• Όνομα εμπλεκόμενου/ης φοιτητή/τριας: Παναγιώτης Κτίστης

• Ημερομηνία εκκίνησης διατριβής: Σεπτέμβριος 2017
• Κατάσταση διατριβής: Σε εξέλιξη

• Phd Student involved: Christos Constantinou

Underwater Robotics have received an increasing interest from research and industry in the last years. Currently, underwater robotics systems are used for various of applications such as pipeline survey, cable maintenance, structures maintenance and inspection. Autonomous underwater robots have to accomplish missions in an unknown and unstructured environment. The mission complexity grows with limited robot sensing systems and limited online communications. For instance, the GPS are not applicable due to the impossibility of underwater electromagnetic transmission. In addition, the vision based system is limited due to poor visibility in deep waters. The actuating system is usually composed of thrusters and control surfaces; all of them have a non-linear dynamics and are strongly affected by the hydrodynamic effects.  The aim is to derive automatic control synthesis and planning strategies to enable underwater vehicles to cooperate and coordinate in carrying out a complex underwater operation.

• Start date: September 2013
• Current Status: Completed December 2019

• Phd Student involved: Marios Constantinou

• Start date: 2012
• Current Status: completed in 2018

• Phd Student involved: Marinos Louka

Pathological conditions, such as inflammation and coagulation in blood cause various health problems and complications. Various biomarkers have been identified and clinical tests have been developed to detect and monitor those conditions. Inflammation and coagulation affect the mechanical properties of blood through different mechanisms, however, both conditions introduce intense changes in the microstructure of the fluid. In this study alterations in the microstructure of blood, as a result of elevated inflammation and coagulation, will be investigated using Digital Data/Image Processing and Electromechanical Characterization techniques. Specialized software packages and electromechanical techniques will be utilised to characterize the aforementioned conditions, with the aim of implementing the developed methods in point-of-care, microfluidics-based applications. The study will focus mainly on blood coagulation whereas inflammation will be studied through the red blood cell aggregation mechanism. 

• Start date: February 2020
• Current Status: on going

• Phd Student involved: Christodoulos Ellinopoulos

The European Green Deal, announced by the European Commission in December 2019, it is a new growth strategy that aims to transform the EU into a fair and prosperous society, with a modern, resource-efficient and competitive economy where there are net emissions of greenhouse gases in 2050 and where economic growth is decoupled from resource use. As part of the European Green Deal, the European Commission proposed raising the EU target by at least 55% by 2030 compared to 1990.To achieve the 55% emission reduction target, by 2030 the EU should reduce drastically the building’s greenhouse gas emissions footprint. It is therefore urgent for the EU to focus on how to make the energy intensive buildings more energy-efficient, sustainable and less carbon-intensive over their full life-cycle. The hotel industry in Cyprus accounts for the highest total energy consumption of all categories in the tertiary sector. In addition, hotel industry is in the first place in production of organic waste. By applying circularity principles in the hotel sector, will increase margins and income, through reduction on energy costs, but mainly will achieve the decoupling of the financial performance and environmental quality of the business. Tourism in Cyprus represents one of the most important economic sectors, with a gross domestic product direct contribution amounting to 12,3% in 2019. Touristic activities have increased in the previous years, with Cyprus having welcomed about 4 million tourists in 2019. The activity growth in the sector results in higher energy demand and consequently, in growing greenhouse gas (GHG) emissions generated by the hotel industry. Some accommodation providers have turned their attention towards GHG emission reduction and sustainability, with enhanced investments in accreditation awards and certification schemes. Despite this progress, tourism accommodations, remain with high potential for GHG emissions reduction.

• Start date: September 2021
• Current Status: Ongoing

• Phd Student involved: Giorgos Constantinou

• Start date: September 2019
• Current Status: on going

• Phd Student involved: Anatoli Tziola

Development of task planning methodologies with applications in the robotization of manufucturing logistics

• Start date: January 2019
• Current Status: on going

• Phd Student involved: Irene Christofi

• Start date: Seotember 2021
• Current Status: On going

• Phd Student involved: Despoina Kokkinidou

The project aims to investigate changes on hemodynamic (e.g. blood pressure and blood flow characteristics) and hemorheological parameters (e.g. sample viscosity, red blood cell (RBC) aggregation, deformability, RBC lysis, etc.) as a result of flow through stented vessels. The study includes in vitro testing as in vivo evaluation in an animal model. Wet lab techniques, hemorheological instrumentation, and innovative in vivo monitoring techniques are utilized to assess how the mechanical behavior and physiology of blood changes due to the stresses developed in the stent area.

• Start date: January 2020
• Current Status: Ongoing

• Phd Student involved: Apostolos Ioakeimidis

Hybrid-perovskite materials are efficient light absorbers, which exhibit high charge carrier mobility and have tunable optoelectronic properties. The excellent physicochemical properties of this material were exploited to build the first reported perovskite sensitized solar cell in 2009 with a power conversion efficiency (PCE) of 3.81%. Within only 5 years the PCE of perovskite solar cells skyrocketed up to 22.1% using mostly solution- and less frequently vacuum- processing techniques. Consequently, perovskite-based solar cells are emerging players in the field of photovoltaics, tackling both the need for low-cost processing and outstanding efficiency. At this point, chemical and thermal stability of these types of solar cells are under intense investigation to rapidly promote their commercialization, hence, realization of precursor materials and methods that will increase the stability and the efficiency is an important goal. The quality of absorber(Perovskite) layer and the implementation of appropriate interfacial layer are of paramount importance to achieve stable and high efficient solar cells. The aim of this study is to investigate the materials and the processes that will promote both the efficiency and the stability of Perovskite solar cells produced by wet methods.

• Start date: January 2017
• Current Status: PhD Viva planned for 23th November 2021

• Phd Student involved: Giannis Antoniou

• Start date: September2019
• Current Status: Ongoing

• Phd Student involved: Fedros Galatopoulos

• Start date: September 2017
• Current Status: on going

• Phd Student involved: Apostolos Ioakimides

• Start date: January 2017
• Current Status: on going

• Phd Student involved: Sergey Pozov

• Start date: September 2016
• Current Status: on going

• Phd Student involved: Efthymios Georgiou

• Start date: September 2013
• Current Status: Completed in 2018

• Phd Student involved: Felix Hermerschmidt

Solution-processed organic and printed electronics, such as organic photovoltaic (OPV) and organic light emitting diode (OLED) technologies, are considered crucial for next generation electronics devices, since they can be fabricated cheaply and upscaled via roll-to-roll processes. OPVs fabricated in this way promise low-cost energy production with short payback times, while OLEDs are already on the market in the form of display applications, however as yet not solution-based. The two technologies are related to one another by the fact that they possess opposing underlying physical processes – OPVs produce electricity from light, whereas OLEDs generate light from electricity.
After an introduction to the field and to the fundamental device principles in chapters 1 and 2, this thesis deals with three key elements in solution-processed organic electronics. Firstly, arguably the most important component of an optoelectronic device, the active layer, is examined in chapter 3. The optical, electrochemical, morphological and transport properties of a series of new small molecules are investigated, which when blended with fullerene acceptors act as electron donors in OPV systems. The best power conversion efficiency is achieved by adding a polydimethylsiloxane additive to the small molecule:fullerene blend, which improves its morphology and doubles the hole mobility.
Secondly, having examined newly-synthesised small molecule active layer materials, in chapter 4 inkjet-printing is introduced as a roll-to-roll compatible technique with which to deposit high-efficiency polymer-based active layers for OPVs. The processing conditions for devices comprising polymer:fullerene blends with the low bandgap conjugated polymers Si-PCPDTBT as well as PCDTBT are presented. By controlling the inkjet printing processing conditions, a significant improvement in device power conversion efficiency is achieved compared to previously reported work using these materials.
And thirdly, having introduced inkjet-printing as a tool for active layer deposition, its use as a tool to generate ITO-free metal nanoparticle electrodes is presented in chapter 5. While previous work has focused on these types of grid structures in OPVs, their novel use in ITO-free OLEDs with a solution-processed architecture based on a conjugated polymer mixture of F8BT and PFO as light-emitting layers is presented. Fine grid lines are achieved and yield solution-processed OLEDs with similar device efficiencies to those based on ITO.

• Start date: 2011
• Current Status: completed in 2015

• Phd Student involved: Achilleas Savva

Solution based organic photovoltaics (OPVs) are considered one of the most promising future photovoltaic technologies for low-cost solar energy production. Attractive features of OPVs are the possibilities for thin flexible devices which can be fabricated using high throughput roll-to-roll process, resulting in a shorter energetic pay-back time. Most of the scientific literature in the field of OPVs is focused on the fundamental science, the materials properties as well as device physics. These disciplines are essential to continue driving the OPV technology towards high performance. This thesis initially addresses the basic state-of-the-art technologies around the OPVs science, going through the basic principles of OPVs, device architecture concepts, manufacturing technologies, material choices, electrical characterization methods and OPV device degradation mechanisms. In chapter 2, the origin of the improvement of the power conversion efficiency (PCE) of inverted OPVs when an interfacial insulating layer of PTE is introduced between ITO and TiOx bottom electrode, is studied. Using a series of measurements the interaction at the interfaces within the ITO/TiOx and ITO/PTE/TiOx is analyzed and correlated to observations based on device physics analysis. Based on our findings, we suggest that the altered morphology in combination with the difference in hydrophilicity of the PTE modified TiOx affects device performance either by increasing the carrier selectivity of the TiOx layer or by causing enhanced vertical phase segregation of the P3HT:PCBM layer. Within chapter 3, through detailed device physics analysis PEDOT:PSS PH is proposed as most suitable hole selective contact for inverted OPVs. By understanding the synergetic effects of PEDOT:PSS wetting agents on the hole selectivity of inverted OPVs we demonstrate a novel combination of PEDOT:PSS additives mixture, as an effective route to further increase the device performance and reliability of inverted OPVs. Finally, within chapter 4 it is shown that solution processed doped metal oxides charge carrier selective contacts, could be proven beneficial concerning product development targets of inverted OPVs. Using carefully designed solution process methods novel n- and p- doped metal oxides are introduced as charge carrier selective contacts in inverted OPVs exhibiting exceptional optoelectronic properties and functionality within the inverted structured PVs, as analyzed by a series of measurements and extensive device physics analysis.

• Start date: 2011
• Current Status: completed in 2014

• Phd Student involved: Marios Neophytou

attention over the last few years. New fields of applications are feasible as OPVs are
lightweight, flexible and have the potential for truly low fabrication cost. At present,
so-called bulk heterojunction structures based on blends of a conjugated polymer as
electron donor and a soluble fullerene derivative as acceptor represent the OPV
material system with the highest power conversion efficiency reported until now.
This thesis addresses several critical parameters in the processing issues of
polymer:fullerene based organic solar cells. Primarily, a sedulous investigation
concerning deposition parameters of an electron blocking-hole transporting interfacial
layer (Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) [PEDOT:PSS]) was
performed. The conductivity and thickness effect of the layer on overall device
performance was analyzed. Then the optically active layer consisting of the reference
poly-3-hexylthiophene and phenyl-C61-butyric acid methyl ester (P3HT:PCBM)
blend material system was investigated. Parameters such as composition ratio, layer
thickness and annealing conditions were examined in order to achieve the reference
organic solar cells for the newly founded Molecular Electronics and Photonics
research unit with optimized and highly reproducible power conversion efficiency
(PCE).

The processing steps described in this thesis yielded P3HT:PCBM devices
with repeatable and consistent PCE performance higher than 3 % and now the process
is used as a standard method to provide the reference solar cells in the Molecular
Electronics and Photonics laboratory. During the processing steps of P3HT:PCBM, a
21 kink in the shape of the current density/voltage (J/V) characteristics was observed.
Devices of different ratios of P3HT to PCBM were fabricated and sent for further
studies at the Jaume University in Spain. The s-shaped characteristics were explained
by capacitance measurements related to the presence of defect bands exhibiting
Gaussian shape located at E approximate to 0.38 eV above the highest occupied
molecular orbital level of the P3HT.
After establishing the reference process for P3HT:PCBM based solar cells new
synthesized conjugated polymers donors were investigated in terms of their potential
for organic solar cell applications. A perfluoro poly[(9,9-dioctylfluorenyl-2,7-diyl)-
alt-5,5- (4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)] (APFO-3) derivative and
different fluorescent boron-dipyrromethene conjugated polymers (BODIPY) were
characterized. Absorption and photo luminescent spectra as well as current density
characteristics of the fabricated photovoltaic devices were compared to commercially
available materials. Despite the exhibited low mobility and PCE values (in the range
of 0.2-1.2 %), some of the newly synthesized polymers, like PBT and PBTT, are
promising electron donors for further synthetic trials due to their high absorption
coefficient and high photovoltage (over 1 V).
Furthermore a systematic study of inkjet printing processing parameters for
organic solar cells applications was followed. Optimum parameters for inkjet printing
active layer were firstly identified, proving that the viscosity of the inkjet formulation,
substrate temperature, drop spacing and the height of the droplet in relation to the
surface are critical factors to achieving high quality inkjet-printed polymer-fullerene
22 based active layers. The last part of the chapter focuses on replacing the expensive
and brittle indium tin oxide (ITO) with an inkjet printed silver grid architecture.
Investigation of an inkjet-printed silver nanoparticle grid combined with different
conductivity PEDOT:PSS was performed. An ultimate control of the design
requirements of current collecting grid based on the proposed inkjet-printed process to
accurately control the uniformity and dimensions of the silver nanoparticle based grid
was achieved. The performed measurements revealed higher transparency of the
printed Ag grid when compared to different thicknesses of ITO. As a result a record
power conversion efficiency of 1.96 % is achieved for ITO-free P3HT:PCBM based
organic solar cells using the combination of PEDOT:PSS/inkjet printed nanoparticles
based current collecting grids.

• Start date: 2008
• Current Status: completed in 2012

• Phd Student involved: Christos Constantinou

• Start date: September 2013
• Current Status: On going

• Phd Student involved: Dimitris Pasias

• Start date: January 2017
• Current Status: On going

• Phd Student involved: Marios Constantinou

• Start date: January 2012
• Current Status: On going

• Phd Student involved: Demetris Photiou

• Start date: January 2014
• Current Status: Completed September 2019

• Phd Student involved: Rafaela Agathokleous

• Start date: January 2014
• Current Status: Completed November 2017