National Repository of Grey Literature 34 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Advanced materials for organic bioelectronics
Sedlák, Jiří ; Salyk, Ota (referee) ; Weiter, Martin (advisor)
This bachelor thesis deals with the research of PEDOT:DBSA material for possible use in organic bioelectronics. First, a method for preparing PEDOT:DBSA layers of required thickness was standardized and the dependence of the thickness on the conductivity of the material was monitored. Subsequently, the effect of thermal stabilization and EG, DMSO and H2SO4 substances on the conductivity of prepared layers was tested. Two principles were tested to increase conductivity. The first was the principle of adding substances as dopands into liquid polymeric solutions. The second method of sample preparation was the method of secondary treatment of already prepared layers of pure PEDOT:DBSA. All of prepared polymeric layers were characterize by two methods: four point probe and profilometry.
New organic semiconductors for bioelectronics
Malečková, Romana ; Salyk, Ota (referee) ; Vala, Martin (advisor)
This thesis focuses on the characterization of PEDOT:DBSA, a new semiconducting polymer for use in bioelectronic devices. It also deals with possibilities of surface treatment in order to enhance its biocompatibility and stability in aqueous environments. For this purpose, the organic polymer films were crosslinked with two crosslinking agents – GOPS and DVS. The ability of these agents to prevent leaching of some fractions of the polymer films in an aqueous environment and the ability to bind polymer molecules to each other as well as to the glass substrate was studied using the delamination test. Subsequently, the effects of these crosslinking agents on the film properties essential for the proper functions of bioelectronics made of these materials, was studied by contact angle measurements and four-point probes respectively. Moreover, several OECTs were prepared using original and crosslinked material as an active layer and were characterized by measuring transconductance and volumetric capacitance. PEDOT:DBSA has been shown to be a suitable material for use in bioelectronics, but its thin layers need to be stabilized in an aqueous environment. The agent DVS appears to be unsuitable for this purpose, mainly due to its insufficient film stabilization and its increased hydrophilicity of the film surface, thus increased tendency to interact with water, resulting in degradation of these thin layers. In contrast, GOPS, despite some reduction in film conductivity, has been able to stabilize the polymer layer over the long term, and thus appears to be a suitable way to stabilize PEDOT:DBSA.
Printed Biosensor Based on Organic Electrochemical Transistor
Omasta, Lukáš ; Mikula, Milan (referee) ; Boušek, Jaroslav (referee) ; Salyk, Ota (advisor)
Organické elektronické zariadenia sú vyvíjané ako vhodné riešenia senzorov pre bioelektroniku, a to najmä kvôli dobrej biokompatibilite organických polovodičov v nich použitých. Takzvané biosenzory dokážu premeniť elektrochemické procesy na elektronický signál. Matrica takýchto biosenzorov môže simultánne skenovať množstvo biologických vzoriek, alebo rôznych tkanív v živých systémoch. Aktívnou súčasťou zariadenia je organický elektrochemický tranzistor (OECT). V tejto práci je diskutovaný teoretický rámec fungovania takéhoto zariadenia, jeho elektrická charakterizácia, aplikácia v biosenzoroch na báze buniek, spôsoby výroby a aktuálnym stavom techniky v oblasti organickej elektroniky. Experimentálna časť obsahuje konkrétne výrobné postupy vývoja OECT zariadení, ktoré boli použité v našom laboratóriu. Hlavný dôraz sa kladie na schopnosť vyrobených zariadení detekovať reakciu a monitorovať stimuláciu elektrogenných buniek. Za týmto účelom boli vyvinuté matice mikroelektródových OECT zariadení založených na polovodivom polyméri PEDOT:PSS. Tieto boli vyrobené s využitím bežnými tlačiarenských techník (atramentová tlač a sieťotlač) spolu so štandardnými litografickými postupmi. Najnovšie nami vyvinuté zariadenia dosahujú najväčšieho zosílením signálu, g = 2,5 mS a časovú konštantu t = 0,15 s. Tieto zariadenia sú porovnateľné, často dokonca lepšie ako niektoré iné najmodernejšie a plne litograficky pripravené senzory.
Microelectrode arrays for mioelectronic
Bráblíková, Aneta ; Vala, Martin (referee) ; Salyk, Ota (advisor)
Organic electronic biosensors are developed as suitable devices that can transform electrochemical processes within the cell membrane into an electronic signal and enable to measure electrical activity of excitable cells and tissues both in vitro and in vivo and thus represent valuable alternative to current cell monitoring methods. In this work we focus on the fabrication of electrophysiological sensors based on organic semiconductors printed by the material printing method. Microelectrode arrays (MEAs) are active components of the device, which can monitore cellular activity and above that stimulating cells with electrical pulses. The proposed platform should be used for cytotoxicity of potential drugs especially on cardiac cells (cardiomyocytes). The experimental part focus on specific production processes of platforms, which were prepared in the laboraty with emphasis on biocompatibility and conductivity of device.
Preparation and characterization of perovskite solar cells
Juřík, Karel ; Salyk, Ota (referee) ; Pospíšil, Jan (advisor)
This work deals with the perovskite photovoltaic cells. The first part summarises the basic information about this technology and shows the most important milestones in its development. Following part includes the parameters required to characterise the electric properties of a photovoltaic cell and the assessment of its quality. The experimental part of this thesis aims to describe the influence of the annealing time of the perovskite active layer on the final efficiency of created solar cells. The best results were determined to be achieved with the annealing time of 90 minutes.
Generation of ozone by photochemical processes in CO2
Kucserová, Aneta ; Salyk, Ota (referee) ; Mazánková, Věra (advisor)
The bachelor thesis deals with the measurement of ozone concentration, which was produced by dielectric barrier discharge, corona discharge and UV lamp. The concentration of ozone in the air was also measured. The theoretical part deals with the basic properties of ozone, its use and determination of concentration by various methods. In the experimental part, ozone generation is described by the above-mentioned discharges.
Modelling of bioelectronic devices
Truksa, Jan ; Vala, Martin (referee) ; Salyk, Ota (advisor)
Tématem této práce je počítačové modelování organického elektrochemického tranzistoru (OECT). Pro vytvoření modelu bylo třeba vypočítat rozložení elektrického pole a koncentrace iontů elektrolytu. Výpočet byl proveden numericky pomocí metody konečných prvků. Bylo vypočítáno rozložení elektrického potenciálu na povrchu kanálu OECT, dále byly vypočítány změny vodivosti a výstupní proud OECT. Výpočty byly provedeny na osobním počítači pomocí komerčního softwaru COMSOL Multiphysics. Kvůli nedostatečnému výpočetnímu výkonu musel být model rozdělen na části a drasticky zjednodušen. Prezentované výsledky se liší od literatury, protože se nepodařilo správně modelovat saturaci tranzistoru. Odchylky od reálného chování OECT jsou pravděpodobně způsobeny zjednodušením modelu.
Optimization of printing of organic electronic devices printing for bioelectronics
Bráblíková, Aneta ; Hrabal, Michal (referee) ; Salyk, Ota (advisor)
This bachelor thesis is focused on optimization of printing of organic electronic devices printing for bioelectronics. The main goal of this bachelor thesis is a series of experiments devised to optimize semiconductive structures of PEDOT (semiconductive polymer) and description of the process used in the preparation of organic electrochemical transistors for biosensor by screen printing technology. The research focused on application of bioelectronics, printing technologies, conductive inks suitable for the preparation of OECTs (organic electrochemical tranzistors) and rheological properties of materials. Main conditions tested in the experimental part were temperature, stirring and additon of DMSO (dimethylsulfoxide) into a printing pasted. The evaluated parameters of materials were basic viscoelastic characteristics. At the ent of the thesis have been successfully designed the series of transistors to monitor cell cultures.
Optimalization of printing methods of organic semiconducting layers preparation
Ehlich, Jiří ; Vala, Martin (referee) ; Salyk, Ota (advisor)
Electrophysiological biosensors enables a novel way to measure electrical activity of biological structures both in-vitro and in-vivo and represents valuable alternative to current cellular activity measuring methods. Within this work we will be focusing on development of organic semiconductor (PEDOT:PSS) based Organic Electrochemical Transistors (OECTs) and optimization of material printing methods used in their development. These transistors are meant to be able to transfer electrochemical signals within the cell membrane to electrical signal. Such sensors should be used for cytotoxicity testing of chemicals and potential drugs on cardiomyocytes. Main benefits of OECTs are in their higher sensitivity thanks to their ability to locally amplify electric signals, better noise-signal ratio and outstanding biocompatibility. Their development is undemanding and inexpensive due material printing methods and materials processable at room temperatures.
Modelling of organic electrochemical transistors
Truksa, Jan ; Omasta, Lukáš (referee) ; Salyk, Ota (advisor)
The topic of this work is the making of a virtual model of a circular organic electrochemical transistor (OECT) and its electric field, and comparison of the computed results to a real system of rotationally symmetrical electrodes. The electric potential field in the transistor was modelled using the finite element method and the electric field and current field were determined using the results. Later, the electric potential field was mapped in a real system of aluminium electrodes, submerged in water. The electric field model of an unusually configured circular OECT is presented in this work. Due to insufficient computing capacity, the model had to be significantly simplified. The computed results agree with the experimentally determined potential field despite the simplification. The deviations of the model output characteristic from real OECT characteristic were caused by simplifying the model in respect to reality.

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