Charge transport in 2,6-bis(5′-hexyl-2,2′-bithiophene-5-yl)naphthalene-based organic devices

• We synthesized oligothiophenes suitable for OFETs and OLEDs.
• We reconstructed the energy band diagram of new oligothiophene.
• Exciton complex formation at organic/organic interface in OLED was observed.

Organic semiconductor 2,6-bis(5′-hexyl-2,2′-bithiophene-5-yl)naphthalene (H2T26N) is employed as an active layer in organic field-effect transistors (OFETs) or as a hole-transport layer in organic light-emitting diodes (OLEDs). In OFET device the p-type conductivity is confirmed and the hole mobility as high as 0.34 cm2/V s is achieved. The emission spectrum of ITO/H2T26N/tris(8-quinolinolato) aluminum (Alq3)/Ca OLED shows emission peaks which cannot be ascribed to either the H2T26N or Alq3 layer. Through studies of photoluminescence spectra and electrochemical properties we demonstrate that the additional feature results from an exciplex at the H2T26N/Alq3 bilayer interface.

Figure optionsDownload as PowerPoint slide