Diarylethenes in Optically Switchable Organic Light‐Emitting Diodes: Direct Investigation of the Reversible Charge Carrier Trapping Process

Advanced Optical Materials, vol. 10

Abstract

Abstract The design, fabrication, and characterization of optically switchable organic light‐emitting diodes (OSOLEDs) based on the combination of the commercially available light‐emitting polymer poly(9,9′‐dioctylfluorene‐alt‐benzothiadiazole), F8BT, doped with a diarylethene derivative is reported. The photochromic activity of the dopant in the solid state has been investigated both via UV/vis absorption and photoluminescence spectroscopy, whereas the morphology of different blends is investigated via atomic force microscopy. OSOLEDs embedding dopant loadings of 1, 5, and 10 wt% exhibit optical responsivity with a maximum reversible optical threshold voltage shift of 4 V. The best performing devices containing 5 wt% dopant show a maximum current density and luminance ON/OFF ratio of ≈20 and ≈90, respectively. For the first time, the impact of the diarylethene isomerization on hole and electron transport has been decoupled and directly investigated, via the design, fabrication, and characterization of single‐carrier switchable devices based on the same blends. Not only do these results confirm the photo‐responsive trapping activity of the diarylethenes on both charge carriers, but they also demonstrate its asymmetry, with a predominant effect on electron transport that is over 3.4 times larger as compared to hole transport.

Authors 6

1. Giovanni Francesco Cotella

   London Centre for Nanotechnology · University College London

   Affiliation as printed

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology University College London London WC1E 6BT UK

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology, University College London, London, WC1E 6BT UK

2. Aurelio Bonasera corresponding

   Humboldt-Universität zu Berlin · National Interuniversity Consortium of Materials Science and Technology · University of Palermo

   Affiliation as printed

   Department of Chemistry & IRIS Adlershof Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany

   Department of Physics and Chemistry–Emilio Segrè University of Palermo, and INSTM–Palermo Research Unit viale delle Scienze, bdg. 17 Palermo 90128 Italy

3. Giuseppe Carnicella

   London Centre for Nanotechnology · University College London

   Affiliation as printed

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology University College London London WC1E 6BT UK

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology, University College London, London, WC1E 6BT UK

4. Alessandro Minotto

   London Centre for Nanotechnology · University College London

   Affiliation as printed

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology University College London London WC1E 6BT UK

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology, University College London, London, WC1E 6BT UK

5. Stefan Hecht corresponding Aachen Institute of Technical and Macromolecular Chemistry

   Humboldt-Universität zu Berlin · DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI–Leibniz Institute for Interactive Materials Forckenbeckstr. 50 52074 Aachen Germany

   Department of Chemistry & IRIS Adlershof Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany

   Institute of Technical and Macromolecular Chemistry RWTH Aachen University Worringer Weg 2 52074 Aachen Germany

   Department of Chemistry & IRIS Adlershof Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany

6. Franco Cacialli corresponding

   London Centre for Nanotechnology · University College London

   Affiliation as printed

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology University College London London WC1E 6BT UK

   Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology, University College London, London, WC1E 6BT UK