| Titre : | Aqueous synthesis, optical characterization and application of heavy metal-free quantum dots |
| Auteurs : | Matteo Mariani, Auteur ; Finn Purcell-Milton, Promoteur |
| Type de document : | Travail de fin d'études |
| Editeur : | Woluwe-Saint-Lambert : Haute École Léonard de Vinci, 2023 |
| Langues: | Anglais |
| Index. décimale : | TFE - Chimie |
| Descripteurs : |
HE Vinci Nanoparticules ; Semi-conducteurAutres descripteurs photoluminescence |
| Résumé : |
Quantum dots have been intensively studied for several decades due to their promising future: nanoelectronics, photonics, quantum computing, light harvesting, energy conversion, display panel technology, etc. Besides, those nanoparticles have also a huge potential for biomedical applications: biolabeling, bio- and chemosensing, imaging and drug delivery.
Quantum dots (QDs) are semiconductive nanocrystals that show unique tunable properties. In fact, when the size of a bulk semiconductive material is reduced to nanometer dimensions, it begins to show electronic properties that are unique to the nanometer size regime, with properties that are between a molecule and a bulk material and therefore presents unusual properties. Briefly, the smaller the QD, the greater the light energy it absorbs and emits. Hence, there is a simple relation between the size of those nanoparticles and their emission colour: larger QDs manifest a greater wavelength emission than the smaller ones. This simple fact leads to a huge tunability of the spectral properties. Not only the photophysical properties of QDs are influenced by their size but also by a range of other variables, including the shape, the materials and even the ratio of cations that make the QD. It is the band gap of the material that determines at which wavelength the absorption starts. It is also due to quantum confinement that this band gap becomes size dependent, resulting in the increasing of the band gap energy as the size reduces. Besides, it has been found that the presence of a shell (made of another semiconductive material, for example : ZnS) increases the stability and the emission of QDs. To be considered effective, QDs must show a broad absorption and a large absorption coefficient, allowing the QDs to absorb the maximum photons (and of different energies) as possible. Furthermore, QDs must show a wide Stoke’s shift with a narrow emission band and a high quantum yield. The emission band of those particles is correlated with the size distribution: the smaller the size distribution, the narrower the emission band. |
| Accès : | Identifiez-vous avant d'accéder au document électronique |
| Disponible en ligne : | Oui |
| Lieu du stage : | Technological University Dublin (Dublin, Irlande) |
| Département du TFE : | Chimie |
Documents numériques (1)
 TFE - Chimie Adobe Acrobat PDF |
