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Study of electrical and dielectric properties of ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor thesis is focused on the study of electrical and dielectric properties of ionic liquids. Two types of OECT substrates with different semiconductor channel lengths made of PEDOT:PSS were used to measure these properties. The dielectric properties were measured by impedance spectroscopy, where the dependence of the impedance value and its phase angle on the voltage frequency was measured. It was found from V-A characteristics, that the best closing of semiconductor layer occurs at a positive UGD voltage. The switching speeds of different ionic liquids were compared for this voltage.
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Study of transistor properties with ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This diploma thesis is focused on the study of electric and dielectric properties of transistors based on ionic liquids. The measurements were performed on organic electrochemical transistors with a semiconducting channel made of PEDOT:PSS, which were firstly prepared on ITO substrates, later they were printed using 3D print. Ionic liquid NO4 (1-butyl-3-methylimidazolium hydrogensulfate) was used for measuring of the properties. Electrical properties were determined by measuring volt-ampere characteristics, dielectric properties were measured by impedance spectroscopy.
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Study of ion liquids transistor properties
Maráčková, Lucie ; Nešpůrek, Stanislav (referee) ; Sládek, Petr (referee) ; Zmeškal, Oldřich (advisor)
The doctoral thesis is focused on ionic liquids, electrochemical transistors and the study of their electrical and dielectric properties. Current-voltage characteristics were used for determination of the electrical properties of measured ionic liquids. Impedance spectroscopy was used to determine the dielectric properties of measured ionic liquids. Transient measurement was used to determine the electrical properties of measured organic electrochemical transistors based on ionic liquids. Models of every measured ionic liquid was assembled from current-voltage characteristic and from impedance spectroscopy. Models of every measured organic electrochemical based on ionic liquids was assembled from transient measurement.
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Gel Polymer Electrolytes for Electrochemical Power Sources
Jahn, Michal ; Bartušek, Karel (referee) ; Paidar,, Martin (referee) ; Sedlaříková, Marie (advisor)
Dissertation thesis is focused on study of gel polymer electrolytes for electrochemical power sources, but also for other application. The electrical, electrochemical, mechanical and optical properties of gel electrolyte samples were measured in this work. The main goal was to prepare samples with high specific conductivity and with largest possible potential windows. Thermal stability of some samples was also monitored using thermogravimetric analyzes. The optimization of the chemical composition, quantities and ratios of individual chemicals has been made. Comparison of thermal polymerization and UV polymerization was performed. In the first part of the work, aprotic solvents and their mixtures in combination with lithium and sodium salts and one ammonium salt were investigated. Another subject of research was various crosslinking agents with methacrylate-based monomers. The second part of the work investigated the effect of ionic liquids, phosphor base flame retardants and nanoparticles as additives to gel electrolytes. In the last part of the work, the influence of the magnetic and electric field on the polymerization of gel electrolytes containing nanoparticles and selected copolymers was studied. Finally, a Li-ion cell with a graphite anode, LiFePO4 cathode and selected gel electrolyte was assembled.
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Study of transistor properties with ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This diploma thesis is focused on the study of electric and dielectric properties of transistors based on ionic liquids. The measurements were performed on organic electrochemical transistors with a semiconducting channel made of PEDOT:PSS, which were firstly prepared on ITO substrates, later they were printed using 3D print. Ionic liquid NO4 (1-butyl-3-methylimidazolium hydrogensulfate) was used for measuring of the properties. Electrical properties were determined by measuring volt-ampere characteristics, dielectric properties were measured by impedance spectroscopy.
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Gel Polymer Electrolytes Based On MMA With Ionic Liquids
Jahn, Michal
Gel polymer electrolytes are perspective electrolytes for new types of Li-ion batteries today. The properties respectively advantages of these gels can be used also in other fields of electrochemistry. Very promising combination can be electrochemically stable polymers and ionic liquids, which are substances that consist of an organic cation and an inorganic or organic anion, with a melting point below 100 °C. Main advantages of ionic liquids are high ionic conductivity, inflammability and excellent electrochemical stability. These ionic liquids may be suitable for new lithiumion batteries and supercapacitors, especially where the required higher thermal stability. In this paper, I will present fundamental characteristics of gel polymer electrolytes with ionic liquids.
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Study of Electric and Dielectric Properties of Ionic Liquids
Altšmíd, Jakub ; Boušek, Jaroslav (referee) ; Mikula, Milan (referee) ; Nešpůrek, Stanislav (advisor)
Dizertační práce je zaměřena na studium elektrických a dielektrických vlastností iontových kapalin. Iontové kapaliny mohou nacházet uplatnění v široké škále aplikací, především pak v elektrotechnice. Teoretická část se věnuje popisu základních vlastností iontových kapalin a možností jejich uplatnění v kondenzátorech a elektrochemických senzorech plynů. Experimentální část se věnuje použitým metodám charakterizace vlastností iontových kapalin, jsou zde popsány teoretické poznatky o dielektrické spektroskopii včetně metod stanovení fyzikálních vlastností a vyhodnocení experimentálních dat. Experimentální část je rozdělena na dvě základní části. První se věnuje studiu iontových kapalin pro použití jako elektrolytu v kondenzátorech, druhá část se věnuje studiu vlastností připravených experimentálních senzorů na NO2, zejména vlivem vlastností iontových kapalin na sledované parametry senzoru.
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Study of electrical and dielectric properties of ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor thesis is focused on the study of electrical and dielectric properties of ionic liquids. Two types of OECT substrates with different semiconductor channel lengths made of PEDOT:PSS were used to measure these properties. The dielectric properties were measured by impedance spectroscopy, where the dependence of the impedance value and its phase angle on the voltage frequency was measured. It was found from V-A characteristics, that the best closing of semiconductor layer occurs at a positive UGD voltage. The switching speeds of different ionic liquids were compared for this voltage.
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