Friday Materials Science Colloquia (#9)

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Seminari

Nell'ambito del ciclo "Friday Materials Science Colloquia" venerdì 30 Giugno 2023 alle ore 12.00 presso l’Aula Seminari, Piano I, Edificio U5 – via Roberto Cozzi 55 si terranno i seguenti seminari:

Relatrice: Dott.ssa Silvia Mostoni
Titolo: Surface modification of metal oxide nanoparticles for hybrid composite materials

Abstract: In the recent years, metal oxide nanoparticles (NPs) have gained an increasing interest because of their unique size dependent properties, with applications in a wide range of technologies such as (photo)catalysis, energy storage, optics, packaging, and automotive. Their high versatility is connected to the possibility to modulate their morphological and structural features, as well as their surface properties, by tailoring the inorganic/organic interfaces of oxide materials. Soft-chemistry techniques are used as powerful approaches to synthesize morphology-controlled oxide NPs and provide them with specific surface functionalities, through soft templates, capping molecules and by the careful use of controlled synthetic conditions. This plays a crucial role especially in the development of advanced hybrid materials and in the preparation of novel polymer nanocomposites, leading to the generation of active components in many formulation products and composite materials.
In this context, the work herein presented shows the design of new hybrid inorganic/organic architectures mainly based on silica and/or zinc oxide NPs, aiming at imparting functional properties to the metal oxide NPs by exploiting different functionalizing strategies. Specifically, three main targeted applications will be considered to demonstrate the key role of surface engineering and materials design in the development of inorganic-based materials, moving from the development of new activators for elastomer vulcanization [1], functional hybrid fillers [2] and luminescent inorganic materials with controlled optical properties [3]. Having the synthesis and characterization of these materials as the main core of the topic, also the performances of the materials will be discussed for each application, with a particular attention to investigate the correlation between the materials reactivity and their structural and morphological properties. The further optimization of the materials synthesis and functional properties is currently ongoing, promoted by the challenging opportunities to match the advances in the research of new technologies and their potential large-scale applications.

References:
[1] S. Mostoni et al., Ind. Eng. Chem. Res. 60, 10180-10192 (2021)
[2] L. Mezzomo et al., Electrochimica Acta 411, 140060 (2022)
[3] R. Crapanzano et al., Phys. Chem. Chem. Phys. 24, 21198-21209 (2022)
[4] S. Mostoni et al., Composites Science and Technology 230, 109780 (2022)

 

Relatore: Dott. Artur Tuktamyshev
Titolo: Droplet Epitaxy of Nanostructures for Non-Classical Emitters

Abstract: A new growth method for III-V microcrystals was first proposed by N. Koguchi and co-workers in the 1990s [1]. The fabrication process consists of two stages. Group III liquid metal droplets are grown on the surface, followed by crystallization and transformation into semiconductor nanostructures by annealing in the group V atmosphere.
The main advantages of DE are the possibility to fabricate semiconductor quantum dots (QDs) in lattice-matched systems, for instance, GaAs/AlGaAs QDs [2], compared to common growth technique for strain-driven QD fabrication – the Stranski-Krastanov growth mode, at which 3D islands of the growth material appear on the substrate surface with different lattice constant due to elastic strain relaxation. The second is the independent control of the density and the size of self-assembled nanostructures.
I would like to present a critical survey of the state of the art of DE, highlighting the advantages and weaknesses, the achievements and challenges that are still open, in view of applications in quantum photonic devices. DE has proven its ability to produce high-performance low-density QD-based non-classical emitters (single and entangled-photon sources) [3, 4].

References:
[1] Koguchi, N., Takahashi, S. & Chikyow, T. New MBE growth method for InSb quantum well boxes. J. Cryst. Growth 111, 688–692 (1991).
[2] Bietti, S. et al. Precise shape engineering of epitaxial quantum dots by growth kinetics. Phys. Rev. B 92, 075425 (2015).
[3] Schweickert, L. et al. On-demand generation of background-free single photons from a solid-state source. Appl. Phys. Lett. 112, 093106 (2018).
[3] Basso Basset, F. et al. High-Yield Fabrication of Entangled Photon Emitters for Hybrid Quantum Networking Using High-Temperature Droplet Epitaxy. Nano Lett. 18, 505–512 (2018).

 

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