Organic light emitting diodes (OLEDs) have received wide attention and progress in impacting the electronics market. The progress of OLEDs in the market over their inorganic counterpart is principally due to their cost savings, flexibility, and excellent performance. As a result of the rising demands for next‐generation electronic devices with increased efficiency, high flexibility, reduced cost, and stretchability, there is a need for improvements of OLEDs. In order to fulfill these requirements, it is necessity to replace the transparent conductive electrode (TCE) with a better alternative. The conventionally used TCE, indium tin oxide (ITO), suffers from the scarcity of indium, increased cost, instability, and brittleness. Graphene is recognized as a suitable alternative to ITO because of its excellent properties including high optical transmittance, outstanding electrical conductivity, stability, and great mechanical flexibility. However, the performance of graphene as the TCE material in OLEDs is limited. Several efforts have been made to improve graphene's performance through electrode modifications. This review covers a summary of fabrication techniques for graphene‐based TCEs and their improvements. Finally, the application and performance of graphene‐based TCEs in OLED devices and the performance of such OLEDs are discussed.

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The magnetic hysteresis and viscosity of SrO(Fe2O3)6/PA-12 filaments with 5wt% and 26wt% was determined with a biaxial VSM. The hysteresis curves indicate that manufactured samples have a flow induced anisotropy with an easy plane perpendicular to the filament’s cylindrical axis. The Mx and My magnetic viscosity signals vary with field and field angle. The Mx magnetic viscosity is maximum in the easy plane and decreases to a factor of two along the macroscopic hard axis of the filament. The My magnetic viscosity is nearly zero along the hard axis and in the easy plane and is maximum for intermediate field angles.

Hard-magnetic 3D-printer filaments made of 40 wt. % SrO(Fe2O3)6/PA12 composites made using a twin-screw extruder are being studied to be used for Magnetic Field Assisted Additive Manufacturing (MFAAM). The time dependence of the magnetic properties above the softening temperature of the PA12 matrix but below the melting point was studied using a biaxial Vibrating Sample Magnetometer (VSM). Specifically, the rotation of the magnetic particles in the softened polymer matrix after the application of a rotation field was extracted from the time dependent biaxial VSM signals. Above 132 °C, the strontium ferrite particles can rotate in the nylon matrix. The measured time constant decreases with temperature and magnitude of the rotation field. Model calculations indicate that, for 40 wt. % SrO(Fe2O3)6/PA12 at rotation fields of 500 Oe, the effect of the demagnetizing field on the angle between the magnetic moment and the particle’s easy axis is negligible, allowing one to determine the dynamic “melt” viscosity from the measured transients. The dynamic viscosity decreases from 2 × 105 Pa s at 132 °C to 3.1 × 104 Pa s at 175 °C with a sharp kink observed near 140 °C that correlates with a relaxation from the α′c phase for PA12 observed by others. A yield shear stress was observed for small rotation fields at low temperatures resulting in non-perfect alignment of the magnetic particles. The implications of the measurement results for MFAAM are discussed.

To better understand Magnetic Field Assisted Additive Manufacturing (MFAAM) the effect of a magnetic field on the orientation and distribution of magnetic particles in a molten magnetic composite was studied. Vibrating Sample Magnetometer (VSM) measurements were made on Sr-ferrite/PA12 fused deposition modeling filaments of different packing fraction (5 and 40 wt. %). The rotation of the sample’s magnetic moment upon application of a field perpendicular to the easy axis was monitored with a biaxial VSM above the PA12’s softening temperature. The observed magnetic moment transients depend on the temperature, the applied alignment field, the packing fraction, and the initial field-anneal procedure. Longer field-anneals result in larger time constants and seem to induce a hurdle that prevents complete alignment at low temperatures and/or for small fields. Results indicate the molten composite is a non-Newtonian fluid that can support a yielding stress. Scanning Electron microscopy (SEM) images taken on field-annealed samples at 230 °C show strong chaining with little PA-12 left between individual Sr-ferrite particles suggesting that direct particle to particle interaction is the reason for the observed non-zero yielding stress. The melt viscosity of the composite increases with the number of thermal cycles above the melting temperature (Tm). Room temperature (RT) torque magnetometry measurements show that magnetic anisotropy depends on the field annealing process through induced shape anisotropy contributions originating from magnetic particle agglomerates.