Large‐Area Inkjet‐Printed OLEDs Patterns and Tiles Using Small Molecule Phosphorescent Dopant

Abstract

The main bottleneck in inkjet printing (IJP) is a stable and jettable ink formulation. This paper discusses the ink formulation for the small molecule phosphorescent dopant/host system. The study involves the estimation of Hansen solubility parameters (HSP) to formulate inkjet‐printed ink of an iridium complex‐based phosphorescent material, bis(4‐phenylthieno[3,2‐c]pyridinato‐N,C2') (acetylacetonate) iridium(III) (PO‐01) as dopant and 4, 40‐bis (carbazol‐9‐yl) biphenyl as the host of the emissive layer. Based on dopant and host HSP analyses, toluene and methyl benzoate are chosen as ink solvents. Our ink is stable for a month and can be replicated with great accuracy. The interaction of individual drops is examined in detail since resolution or film quality is highly influenced by the drop formation and spread on a substrate. Finally, an inkjet‐printed emissive layer is demonstrated on both glass and flexible substrates. The fabricated devices exhibit the maximum current efficiency and luminance of 6.4 cd A−1 and 5781 cd m−2. A technique is also shown to print large‐area organic light‐emitting diode (OLED) devices having different patterns without patterning or pixelization of the active area of the electrodes. Up to 80 × 80 mm2 large‐area OLED tiles are made using IJP of the emissive layer.

Single-Step Inkjet-Printed Dielectric Template for Large Area Flexible Signage and Low-Information Displays

“…Therefore, for inkjet printing, the modulation of SU-8 ink is desirable. Our previous work showed that a binary solvent system could solve the rapid evaporation of solvent at the nozzle air interface . Therefore, we tried to find the most suitable solvent that could be used with the base solvent in a binary solvent system.…”

“…Dielectric polymer ink drop generation is affected by several piezo-actuated printhead control parameters. , We go with the standard trapezoidal waveform reported in previous work for the formation of drops, consisting of three distinct phases (inset image Figure d) . The first phase is the rise time ( t r ), the amount of time it takes for the applied voltage to reach its peak, resulting in negative pressure inside the nozzle chamber, which starts drawing ink from the reservoir into the ink chamber.…”

“…34,35 We go with the standard trapezoidal waveform reported in previous work for the formation of drops, consisting of three distinct phases (inset image Figure 2d). 23 The first phase is the rise time (t r ), the amount of time it takes for the applied voltage to reach its peak, resulting in negative pressure inside the nozzle chamber, which starts drawing ink from the reservoir into the ink chamber. The second phase is the hold time (t h ), the amount of time the voltage across the membrane of a vibrating element remains at its peak.…”

Luminescent Au(III)–M(I) (M = Cu, Ag) Aggregates Based on Dicyclometalated Bis(alkynyl) Gold Anions

“…Phosphorescent organic light-emitting diodes (OLEDs) have been traditionally dominated by platinum­(II) − and iridium­(III) − complexes as photoemitters. However, in recent years, gold­(III) complexes, particularly those based on 2-arylpyridine (C ∧ N) and 2,6-biphenylpyridine (C ∧ N ∧ C) pincer ligands as chromophores, have emerged as excellent alternatives. − These ligands have been found to be effective platforms for stabilizing Au­(III) against reduction − and, at the same time, generate emissive compounds.…”

Self-cleaning and fully polymer-based super-moisture-resistant gas barrier coating films with 2D polymers for flexible electronic devices and packaging applications

“…Much research is underway to develop large-area FOEDs using R2R processing by employing inkjet printing, spray coating and slot die coating, but non-vacuum R2R processing of large-area thin films/GDBFs also requires more attention to obtain fully R2R FOEDs in future advanced processing. [28][29][30] Various solution-processed GDBFs have already been reported for packaging applications in food, pharmaceutical and flexible electronics industries. [31][32][33][34][35][36][37] Recently, various inorganic 2D materials, such as hexagonal boron nitride (hBN), reduced graphene oxide (rGO), and double layered hydroxide (LDH) clay with polyelectrolytes, have been explored for the fabrication of GDBFs using a layerby-layer (L-B-L) method.…”