Pressure-assisted fabrication of organic light emitting diodes with MoO{sub 3} hole-injection layer materials

Journal Article · Sat Jun 21 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4881780· OSTI ID:22303998

Du, J. ^[1]; Anye, V. C.; Vodah, E. O. ^[2]; Tong, T. ^[1]; Zebaze Kana, M. G. ^[3]; Soboyejo, W. O. ^[1]

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1. The Princeton Institute for the Science and Technology of Materials (PRISM), Princeton, New Jersey 08544 (United States)
2. Department of Materials Science and Engineering, African University of Science and Technology, Abuja, Federal Capital Territory (Nigeria)
3. Physics Advanced Laboratory, Sheda Science and Technology Complex, Abuja, Federal Capital Territory (Nigeria)

In this study, pressures of ∼5 to ∼8 MPa were applied to organic light emitting diodes containing either evaporated molybdenum trioxide (MoO{sub 3}) or spin-coated poly(3,4-ethylene dioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) hole-injection layers (HILs). The threshold voltages for both devices were reduced by about half, after the application of pressure. Furthermore, in an effort to understand the effects of pressure treatment, finite element simulations were used to study the evolution of surface contact between the HIL and emissive layer (EML) under pressure. The blister area due to interfacial impurities was also calculated. This was shown to reduce by about half, when the applied pressures were between ∼5 and 8 MPa. The finite element simulations used Young's modulus measurements of MoO{sub 3} that were measured using the nanoindentation technique. They also incorporated measurements of the adhesion energy between the HIL and EML (measured by force microscopy during atomic force microscopy). Within a fracture mechanics framework, the implications of the results are then discussed for the pressure-assisted fabrication of robust organic electronic devices.

• OSTI ID: 22303998
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADHESION
ATOMIC FORCE MICROSCOPY
DOPED MATERIALS
ELECTRIC POTENTIAL
ELECTRONIC EQUIPMENT
ETHYLENE
FINITE ELEMENT METHOD
HOLES
IMPURITIES
INJECTION
LAYERS
LIGHT EMITTING DIODES
MOLYBDENUM OXIDES
ORGANIC SEMICONDUCTORS
PRESSURE RANGE MEGA PA
SIMULATION
SPIN
SULFONATES
SURFACES
YOUNG MODULUS