The authors studied the effect of thermal and electrical annealing on light emission of fluorescent one-layered organic light-emitting devices (OLEDs) doped with organic salts. From the annealed OLEDs, we clearly observed homogeneous and enhanced electroluminescent (EL) emission over the whole active area with fast responses. Moreover, improved efficiency was also observed from annealed phosphorescent OLEDs. These improved EL characteristics indicate that simultaneous annealing can induce proper adsorption of charged salt ions at the electrode surfaces, leading to enhanced electroluminescence of one-layered OLEDs due to increased and balanced injection of carriers.

We investigated an improved method for enhancing light emission in single-layer organic light-emitting devices (OLEDs) stimulated by thermal and electrical annealing. In this study, we introduced fluorescent single-layer OLEDs doped with organic salt, tetrabutylammonium tetrafluoroborate (Bu 4 NBF 4 ). The annealing process consisted of simultaneously treated by thermal and electrical annealing in a noble gas environment filled with argon gas. Comparing with nonannealed OLEDs, we clearly observed homogeneous and ehanced electroluminescent (EL) emission over the entire active area with fast response and improved efficiency from annealed OLEDs. According to these improved EL characteristics, we considerably assumed that these phenomenons leading to the enhanced EL of single-layer OLEDs due to increased and balanced injection of carriers are due to simultaneous annealing, which induces proper adsorption of charged salt ions on the electrode surface.

Previous studies on liquid gallium ion sources used an electrochemically etched tungsten wire with a coil-type heater. Such a structure requires excessive power consumption in the course of heating the liquid metal. In this study, a new structure is proposed that replaces the coil-type heater. It uses a gallium reservoir made of six pre-etched 250 µm tungsten wires that surround the needle electrode. Gallium loading at the reservoir is observed to be much more stable, resulting in an improved beam stability.

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