This bachelor thesis presents the fabrication and evaluation of large-scale full-solution roll-to-roll processed, ITO-free flexible organic solar cells in a modified inverted device geometry by gravure printing on a discrete laboratory-scale printing system.
The layer stack is based on flexible PET substrate whereupon the back silver cathode was printed on top. The electron transport layer of ZnO and a double light absorbing photoactive layer of P3HT:PCBM, the hole transport layer of PEDOT:PSS and front silver anode were printed consecutively. All layers were roll-to-roll gravure printed from solution under full ambient vacuum-free conditions at a web speed of 2 m min−1. The completed solar cells were characterized by J-V and comprising layers by light beam induced current measurements. For fast testing and reproducibility experiments the remaining layers of the stack after each gravure printed film were deposited by slot-die coating and flexographic printing on a single roll coating system. Unfortunately functional organic solar cells of a fully gravure printed layer stack could not be found. A power conversion efficiency of 0.15 % of partly roll-to-roll gravure printed and residuary roll-based slot-die coated and flexographic printed organic solar cells under AM1.5G illumination was obtained.
The thesis contains a brief introduction in the topic of renewable energies and organic photovoltaic followed by the state of art in two-dimensional gravure printing organic solar cells and the motivation to particularly foreground this fabrication method. In the fundamentals part the working principle, device geometries, affiliated by the concept of ITO-free organic solar cells and materials in an organic photovoltaic device including characterization methods are presented.
Afterwards large-scale manufacturing techniques of organic photovoltaic comprising coating and printing technologies are reviewed and the roll-to-roll manufacturing strategies are introduced. In the experimental part the design, machinery and equipment used and fabrication of gravure printed flexible organic solar cell are chronologically described in detail in connection with presenting and discussing the results after characterizing the completed solar cells. Challenges that were faced during the studies are described subsequently and solutions of appeared problems are presented. A conclusion and outlook finalizes the thesis.
Inhaltsverzeichnis (Table of Contents)
- Introduction
- The need for solar energy
- Generations of solar cell technology
- Research fields of organic solar cells
- State of art and motivation
- Fundamentals
- Working principle of OPV device
- Device geometries of OPV device
- ITO-free OPV device
- Materials in OPV device
- Characterization of OPV device
- J-V curve
- LBIC
- Large-scale manufacturing methods for OPV
- Coating technologies
- Slot-die coating
- Blade coating
- Spray coating
- Printing technologies
- Screen printing
- Gravure printing
- Flexographic printing
- Inkjet printing
- Summary of coating and printing techniques
- R2R concept and manufacturing strategies
- Coating technologies
- Experimental
- Gravure printing of silver back cathode
- Gravure printing of ZnO
- Gravure printing of active layer
- Gravure printing of PEDOT:PSS
- Gravure printing of silver front anode
- Deposition of remaining layers
- Characterization
- Results and discussion
- Gravure printed silver back cathode
- Gravure printed ZnO
- Gravure printed active layer
- Gravure printed PEDOT:PSS
- Gravure printed silver front anode
- Summary of results
- Challenges
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This bachelor thesis explores the fabrication and evaluation of large-scale, flexible organic solar cells. It focuses on the use of gravure printing in a modified inverted device geometry, aiming to achieve roll-to-roll processed, ITO-free solar cells on a flexible PET substrate. The main goal is to demonstrate the feasibility and performance of this manufacturing approach.- Large-scale, roll-to-roll processing of organic solar cells
- Gravure printing as a fabrication method for ITO-free devices
- Device performance and efficiency of gravure-printed organic solar cells
- Challenges and solutions associated with gravure printing in organic solar cell fabrication
- Comparison of gravure printing with other coating and printing techniques
Zusammenfassung der Kapitel (Chapter Summaries)
This thesis begins with an introduction to renewable energies and organic photovoltaic, followed by a review of the state-of-the-art in gravure printing of organic solar cells. The fundamentals of organic photovoltaic, including device working principle, geometries, materials, and characterization methods, are discussed in detail. The thesis then focuses on large-scale manufacturing methods for organic solar cells, with an emphasis on roll-to-roll processing. The experimental section describes the design, machinery, and fabrication processes used to create the gravure-printed flexible organic solar cells. The results and discussion sections present the characterization data of the fabricated solar cells, including challenges encountered during the study and solutions developed.Schlüsselwörter (Keywords)
This thesis centers on the research and development of large-scale, flexible organic solar cells fabricated using gravure printing. Key focus areas include roll-to-roll processing, ITO-free devices, device efficiency, and challenges encountered in the fabrication process. The work also examines other coating and printing techniques for organic solar cell production, such as slot-die coating and flexographic printing.Frequently Asked Questions
What is the focus of this bachelor thesis?
The thesis focuses on the fabrication and evaluation of large-scale, ITO-free flexible organic solar cells using gravure printing in a roll-to-roll process.
What does "ITO-free" mean in the context of solar cells?
It means the device does not use Indium Tin Oxide (ITO) as a transparent electrode, seeking alternatives to reduce costs and improve flexibility on PET substrates.
Which printing technique was primarily used?
Gravure printing was the primary method used for depositing the silver cathode, ZnO layer, active layer (P3HT:PCBM), and other components of the solar cell stack.
What efficiency was achieved in the study?
A power conversion efficiency (PCE) of 0.15% was obtained for solar cells that were partially gravure printed and combined with slot-die coating and flexographic printing.
What are the main challenges in gravure printing solar cells?
The thesis describes challenges in achieving functional fully gravure-printed stacks, including issues with layer thickness, ink compatibility, and maintaining vacuum-free ambient conditions.
How are the solar cells characterized in this work?
The cells were characterized using J-V (current-voltage) curve measurements and Light Beam Induced Current (LBIC) measurements to evaluate performance and uniformity.
- Arbeit zitieren
- Johannes Michael Küffner (Autor:in), 2014, Large-scale full-solution, vacuum-free gravure printed ITO-free flexible organic solar cells, München, GRIN Verlag, https://www.grin.com/document/287304
