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Optimization of organic solar cells
Kratochvíl, Matouš ; Novák, Vítězslav (referee) ; Weiter, Martin (advisor)
This diploma thesis focuses on the preparation of large-scale organic solar cells using techniques compatible with large volume production. The theoretical part consists of research summarizing the basic theoretical background of the function of organic solar cells and the current state of investigation of the shift from laboratory to large-scale production. The experimental part deals with the optimization of methods of preparation of layers of structure of solar cells, which can be converted into industrial scale.
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Energetic interactions between electon-donors and acceptors for photovoltaic solar cells
Hrabal, Michal ; Heinrichová, Patricie (referee) ; Vala, Martin (advisor)
The aim of this bachelor thesis is to study a charge transfer between materials that could be used for development of new organic solar cells. The charge transfer is studied by a quenching of fluorescence. The thesis is divided into theoretical and experimental part. The basic knowledge needed for correct interpretation of measured data is summarized in the first part. Special attention is paid to the photoinduced electron transfer. Then, the processes of conversion of solar energy into electric energy and properties of potential materials are also discussed. Architecture of organic solar cells is mentioned in the end of the work. The practical part contains the study of quenching of fluorescence by fullerene derivatives and compares the efficiency of quenching to standard materials.
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Organic materials for photonic applications
Kubíček, Václav ; Heinrichová, Patricie (referee) ; Weiter, Martin (advisor)
The bachelor's thesis focuses on characterisation of optical properties of substituated diphenyl-distyrylbenzenes for their potancial aplication in organic photonics. Dependance of molecular structure, used solvent and form on optical properties was studied. The theoretical part consists of research about current situation in organic photonics, it focuses mainly on organic photovoltaics. Results show that optical properties fundamentally depend on electronacceptor power of substituated group. Optical properties are also influenced by used solvent.
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Deposition and study of optoelectronic properties of thin films for organic photonics
Nagyová, Veronika ; Hubálek, Jaromír (referee) ; Weiter, Martin (advisor)
This diploma thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy, factors influencing photovoltaic conversion efficiency and materials using for preparation of organic solar cells. The practical part includes the preparation of solar cells and characterization of optical and electrical properties of the studied materials in thin layers and solutions. Used materials were conjugated polymers and derivatives of fullerenes.
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Organic solar cells based on lowmolecular materials
Omasta, Lukáš ; David, Jan (referee) ; Weiter, Martin (advisor)
This bachelor thesis is focused on characterization of new organic materials suitable for use in solar cells. In the theoretical part, there is research on organic solar cells together with description of the photovoltaic energy conversion. In this part, description of the structure and general properties of materials used to produce solar cells is given. The individual characterization methods are also described. The practical part includes the preparation of thin layers of organic materials and their optical characterization. Preparation of solar cells with classic structure is also included together with evaluation and comparison of their photoconductivity and efficiency.
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Application of plasmonics in organic photovoltaics
Láska, Martin ; Fejfar, Antonín (referee) ; Šikola, Tomáš (advisor)
Tato diplomová práce se zabývá studiem plasmonicky navýšené absorpce vedoucí ke zlepšení účinnosti organických solárních článků. K navýšení absorpce světla ve fotoaktivní vrstvě jsou použity koloidní nanočástice stříbra. Rozptyl světla z nanočástic střibra do fotoaktivní vrstvy představuje jedno z možných řešení, jak navýšit celkovou účinnost fotovoltaických zařízení. Simulace elektromagnetických jevů jsou pro statické podmínky prováděny v softwaru Lumerical (Lumerical Solutions, Inc.). Je zkoumána absorpce ve fotoaktivní vrstvě v závislosti na konfiguraci stříbrných nanočástic. Simulace potvrzují, že ve fotoaktivní vrstvě, která je modifikovaná nanočásticemi stříbra, dochází k navýšení absorpce. Abychom potvrdili výsledky simulací, bylo vyrobeno několik stříbrem modifikovaných vzorků. Vzorky byly pro tento druh experimentu připravené z poly(3-hexyltiofenu):[6,6]-fenyl-C61-butyric-acid-metyl esteru. U některých, nanočásticemi stříbra modifikovaných, vzorků dochází k navýšení tvorby excitonů, v důsledku čehož je pozorován nárůst fotoproudu. V této práci je zahrnut teoretický i experimentální přístup k dané problematice.
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Preparation and characterization of thin organic photovoltaic layers
Kratochvíl, Matouš ; Zmeškal, Oldřich (referee) ; Weiter, Martin (advisor)
This bachelor thesis focuses on preparation of organic solar cells and characterization of their properties. The theoretical part consists of literature search focused on current findings in this area and basic theoretical knowledge of the mechanisms of solar cells functioning. The experimental part of the thesis deals with the preparation of solar cells, targeting large cells, and characterization of basic electrical and optical properties of these cells.
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Organic solar cells based on polymers
Nagyová, Veronika ; David, Jan (referee) ; Weiter, Martin (advisor)
This bachelor thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy and the structure of organic solar cells. The practical part includes the preparation of solar cells and characterization of basic optical and electrical properties of the studied materials.
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Advanced materials for organic photonics
Zvěřina, Libor ; Salyk, Ota (referee) ; Weiter, Martin (advisor)
The theoretical part of this bachelor’s thesis deals with principles, structure and optimization of organic solar cells and properties of low-molecular advanced materials – diketopyrrolopyrroles, which are used in photovoltaics. In the experimental part six derivatives of diketopyrrolopyrrole were analysed by optical characterisation. It was found that N-substitution does not influence optical properties. Length of conjugated system showed to be the key parameter. The longer conjugation is, the smaller band gap and the greater absorption intensity are obtained. Based on the previous study, four materials were chosen to prepare solar cells. Influence of thermal annealing and gradual-annealing was studied. Current density, fill factor and photovoltaic conversion efficiency were increased by annealing. Gradual-annealing have not lead to further improvement. Finally, solar cells were optimized by 1,8-diiodooctane as an additive. It was found that effect of thermal annealing can be replaced with the additive. The best photovoltaic conversion efficiency was measured on the cell with 0,2 vol. % of additive in active bulk heterojunction.
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