Digitally Printed Molecularly Oriented Organic Semiconductors for Optoelectronic Devices
Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
Physical Chemistry of Solids and Surfaces, Material Characterisation
Final Report Abstract
The overall objective of the project was the control of the molecular orientation of solution processable organic semiconductors (OSCs), the characterization of the deposited films and the fabrication of optoelectronic devices. We investigated the self-organization of organic semiconductor thin films by using a crystallisable additive in the ink formulation that serves as a template during the drying process in an inkjet or coating process. We selected 1,3,5- trichlorobenzene (TCB) as the most suitable crystallisable additive which properties made it the most compatible with the utilized deposition processes. This selection was performed by studying reference insulating polymer systems with defined molecular structures. We analyzed the orientation degree as a function of inkjet printing parameters for the semi conductive polymers PIF-PTAA. Due to its complex molecular structure, PIF-PTAA usually forms amorphous films. The results showed that TCB induces organization in the backbone of polymer however, the directionality of the film heavily depended on processing conditions. Thus, the results suggested that the parameter space of inkjet printing (i.e. viscosity window, surface tension) plus the complexity of molecular structures of OSCs makes it very difficult to establish general rules for inkjet printing processing. Thus, we continued to investigate directional coating processes. We focused on polymer:polymer and polymer:small molecule blends which had compatible electronic properties to form a bulk-heterojunction. After optimization of the deposition, we demonstrated polarization sensitive organic photodetectors (pOPDs) where the polarization detection is dictated by the anisotropic absorption of the molecularly oriented films. We demonstrated pOPDs made of polymers such as P3HT and N2200 and small molecules such as IDTBR which are relevant to many optoelectronic applications. These devices were enabled by a novel gas-assisted coating process where the gas flow is used to improve molecular alignment by guiding the drying front. In summary, we demonstrated that both inkjet printing and gas-assisted drying are promising processes to control the molecular alignment of OSCs films. In summary, we achieved the main objective of the project by showing that the molecular alignment can be utilized to produced OPDs which would not need any additional filter to detect linearly polarized light, thus potentially simplifying the fabrication process of future optical systems.
Publications
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Materials Research Society Fall Meeting, (2020 Boston, USA), Oral Presentation Online, “Ink Engineering for Color–Selective Printed Organic Photodiodes and Filterless Multichannel Visible Light Communication”
Gerardo Hernandez-Sosa
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Anisotropic optical behavior of an amorphous organic polymer locally aligned by inkjet-printing. Progress in Organic Coatings, 154, 106184.
Lindberg, Frida W.; Synnatschke, Kevin; Rödlmeier, Tobias; Brenner, Philipp; Krings, Maximilian; Dietl, Martin C.; Lemmer, Uli; Backes, Claudia & Hernandez-Sosa, Gerardo
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“Uniaxially-ordered macromolecular systems for polarized photodetectors”, KIT-Fakultät für Elektrotechnik und Informationstechnik, Submitted (15.03.2021)
Hadhemi Mejri
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Gas-assisted blade-coating of organic semiconductors: molecular assembly, device fabrication and complex thin-film structuring. Nanoscale, 14(47), 17743-17753.
Mejri, Hadhemi; Haidisch, Anika; Krebsbach, Peter; Seiberlich, Mervin; Hernandez-Sosa, Gerardo & Perevedentsev, Aleksandr
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Materials Research Society Spring Meeting (2022 Hawaii, USA), Oral Presentation ”Polarized photodetectors based on oriented organic semiconductors: Fabrication, dark-current suppression and applications”
Online Aleksandr Perevedentsev
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Materials Research Society Spring Meeting (2022 Hawaii, USA), Poster Presentation ”Aerosol-Jet Printed Blocking Layers and Stretchable Platforms for Organic Photodiode Applications ”
Mervin Seiberlich
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Polarization‐Sensitive Photodetectors Based on Directionally Oriented Organic Bulk‐Heterojunctions. Advanced Optical Materials, 10(7).
Perevedentsev, Aleksandr; Mejri, Hadhemi; Ruiz‐Preciado, Luis A.; Marszalek, Tomasz; Lemmer, Uli; Blom, Paul W. M. & Hernandez‐Sosa, Gerardo
