Design and implementation of a light sensor array for imaging applications based on organic thin-film technology on foil

Abstract: Organic thin-film transistors (TFTs) were reported for the first time nearly thirty years ago. Since that time, TFTs attracted great interest in academia and industry to build large-area, mechanically-flexible and possibly disposable electronic systems on a variety of unconventional substrates, such as plastic, textile and paper. This thesis aims at the implementation of an imaging system composed of a photodetector array, that is based on a combination of conducting polymer and fullerene derivative, and the corresponding readout circuits, that are based on organic TFTs. For the design, simulation and optimization of the readout circuits, an analytical model that describes the static behavior of the TFT was derived. This model is based on a novel generic method for the extraction of the current-voltage characteristics of the organic TFTs that specifically accounts for the individual contributions of the source and drain contacts and their nonlinear behavior. Two different circuit-level topologies for the transimpedance readout circuit were considered, implemented, measured and analyzed. The first topology is a self-biased transimpedance amplifier based on a gain-boosted operational amplifier. The second topology is a low-power common-gate gain-boosted transimpedance amplifier. The common-gate transimpedance amplifier has shown its superiority in terms of process complexity, linearity, stability, response time and power consumption. The imaging system, that combines the photodetector array and the readout electronics, fabricated on separate plastic films, is thoroughly discussed highlighting the challenges and limitations posed by the organic thin-film technology. The output voltages of the light sensors were read and converted into a 20-pixel grayscale image displayed on a computer monitor to visualize the functionality of the system. Further, considering the advantages of digital signal processing (DSP) of being highly precise, accurate, robust and immune to noise, analog-to-digital (A/D) modulation of the photodetector current is also of interest in this work. The implementation of a first-order 1-bit continuous-time delta-sigma modulator is presented. The circuit-level design for each of the three building blocks of a delta-sigma modulator, the integrator, 1-bit quantizer and 1-bit digital-to-analog converter (DAC), is thoroughly discussed, highlighting the state-of-the-art for each block

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2020

Klassifikation und Themen

• Klassifikation: Elektrotechnik, Elektronik
• Schlagwort: Design ; Technology

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2020
• Urheber: Elsaegh, Samar
• Beteiligte Personen und Organisationen: Manoli, Yiannos ; Zappe, Hans P. ; Albert-Ludwigs-Universität Freiburg. Institut für Mikrosystemtechnik ; Albert-Ludwigs-Universität Freiburg. Fakultät für Angewandte Wissenschaften

Weitere Informationen

• DOI: 10.6094/UNIFR/174484
• URN: urn:nbn:de:bsz:25-freidok-1744841
• Rechteinformation: Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:48 MEZ