly moving them to a nearby photocatalyst. The separation of photoexcited electrons was also achieved by altering the structure of the carbon nitride itself. This was achieved either by using templates to shape their structure or by adding chemicals to increase the amount of nitrogen defects”, she explains.
Odutola's research will improve our understanding of photocatalytic processes in carbon-based materials. This knowledge could be used to develop better energy solutions for solar chemical production and solar energy storage.
Jokotadeola Odutola is originally from Nigeria. She currently works as a doctoral researcher in the Smart Photonic Materials and Spectroscopy and Light-Active Materials Groups at Tampere University.
Public defence on Tuesday 3 June
The doctoral dissertation of MSc (Tech) Jokotadeola Odutola in the field of Chemistry titled Charge Carrier Dynamics of Graphitic Carbon-based Photocatalysts for Solar Chemical Production will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 12:00 on Tuesday 3 June 2025 at the Hervanta campus in the Tietotalo building, TB109 Auditorium (Korkeakoulunkatu 1, Tampere).
The Opponent will be Professor Mika Pettersson from University of Jyväskylä, Finland. The Custos will be Professor Arri Priimägi from the Faculty of Engineering and Natural Sciences.