Identification of both bipolaron and electron-hole pair contributions to organic magnetoresistance in a regioregular polythiophene device

Sahin-Tiras K., Riedl A. D., Wohlgenannt M., Rybicki J.

ORGANIC ELECTRONICS, vol.48, pp.198-203, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 48
  • Publication Date: 2017
  • Doi Number: 10.1016/j.orgel.2017.05.051
  • Journal Name: ORGANIC ELECTRONICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.198-203
  • Keywords: Organic light emitting diode, Regioregular polythiophene, Organic magnetoresistance, Bipolaron model, Electron-hole pair model
  • Erciyes University Affiliated: No

Abstract

We study organic diodes of regioregular polythiophene (RR-P3HT) fabricated with various anode and cathode materials to determine the importance of bipolarons and electron-hole pairs for magnetoconductance (MC). RR-P3HT is selected because it can display both negative or positive MC depending on the electrodes used to fabricate the devices. Near-unipolar, electron-only, devices show negative MC at all voltages. We attribute this to the bipolaron mechanism. Both a negative (low voltage) and positive (high voltage) MC are measured in bipolar devices. The positive and negative MC are attributed to the electron-hole pair mechanism and the bipolaron mechanism, respectively. This conclusion is supported by an analysis of the electroluminescence efficiency versus voltage and the magnetic field effect on the electroluminescence quantum efficiency. (C) 2017 Published by Elsevier B.V.