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Technical reports	[13]	Publications	[18]
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Identifier

000444738

Title

Fabricating new perovskite morphologies and anchoring them on functional substrates

Alternative Title

Δημιουργία νέων περοβσκιτικών μορφολογιών και πρόσδεση αυτών σε λειτουργικά υποστρώματα

Author

Κιοκεκλή, Σερπίλ

Thesis advisor

Κιοσέογλου, Γεώργιος
Στρατάκης, Εμμανουήλ
Στούμπος, Κωνσταντίνος

Abstract

In the past few years, metal halide perovskite nanocrystals have emerged due to their exceptional optical properties. The most attractive trait of these materials is the properties tunability by composition, shape or size alterations. The synthesis of highly anisotropic nanocrystals is even more promising, as strong quantum confinement imposed by one (nanorods/nanowires) or two (nanoplatelets) dimensions give rise to higher exciton binding energy and narrow emission linewidth, which are of great importance in LEDs and lasing. Nevertheless, complications concerning the ultra-thin metal halide nanocrystals are governed by instability towards environmental conditions (light and moisture) and susceptibility to aggregate and/or breaking down. Notably, the aim of this project was oriented towards the investigation of a reproducible protocol, and thus, the second part of the initial project title could not be achieved. Α facile, ambient-conditions chemical protocol is presented to obtain uniform and ultra-small 2D CsPbBr3 nanoplatelets, here called nanorods due to their size and morphology. The synthesis is based on the ligand-assisted precipitation method, by combining low reaction temperature, dilution and ambient light to control the growth of the thin nanocrystals. No complex chemistry apparatus or inert gas flow are needed. Τhe nanorods are homogeneous in size, with 7.8±1.4 nm length and 2.7±0.5 nm width, which corresponds to three monolayers. The nanorod colloidal solution is strong PL active emitting in blue spectral region indicating strong quantum confinement effects, as their width is below the Bohr radius reported for this material. These ultra-thin quantum-confined nanorods are among the thinnest in the literature and could be promising candidate in making efficient LEDs. Furthermore, this cost-effective colloidal method by careful regulation of the three important parameters (temperature, dilution, exposure time to light) can be used for the fabrication of other 2D nanocrystals.

Language

English

Subject

Nanocrystals

Νανοκρυστάλλοι

Νανοπλακίδια

Νανοράβδοι

Issue date

2022-03-18

Collection

School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses

Type of Work