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Interaction of animal cells with organic semiconductors
Schildová, Veronika ; Thalerová, Sandra (referee) ; Víteček,, Jan (advisor)
This bachelor´s thesis was focused on study of biocompatibility of organic semiconductors. In introduction, organic semiconductors and their properties, benefits and features of selected representatives were described. In the following part biocompatibility definition and approaches for its assays including tests of cytotoxicity, material stability were presented. The last part was focused on overview of cell cultures, appropriate cultivation conditions and compounds of media for in vitro testing of biocompatibility. Experimental part showed the result of biocompatibility testing of materials. For this purpose murine 3T3 fibroblasts were used.
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Properties of solar cells based on polymer-silicon junction
Pavlovič, Dean ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Properties of solar cells based on polymer-silicon junction Author: Dean Pavlovič Department / Institute: Department of Macromolecular Physics Supervisor of the bachelor thesis: doc. RNDr. Jiří Toušek, CSc, Department of Macromolecular physics Abstract: The aim of this work is to study unconventional materials, namely conjugated polymers, as to be used for photovoltaic purposes. Among these polymers are polyaniline, derivative of polyphenylene vinylene and two derivatives of polythiophene. Four different methods are used to study some of the physical quantities of the samples, that should affect overall efficiency of solar power conversion. Firstly, I-V characteristics yields fill factor and indicates mechanism of charge transport. Method based on surface photovoltage (SPV) estimates diffusion length of the charge carriers - excitons. Impedance spectroscopy and particular method abbreviated CELIV both measure charge carrier mobility. Outcome of this work are the values of these quantities for some of the samples. Keywords: organic semiconductors, solar cells, mobility, diffusion length, current-voltage characteristic
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Low Voltage Converter for Organic Tranducers in Energy Harvesting
Znbill, Laila
The paper describes the possibilities of energy harvesting using organic semiconductors. It is shown that organic semiconductors enable a large variability and some of their properties may be better than by inorganic semiconductor materials. Simple and reliable JFET driven DC to DC converter was designed for low voltage applications as thermoelectric generators and single-cell solar panels. It is able to operate from the voltage of few tenths of Volt and the output voltage could be in the level of several Volts. The efficiency was found close to 50%. Material and production costs are significantly lower than in case of standard low power integrated circuits.
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Book of Abstracts and Programme. Polymers and Organic Materials for Electronics and Photonics: Science for Applications. Prague Meeting on Macromolecules /81./
Pfleger, Jiří ; Cimrová, Věra
The book of abstracts contains the summary of 8 plenary and 24 invited lectures, accompanied by 38 oral contributions and 88 posters presented at the conference. The main areas covered were the design, synthesis, processing and characterization of novel functional organic materials and polymers, electrical, photoelectrical, optical and nonlinear optical phenomena, organic and hybrid electronic and photonic devices, and advanced materials and composites for biosensors, bioelectronics, and biophotonics. Particular session was dedicated to applications in flexible and wearable organic electronics and smart packaging. Due to big expectations in the application field of large area printed electronics, wearable devices, printed RFIDs, displays, solar cells and sensors there is a growing demand to prepare polymers with better defined morphology and chemical and structural stability. Hence, improvement in the molecular design and new synthetic and processing routes is strongly required. A special emphasis was given to attract the scientists from the application field of printed electronics to provide a necessary feedback for further development of new materials with desired properties.
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Study of electric and photoelectric effects in organic semiconductors
Chomutová, Radka ; Toušek, Jiří (advisor) ; Pfleger, Jiří (referee)
This work studies various electrical properties of polymer layers of polyaniline, polythiophenes and poly(((benzothiadiazol)4,7-di(thien-2-yl)-5,6-difluoro-2,1,3-benzothiadiazol). Goal of this work is to determine electrical and photoelectrical properties as are electric conductivity, mobility of the free charge carriers, work function of the electrons and diffusion length of excitons. Conductivity was obtained through current and voltage contacts, mobility was measured by CELIV method (charge extraction by linearly increasing voltage). To determine work function a Kelvin probe was built and utilized. Diffusion length of excitons was determined from photovoltage spectrum formed by illuminating space charge region of the polymer.Space charge region on surface of the polymer can arise spontaneously or by laying suitable contact electrode. Powered by TCPDF (www.tcpdf.org)
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Some electrical and photoelectrical properties of organic semiconductors
Chomutová, Radka ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Some electrical and photoelectrical properties of organics semiconductors Author: Radka Chomutová Department: Department of Macromolecular Physics Supervisor: doc. RNDr. Jiří Toušek, CSc., Department of Macromolecular Physics Abstract: The object of this study is to determine some electrical and photoelectrical properties of polymer materials and their importance considering their usage as a solar cell. Especially, thin layers of polythiophene (PT1,PT2) and poly-3-hexylthiophene (P3HT) are measured and determined. Studied parameters are Fermi level by Kelvin method, the concentration of free charge carriers, conductivity, exciton diffusion length and thickness of the space charge region by surface photovoltage method (SPV). Obtained values were then added to older measurements with similar focus for polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV). Keywords: sollar cell, diffusion lenght, surface photovoltage method, Kelvin probe, organic layer
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Bio-inspired materials for aplications in organic electronics
Meindl, Jiří ; Pospíšilík, Karel (referee) ; Krajčovič, Jozef (advisor)
The bachelor ‘s thesis is a literary research, which summarise perspective bioinspired materials for organic electronic applications. Mainly focused are bioinspired and biocompatible materials in this thesis. The main area of interest is synthesis, characterization and application of these semiconducting materials. The first part of the thesis is focused on indigo, 6,6‘-dibromoindigo and thiophen derivatives of isoindigo copolymers. The second part of the thesis is all about biocompatible materials and applications of these materials in bio-protonic electronics. Malein-chitosan is described in this part as role model substance of bio-protonic electronics.
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Materials for organic electronics
Skrášek, Martin ; Zmeškal, Oldřich (referee) ; Vala, Martin (advisor)
The work contains literature search on organic electronics, especially organic solar cells. There is described in detail their principle of function and used materials. Also there are mentioned possibilities of synthesis of conjugated systems for this applications and methods of their structural, optical and electrical characterization. In experimental section and discussion is introduced synthesis of five new, various substituted derivates of benzylidenaniline and their characterisation together with another seven derivates, whose synthesis has been described in bachelor thesis. There is investigated influence of substituents to chemical shift of hydrogen on imine bridge and to position of absorption peaks in UV-Vis spectra. There also has been found method for fabrication of thin layers and solar cells with bulk heterojunction have been fabricated. Next, V-A characteristics and impedance spectra of the cells were recorded. According to obtained results, investigated systems act as photodiodes and in case of three derivates the photoinduced increase of electric current has been observed. But for application in solar cells it is necessary to shift the position of absorption spectra towards longer wavelengths.
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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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Organic semiconductors and their applications
Galbička, Tomáš ; Sedláček, Jiří (referee) ; Hubálek, Jaromír (advisor)
Bachelor’s thesis is deals with a problem of organic semiconductors, where are describe fundamental principles of charge transport and explanation of basic organic structures. There is described basic operation and layering of simple organic parts especially organic diode. There are practical tests of electrical properties of two different polymer diodes PLEDs. Where in this experimental part are present characteristics of these parts and them comparison at variant ilumination and mutually measuring.
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