Supervisor: Dr. Patrick Baesjou
Promotors: Prof. dr. Daniel Vanmaekelbergh and Prof. dr. Alfons van Blaaderen
Funding: marie Curie Actions, ERC
Employed: 1 February 2015 – 31 January 2019

Self-assembly of luminescent nanocrystals into supraparticles

The aim of my research is to self-assemble highly luminescent semiconductor nanocrystals into supraparticles and to study their optical properties.

The self-assembly method that I used has been recently developed in our own institute, and it is based on an oil-in-water microemulsion synthesis [1]: the luminescent nanocrystals dispersed in an apolar solvent phase are put in contact with a  water phase containing surfactants. The mixture is emulsified in a shear cell. As the solvent evaporates, the particles are confined more and more in the spherical droplets, which causes them to finally compact into huge supraparticles.

This newly developed systems are particularly interesting for their optical properties, in particular it has been recently shown that, thanks to the spherical shape and the high difference in refractive index between the nanocrystals and the environment, the light can get trapped inside these structures giving origin to whispering gallery modes [2], which are a good starting point for future applications.

At the moment my research is focused on three different aspects: the first one is assembling nanocrystals of different shape and dimension (e.g. quantum dots, nanorods, nanoplatelets) and then study the morphology of the obtained supraparticles. The second one is assembling nanocrystals emitting at different wavelength in order to realize supraparticle emitting in multiple regions of the visible spectrum [3]. The last one is studying more in depth the optical properties of supraparticles, with an emphasis on whispering gallery modes in order to obtain optical gain and lasing.

Figure 1: left) Typical TEM image of supraparticle. right) Typical luminescent emission of semiconductor nanocrystals under UV light.

[1] B. de Nijs et al. , Nature Mat. 14, 56-60 (2015)

[2] D. Vanmaekelbergh et al. , ACS Nano 9, 3942-3950 (2015)

[3] F. Montanarella et al., ACS Nano 11 (9), 9136–9142 (2017)