Upscaling Organic Electronic Devices

Conventional electronics based on silicon, germanium, or compounds of gallium require prohibitively expensive investments. A state-of-the-art microprocessor fabrication facility can cost up to $15 billion while using environmentally hazardous processes. In that context, the discovery of solution-processable conducting (and semiconducting) polymers stirred up expectations of ubiquitous electronics because it enables the mass-production of devices using well established high-volume printing techniques. In essence, this thesis attempts to study the characteristics and applications of thin conducting polymer films (<200 nm), and scale them up to thick-films (>100 μm). First, thin-films of organic materials were combined with an electric double layer capacitor to decrease the operating voltage of organic field effect transistors. In addition, ionic current-rectifying diodes membranes were integrated inside electrochromic displays to increase the device’s bistability and obviate the need for an expensive addressing backplane. This work also shows that it is possible to forgo the substrate and produce a self-standing electrochromic device by compositing the same water-processable material with nanofibrillated cellulose (plus a whitening pigment and high-boiling point solvents). In addition, we investigated the viability of these (semi)conducting polymer nanopaper composites in a variety of applications. This material exhibited an excellent combined electronic-ionic conductivity. Moreover, the conductivities in this easy-to-process composite remained constant within a wide range of thicknesses. Initially, this (semi)conducting nanopaper composite was used to produce electrochemical transistors with a giant transconductance (>1 S). Subsequently, it was used as electrodes to construct a supercapacitor whose capacitance exceeds 1 F. Contribution to scholarly articles • Ultra-low voltage air-stable polyelectrolyte gated ntype organic thin film transistors A. Malti, E. O. Gabrielsson, M. Berggren, X. Crispin Appl. Phys. Lett. 99, 063305 (2011) Contribution: Most of the experimental work and most of the writing/editing of the manuscript. • Low-voltage ambipolar polyelectrolyte-gated organic thin film transistors A. Malti, M. Berggren and X. Crispin Appl. Phys. Lett. 100, 183302 (2012) Contribution: All experimental work and most of the writing/editing of the manuscript. • An Electrochromic Bipolar Membrane Diode A. Malti, E. O. Gabrielsson, X. Crispin, M. Berggren Adv. Mater. 27, 3909–3914 (2015) Contribution: Most of the experimental work and most of the writing/editing of the manuscript. • A substrate-free electrochromic device A. Malti, R. Brooke, X. Liu, D. Zhao, P. Andersson Ersman, M. Fahlman, M. Berggren, X. Crispin Submitted (Aug. 2015) Contribution: Most of the experimental work and most of the writing/editing of the manuscript. • Enabling organic power electronics with a cellulose nano-scaffold A. Malti, J. Edberg, H. Granberg, Z. Khan, J. Andreasen, X. Liu, D. Zhao, H. Zhang, Y. Yao, J. Brill, I. Engquist, M. Fahlman, L. Wåberg, X. Crispin, M. Berggren Submitted (Sep. 2015) Contribution: Some of the experimental work and some of the writing/editing of the manuscript. Scholarly articles beyond the scope of this thesis • Optimization of the thermoelectric figure of merit in the conducting polymer poly(3,4-ethylenedioxythiophene) O. Bubnova, Z. Khan, A. Malti, S. Braun, M. Fahlman, M. Berggren, X. Crispin Nature Mater. 10, 429–433 (2011) Contribution: Preliminary experimental work and minor involvement in the writing/editing of the manuscript.