Πλοήγηση ανά Συγγραφέας "Kymakis, Emmanouil"

Τώρα δείχνει 1 - 4 of 4
  • Μικρογραφία εικόνας
    Τεκμήριο
    Design, fabrication and characterization of efficient solution processed organic–inorganic hybrid perovskite solar cells.
    (ΕΛΜΕΠΑ, Σχολή Μηχανικών (ΣΜΗΧ), ΔΠΜΣ Νανοτεχνολογία για Ενεργειακές Εφαρμογές, 2024-10-30) Tzoganakis, Nikolaos; Τζογανάκης, Νικόλαος; Kymakis, Emmanouil; Κυμάκης, Εμμανουήλ
    Developing countries and emerging markets demands for environmental friendly renewable energy sources continuously increases. Renewable energy technology and especially photovoltaics is an alternative solution that gains ground year after year to replace the established carbon consuming energy production methods. One of the latest and of high potential photovoltaics’ generation technology is the so-called perovskite solar cells (PeSCs). A PeSC consists of a laminated structure, which is being developed layer by layer using facile deposition methods onto rigid and flexible substrates. Organic-inorganic hybrid perovskite is a material with the crystal structure AMX3, where A is the organic part, M is the metal and X stands for a halide ion. Since 2009 when the first application of organohalide lead perovskite as the light harvester in solar cells was reported1 , tremendous attention has been devoted to these new types of perovskite-based solid-state solar cells and remarkable power conversion efficiency of over 24% has been achieved up to date. With respect to its hybrid nature, the material is endowed with high carrier mobility and absorption coefficient, relatively long diffusion lengths and low temperature processing, that renders it ideal for optoelectronic applications. During the implementation of this thesis, the mixed two perovskites CsMAFA, RbCsMAFA were synthesized and applied as light harvesting material in planar inverted PSCs. In our case the hybrid perovskite semiconductor selected, was deposited using the spin coating deposition technique on top of glass/ITO/ PTAA substrate and after that the deposition of an electron transport material followed. To complete the device, thermal evaporation was used to form the silver counter electrode. A variety of factors (annealing temperature of the perovskite, morphology, and additives to perovskite ) that play a critical role towards the achievement of high and stable power conversion efficiencies (PCEs) were studied and applied.
  • Μικρογραφία εικόνας
    Τεκμήριο
    Printed strain sensors for wearables and Iot.
    (ΕΛΜΕΠΑ, Σχολή Μηχανικών (ΣΜΗΧ), ΔΠΜΣ Νανοτεχνολογία για Ενεργειακές Εφαρμογές, 2024-10-30) Papastefanakis, Dimitrios; Παπαστεφανάκης, Δημήτριος; Kymakis, Emmanouil; Κυμάκης, Εμμανουήλ
    The Internet of Things (IoT) and wearable technology blend represents a transformative synergy in tech. This work kicks off by outlining IoT fundamentals and unique traits of wearables. A deep dive into IoT-enabled wearable hardware explores sensors, microcontrollers, connectivity, batteries, and interfaces. The focus shifts to strain sensors, detailing classifications (resistive, capacitive, optical), fabrication methods like 3D printing, and materials, mechanisms, and design considerations. Applications cross over healthcare, sports, gaming, robotics, and more. The experimental setup is presented in detail, featuring commercial sensors, electronic interfaces (op-amp, voltage divider), and data processing tools (Python, NumPy, Pandas, Matplotlib). Integration through Wi-Fi connection with IoT platforms like ThingSpeak and Blynk, using ESP8266, is explored. The conclusion highlights sensor output, online monitoring, analysis, and automation. It wraps up with conclusive remarks and future research avenues.
  • Μικρογραφία εικόνας
    Τεκμήριο
    Spray system prototype for thin-film coatings upcycling an inkjet printer.
    (ΕΛΜΕΠΑ, Σχολή Μηχανικών (ΣΜΗΧ), ΔΠΜΣ Νανοτεχνολογία για Ενεργειακές Εφαρμογές, 2024-11-01) Veisakis, Georgios; Βεϊσάκης, Γεώργιος; Kymakis, Emmanouil; Κυμάκης, Εμμανουήλ
    This work presents a spray system prototype, which was made for the needs of thin-film coatings fabrication. It is based on a common airbrush and parts of an old broken inkjet printer. Transforming creatively waste or useless materials to something new is called upcycling. It is an inalienable part of the green economy, a philosophy a few industries have already followed. Upcycling an inkjet printer to create a low-cost prototype machine is proof that a low carbon footprint can be achieved in many ways and not only by recycling the increasing waste. We can reduce waste, and engineers following this philosophy can also develop their creativity. In addition, were chosen to be presented three representative experiments executed using the spray system prototype. The first experiment is a fabrication of a transparent flexible electrode using silver nanowires and graphene. The second experiment is an alternative fabrication of a Hole Transport Layer (HTL) for a perovskite photovoltaic structure. And the last one is a two-step fabrication of a flexible conductive electrode using graphene oxide and then converting it to reduced graphene oxide. Finally, it is also presented the fabrication and characterization equipment.
  • Μικρογραφία εικόνας
    Τεκμήριο
    Αναδυόμενες τεχνολογίες παραγωγής ενέργειας χρησιμοποιώντας δισδιάστατα νανοϋλικά.
    (ΕΛΜΕΠΑ, Σχολή Μηχανικών (ΣΜΗΧ), ΔΠΜΣ Νανοτεχνολογία για Ενεργειακές Εφαρμογές, 2024-10-29) Λέκκας, Γεώργιος; Lekkas, Georgios; Κυμάκης, Εμμανουήλ; Kymakis, Emmanouil
    Η Nανοτεχνολογία είναι από τα πιο καινοτόμα πεδία εφαρμογής της μηχανικής αφού οι δομές που χρησιμοποιεί είναι τόσο μικρές που συχνά έχουν το μέγεθος ενός μορίου και μελετώνται και οι ακόμη πιο μικρές που μπορεί να έχουν το μέγεθος ενός ατόμου. Επίσης εμφανίζουν ιδιότητες οι οποίες είναι τελείως διαφορετικές από τις μέχρι τώρα συνηθισμένες μακροσκοπικές εφαρμογές καθώς είναι κβαντικής φύσης. Ακριβώς λόγω των ιδιοτήτων και του μεγέθους τους επιχειρείται η χρησιμοποίηση τους σε πολλαπλές επιλογές και εφαρμογές ανάμεσα στις οποίες είναι και η ενέργεια. Χαρακτηριστικό είναι ότι τα τελευταία χρόνια έχει χρησιμοποιηθεί σε καινοτόμες μεθόδους παραγωγής ενέργειας όπως είναι η ενέργεια από νερό ,η ηλιακή ενέργεια , η μηχανική ενέργεια καθώς και άλλες ποικίλες μορφές ενέργειας.