Acid dyeing for green solvent processing of solvent resistant semiconducting organic thin films

Cayley R. Harding, Jonathan Cann, Audrey Laventure, Mozhgan Sadeghianlemraski, Marwa Abd-Ellah, Keerthan R. Rao, Benjamin Sidney Gelfand, Hany Aziz, Loren Kaake, Chad Risko, Gregory C. Welch

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The alcohol and water-based processing of a perylene diimide (PDI) organic semiconductor into large area and solvent resistant films is reported. The compound, PDIN-H, is an N-annulated PDI dye with a pyrrolic NH functional group that can be deprotonated to render the material soluble in polar solvents. Addition of NaOH to mixtures of PDIN-H in 1-propanol results in a progressive color change from orange/red to purple with increasing equivalents of base. Use of 1 molar equivalent of NaOH was found to fully dissolve the PDIN-H in alcohol solvents up to a concentration of 10 mg mL-1. Primary alcohols 1-propanol to 1-hexanol as well as 2-propanol were used. All solutions were readily spin-coated or slot-die coated into uniform thin films. Solutions in 1-propanol could be coated with concentrations up to 50 mg mL-1. All films were red in color and characterized by optical absorption spectroscopy confirming the existence of the parent PDIN-H species in the film. Single crystal X-ray diffraction was used to determine the molecular packing of PDIN-H. Films showed no signs of dewetting, swelling, or dissolution upon exposure to 2-propanol, water, or o-xylene via coating or dipping indicating they were solvent resistant. To exploit the semiconducting properties of these PDIN-H films, organic photovoltaic devices were fabricated using the films as electron transport layers in inverted type P3HT:PC61BM bulk heterojunction devices. Moreover, the PDIN-H films changed from red to purple upon exposure to butylamine vapors which prompted the investigation of hydroxide free processing. Indeed, films of PDIN-H were easily formed by processing with 1-propanol/butylamine or water/butylamine solutions. This journal is

Original languageEnglish
Pages (from-to)2959-2969
Number of pages11
JournalMaterials Horizons
Issue number11
StatePublished - Nov 2020

Bibliographical note

Funding Information:
GCW acknowledges CFI JELF (34102), CRC, WED, and the University of Calgary. This work was supported by the NSERC Green Electronics Network (GreEN) (NETGP 508526-17), the NSERC Discovery grants program (RGPIN 2019-04392 and 2014-04940), and the NSERC Strategic grants program (STPGP-521458-2018). AL and MAE acknowledge NSERC for postdoctoral fellowships. JC acknowledges NSERC for a graduate scholarship. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund (CFREF). KRR and CR acknowledge the National Science Foundation (Cooperative Agreement 1849213) and the Office of Naval Research Young Investigator Program (N00014-18-1-2448) for their support of this project at the University of Kentucky. Supercomputing resources on the Lipscomb High Performance Computing Cluster were provided by the University of Kentucky Information Technology Department and the Center for Computational Sciences (CCS). Martin Kiener (FOR Technologies) is thanked for help and support with the slot-die coating equipment and experiments.

Publisher Copyright:
© The Royal Society of Chemistry.

ASJC Scopus subject areas

  • Materials Science (all)
  • Mechanics of Materials
  • Process Chemistry and Technology
  • Electrical and Electronic Engineering


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