The improved performance in inverted organic light-emitting diodes using the hybrid- p-doped hole transport layer
Abstract
The inverted organic light-emitting diodes (IOLEDs) have been fabricated using the hybrid-p-doped hole transport layer consisting of MoO3-doped N,N'-bis-(1-naphthl)-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB:MoO3) and 2,3,5,6-Tetrafluoro-7,7,8,8,-tetracyano-quinodimethane-doped NPB (NPB:F4-TCNQ). Compared with the IOLED using the 20 nm NPB:MoO3/Al, the one using the 10 nm NPB:F4-TCNQ/10 nm NPB:MoO3/Al showed increased performance, attributed to the higher conductivity of NPB:F4-TCNQ than NPB:MoO3, reducing the ohmic loss in hole conduction through the combined 10 nm NPB:F4-TCNQ and 10 nm NPB:MoO3 than through the 20 nm NPB:MoO3; it also presented improved performance than the IOLED using the 20 nm NPB:F4-TCNQ/Al, ascribed to the non-ohmic contact formation between NPB:F4-TCNQ and Al, resulting from that the p-doping effect of F4-TCNQ in NPB was significantly suppressed by the Al deposition in the interfacial zone. The hybrid p-doping of hole transport layer can offer a large space to promote the performance of IOLEDs.
- Publication:
-
Applied Physics A: Materials Science & Processing
- Pub Date:
- August 2015
- DOI:
- 10.1007/s00339-015-9233-x
- Bibcode:
- 2015ApPhA.120..651Q
- Keywords:
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- MoO3;
- High Occupied Molecular Orbital;
- Driving Voltage;
- Hole Conduction;
- Hole Transport Layer