Ανακοινώσεις

Υπενθύμιση: Υποτροφίες Κληροδοτήματος Μανασσάκη ακαδ. έτους 2024-25

23 Ιουνίου 2026

Δείτε τη σχετική ανακοίνωση.

Παρουσίαση Πτυχιακής Εργασίας Αποστολία Ραφαέλας Σγαρδώνη

23 Ιουνίου 2026

Ηράκλειο 22 Ιουνίου 2026

 Η ΠΑΡΟΥΣΙΑΣΗ ΠΤΥΧΙΑΚΗΣ ΕΡΓΑΣΙΑΣ

Της φοιτήτριας Αποστολία Ραφαέλας Σγαρδώνη, θα γίνει την

Τετάρτη 24/6/2026 και ώρα 15:00

στην αίθουσα Α3 στο Κτήριο Επιστήμης Υπολογιστών

Θέμα Πτυχιακής:

«Simulations for crystalline polymorphs of ZnO»

Διμελής Επιτροπή:

Ιωάννης Ρεμεδιάκης, Αναπληρωτής Καθηγητής, Τμήμα Επιστήμης και Μηχανικής Υλικών, Πανεπιστήμιο Κρήτης

Γεώργιος Κοπιδάκης, Καθηγητής, Τμήμα Επιστήμης και Μηχανικής Υλικών, Πανεπιστήμιο Κρήτης

Περίληψη:

Zinc oxide (ZnO) is a wide-bandgap semiconductor material that has been extensively studied due to its unique electrical and optical properties, which play a crucial role in various technological applications. In this thesis, first-principles structural simulations are performed using the GPAW computational code, based on Density Functional Theory (DFT), for the comprehensive study of multiple crystal structures of the material. Both the established phases (wurtzite, zincblende, rocksalt) and alternative symmetry structures (CsCl, NiAs, PtS) are examined. For each crystal system, the variation of total energy as a function of lattice volume is calculated, accurately extracting the optimal values for the lattice constants and the Bulk Modulus. Subsequently, the electronic structure is analyzed by calculating the Density of States. The results confirm the semiconducting nature of the lower-pressure structures, while demonstrating a smaller bandgap in the compact, higher-pressure phases.

Call for QuantAlps Postdoctoral Researcher Positions 2027

21 Ιουνίου 2026

PhD call in the Quantum Grenoble Doctoral Programmes

21 Ιουνίου 2026

QuanG and QuanG2 are doctoral programmes dedicated to recruiting and training PhD students in quantum sciences and technologies, hosted in Grenoble, France.

A PhD call is open from 8 June 2026 to 7 September 2026.

See the link for more information.

Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Χριστίνας Σιαϊτανίδου

18 Ιουνίου 2026

Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Χριστίνας Σιαϊτανίδου

Επιβλέπων Καθηγητής: Νικόλαος Πελεκάνος

(Σύμφωνα με το άρθρο 95, παρ. 3 του Ν. 4957/2022, ΦΕΚ 141 τ. Α΄/21.7.2022)

Την Παρασκευή 26 Ιουνίου 2026 και ώρα 11:00 στην Κ206 του Τμήματος Επιστήμης Υπολογιστών του Πανεπιστημίου Κρήτης, θα γίνει η δημόσια παρουσίαση και υποστήριξη της Διδακτορικής Διατριβής της υποψήφιας διδάκτορος του Τμήματος Επιστήμης και Μηχανικής Υλικών κ. Χριστίνας Σιαϊτανίδου, με θέμα:

«MAPbCl₃: a case study of a solution processed semiconductor for efficient ultraviolet optoelectronics»

Περίληψη

In recent years, an extensive research effort has been devoted to hybrid organic-inorganic lead halide perovskites due to their remarkable optoelectronic properties and their potential for a wide range of applications, particularly in photovoltaic devices. Among the members of MAPbX3 family of perovskites, methylammonium lead chloride (MAPbCl₃), the Ultra-Violet (UV) representative, remains relatively unexplored compared to its iodide and bromide counterparts, despite its unique optical characteristics and its potential for optoelectronic applications in the UV. As a result, many of its fundamental optical and electronic properties remain insufficiently understood. The present dissertation focuses on MAPbCl₃ single-crystalline thin films and aspires to contribute to a deeper understanding of the optoelectronic properties of lead-halide perovskites.

To this end, we investigated MAPbCl₃ thin single-crystalline films embedded in a vertical cavity configuration. We observed for the first time dual wavelength lasing at 78K under high power densities, occurring at 414nm and 391nm with distinct lasing thresholds. Within the scope of this observation, thin films were scrutinized under μ-Photoluminescence and μ-Reflectivity measurements in order to understand this unusual behavior. Micro-reflectivity measurements revealed, besides the standard exciton feature at the ∼385nm orthorhombic bandgap, an additional previously unreported excitonic peak at ∼412 nm. This second exciton feature aligns with the second lasing line, strongly suggesting the co-existence of a “second phase” within the primary orthorhombic lattice. We show that this second phase persists up to 300K and is likely associated with the quantum dot-like nanostructures detected on the surface of the MAPbCl₃ crystals. The second phase depends on the growth method and crystal size but is likely traceable in all MAPbCl₃ systems. These insights offer enhanced understanding of the MAPbCl₃ system and open new pathways for blue-UV photonic devices.

In addition, we present a normal-incidence optical method to accurately extract the refractive index dispersion of high-quality MAPbCl₃ single crystals with lateral dimensions of several hundred micrometers. The approach relies on analyzing the spectral positions of Fabry-Pérot modes observed in small-angle micro-reflectivity spectra. Its key enabling feature is the use of angle-resolved micro-reflectivity to directly determine the refractive index at a given wavelength, without prior knowledge of the sample thickness or Fabry-Pérot mode order. The extracted refractive index values are ∼10% higher than previously reported, establishing a new benchmark for MAPbCl₃, which we attribute to the superior crystalline quality of our samples. Upon cooling, the refractive index systematically increases across all crystallographic phases, consistent with a negative thermo-optic effect, except at the tetragonal-to-orthorhombic phase transition at 171K, where it exhibits a discontinuous decrease. The proposed methodology is particularly well suited for micron-sized single crystals in cryogenic environments and can be readily extended to other perovskites and emerging material systems.

As prospective work in this thesis, the formation of ferroelastic domains in the orthorhombic phase of MAPbCl₃ single-crystalline thin films was investigated using polarization-dependent optical measurements. Ferroelastic domains were found to be particularly pronounced in samples grown by the space-confined crystallization method. Upon cooling into the orthorhombic phase, reflectivity measurements revealed a characteristic beating pattern which is absent in the tetragonal phase. This behavior is attributed to the interference of two optical paths arising from the birefringence of the orthorhombic crystal structure. A qualitative estimate yielded a birefringence of Δn≈0.08. Nevertheless, a comprehensive polarization-dependent analysis of the reflectivity spectra is required to quantitatively determine the refractive indices along the principal optical axes and to provide further insight into the coupling between structural symmetry breaking and the optical response of halide perovskites.

In parallel, the ultrafast carrier dynamics of MAPbCl₃ were investigated by time-resolved photoluminescence measurements using a streak-camera. The measurements revealed decay times of several tens of picoseconds, highlighting the strong excitonic character of the material. Furthermore, the main band-edge emission peak exhibited a non-exponential decay curve independent of excitation power, which is accompanied by a redshift, suggesting the presence of a dynamic carrier localization process. Temperature-dependent measurements further showed that the radiative lifetime increases with temperature, as expected for bulk excitonic recombination. At the same time, rapid non-radiative recombination channels were observed. However, the validity of these results should be interpreted with caution, as possible degradation of the perovskite samples during the measurements may have affected the extracted non-radiative lifetimes, requiring further investigation before the optoelectronic potential of MAPbCl₃ can be fully assessed.

Παρουσίαση Πτυχιακής Εργασίας της φοιτήτριας Αδαμαντίας Ράδη

12 Ιουνίου 2026

Η ΠΑΡΟΥΣΙΑΣΗ ΠΤΥΧΙΑΚΗΣ ΕΡΓΑΣΙΑΣ
Της φοιτήτριας Αδαμαντίας Ράδη, θα γίνει την
Παρασκευή 19/6/2026 και ώρα 12:00
στην αίθουσα τηλεκπαίδευσης Ε130 στο Κτήριο Μαθηματικών και Εφαρμοσμένων Μαθηματικών.

Θέμα Πτυχιακής

«Dual-Crosslinked Lignin–CNC Materials via Dynamic Imine Chemistry and Freeze–Thaw Processing as Candidates for Membrane Distillation»

Περίληψη

In this work, bio-based dual-crosslinked polymeric materials were developed from functionalized lignin, cellulose nanocrystals (CNCs), and poly(vinyl alcohol) (PVA) for membrane distillation applications. CNCs served as the primary structural component of the network, providing high crystallinity, mechanical reinforcement, and abundant hydroxyl groups for chemical modification, while PVA was incorporated as a flexible polymer matrix to improve processability, film-forming ability, and mechanical flexibility. Lignin was incorporated as a multifunctional bio-based component, serving as a dynamic covalent crosslinker after amine functionalization and offering potential antibacterial properties. To enable dynamic imine bond formation, CNCs were oxidized to introduce aldehyde groups, while lignin was aminated through a green process to introduce amine groups. The functionalized components were then combined through Schiff base chemistry, forming reversible imine crosslinks. Freeze–thaw processing was also applied to create additional physical crosslinks and improve network stability. A series of dual-crosslinked gels with different lignin contents was prepared to study the effect of lignin concentration on material properties. The gels were characterized through physicochemical, morphological, and rheological analyses to evaluate their structure, crosslinking behavior, viscoelastic properties, gel strength, and recovery ability. Finally, selected formulations were fabricated into porous membranes as candidate materials for membrane distillation applications. The morphology and porous structure of the membranes were characterized using scanning electron microscopy (SEM).

Εξέταση του μαθήματος “ΜΕΤΥ-446 Ηλεκτρονική Μικροσκοπία Διέλευσης”

08 Ιουνίου 2026

Διενέργεια δημόσιας ηλεκτρονικής κλήρωσης για την ανάδειξη των μελών της Εφορευτικής Επιτροπής για τη διαδικασία ανάδειξης εκπροσώπου των μελών Εργαστηριακού Διδακτικού Προσωπικού (Ε.ΔΙ.Π.) του Τμήματος Επιστήμης και Μηχανικής Υλικών, Σχολής Θετικών και Τεχνολογικών Επιστημών του Πανεπιστημίου Κρήτης, και των αναπληρωτών τους, προκειμένου για την συμμετοχή τους στην Συνέλευση Τμήματος, σε εφαρμογή των διατάξεων του ν. 4957/2022 (Α΄141).

02 Ιουνίου 2026

Δείτε τη σχετική ανακοινωση.

ΠΡΟΚΗΡΥΞΗ ΕΙΣΑΓΩΓΗΣ ΠΤΥΧΙΟΥΧΩΝ ΣΤΑ ΠΡΟΓΡΑΜΜAΤΑ ΜΕΤΑΠΤΥΧΙΑΚΩΝ ΣΠΟΥΔΩΝ ΤΟΥ ΤΜ. ΧΗΜΕΙΑΣ ΓΙΑ ΤΟ ΧΕΙΜΕΡΙΝΟ ΕΞΑΜΗΝΟ ΑΚΑΔ. ΕΤΟΥΣ 2026–27

02 Ιουνίου 2026

Σας προωθούμε την προκήρυξη εισαγωγής πτυχιούχων στα προγράμματα μεταπτυχιακών χειμερινού εξαμήνου ακαδ. έτους 2026-27 του Τμήματος μας, με τα συνοδευτικά της έγγραφα για ανάρτηση στα news.

Κατάθεση δικαιολογητικών από 1/6-28/6/2026

Παρακαλούμε δείτε το σχετικό αρχείο: https://news.uoc.gr/news/2026/29-05/files2.zip

Παράταση Ημερομηνίας Εύρεσης Φορέα Πρακτικής Άσκησης Erasmus ως 30-06-2026

02 Ιουνίου 2026

Στο πλαίσιο της Β' Προκήρυξης Κινητικότητας για Σπουδές / Πρακτική Άσκηση Erasmus  (κονδ. 2025) δόθηκε παράταση της ημερομηνίας εύρεσης φορέα Πρακτικής Άσκησης ως 30-06-2026.

Δείτε τη σχετική ανακοίνωση στο https://www.uoc.gr/intrel/students/praktiki/erasmus/prokiryksi-kinitikotitas