Hybrid nanomaterials for novel photonic devices

Abstract

This PhD thesis investigates the optical properties of colloidal semiconductor nanocrystals and evaluates concepts regarding the development of novel photonic devices. Spectroscopic studies of the exciton dynamics in colloidal lead sulfide (PbS) quantum dots (QDs) by tuning the temperature are presented. The lowest exciton splitting for a range of PbS QDs sizes is calculated and a transfer of the oscillator strength from dark to bright states as the size increases is demonstrated. Hybrid structures with PbS QDs deposited on silicon substrates were also studied in order to explore whether excitons can be created in this material by means of resonant energy transfer.

Furthermore, elongated asymmetric cadmium selenide/cadmium sulfide (CdSe/CdS) quantum rods are used as gain medium for the development of whispering gallery mode microlasers. Single-mode operation of hybrid lasers based on colloidal CdSe/CdS core/shell QRs in silica microspheres is for the first time reported. Laser-emission tunability over a range of 2.1 nm is also demonstrated, by heating the microsphere cavity with a 3.5 µm laser.

In the last part of this thesis, unstructured and micro structured LiNbO₃ are presented as excellent substrates for cell culture. Two commonly used neuron-like cells have been successfully proliferated and differentiated on both polar (±z) faces of LiNbO₃ crystal substrates. Spatially selective attachment of neuron-like cells onto the domain engineered micro-structured substrates is also shown, providing the opportunity for the development of functional materials for the study of neuronal networks.

More information

Identifiers

ORCID for P.G. Lagoudakis: orcid.org/0000-0002-3557-5299

Catalogue record

Export record