E.J. (Elleke) van Harten MSc
Research and Education Assistant
As a Research and education assistant in the Soft Condensed Matter & Biophysics group, I support and assist Post-docs, PhD students, visiting researchers, and (master) students with synthesis related problems and practical issues. Together with my colleagues Relinde van Dijk-Moes and Dave van den Heuvel, I manage the synthesis and biochemistry labs, we supervise (master) students, and we are responsible for ordering & registering chemicals, lab safety, and lab introductions.
Next to supporting and assisting others with their research, I develop new synthesis methods and improve existing procedures. My research focuses on the synthesis and characterization of colloidal nanoparticles. Below my main research topics are listed and discussed:
1. Colloidal luminescent semiconductor and perovskite nanocrystals
One of my expertises is the synthesis of colloidal semiconductor quantum dots with different compositions (i.e. CdS, CdSe, InP, InGaP, and CuInS2), sizes, and shapes (i.e. rods, dots, and platelets). In addition, I work a lot on the synthesis of colloidal heteronanocrystals (core/shell nanocrystals). Colloidal (semiconductor) nanocrystals are currently used in serveral projects within the Soft Condensed Matter group. More recently, I started working on the synthesis of inorganic perovskite nanocrystals (CsPbX3 with X= Cl, Br, or I) as well.
2. Colloidal (fluorescent) silica spheres
Colloidal (fluorescent) silica spheres form a very imporant class of model colloids. In our group, the silica spheres are often used as a model system in confocal microscopy and liquid cell transmission electron microscopy studies. Using the Stöber method in combination with seeded growth techniques, we can make silica spheres with a diameter in the range 100-1500 nm. These spheres can be made fluorescent by coupling of fluorescein (green) or rhodamine B (red) dyes to the silica. Using alternative techniques, like a reverse microemulsion method or an amino acid catalyzed silica synthesis, (fluorescently labelled) silica spheres with a diameter below 100 nm can be made as well.
3. Colloidal silica-coated nanoparticles
In addition to the synthesis of colloidal nanocrystals, I also have a lot of experience in silica coating of nanoparticles. Hydrophilic nanoparticles can be quite easily coated with silica by using these particles as seeds in a Stöber-like reaction. Alternatively, hydrophobic nanocrystals can be coated with a thin (2-20 nm thick) silica shell using a reverse microemulsion method. Thicker shells can be obtained by subsequent shell growth using seeded growth techniques. The coating of luminescent semiconductor quantum dots remains challenging, because the photoluminescent efficiency of these particles reduces significantly during silica coating. The coating of luminescent semiconductor quantum dots with silica, while retaining the optical properties of these nanocrystals is one of my main research topics.
The Soft Condensed Matter & Biophysics group (SCMB) has collaborations with other groups within the Debye Institute of Nanomaterials Science of Utrecht University as well as with other universities. If you are interested in collaborating with our group, you can contact Prof. dr. Alfons van Blaaderen (colloids), Prof. dr. Jan Lipfert (biophysics) or Prof. dr. Marjolein Dijkstra (computer simulations).
UU webpage Soft Condensed Matter & Biophysics (SCMB)
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Previous employment
In the 4 years before I started working as a research and education assistant in the Soft Condensed Matter group, I worked as a PhD candidate in the Condensed Matter and Interfaces group of Utrecht University under supervision of Prof. dr. Andries Meijerink and in collaboration with TNO. Currently, I am writing my thesis and I expect to defend my PhD thesis in 2024. More information about my PhD research can be found on this page.