| Summary: | 博士 === 國立臺灣大學 === 光電工程學研究所 === 106 === This dissertation is to investigate the carrier injection and transport mechanisms in organic light-emitting diodes, mainly associating with the hole injection layer and electron transport layer. There are four sections in this dissertation. First, we demonstrate the use of self-assembly to fabricate solution-processed molybdenum oxide films by simply casting a metal oxide solution onto an indium tin oxide substrate. The devices with self-assembled hole injection layers exhibited nearly double the efficiency of one made with commonly used evaporated molybdenum oxide hole injection layers. Second, we demonstrate the use of solution-processed molybdenum trioxide nanoparticle-decorated molybdenum disulfide (MoS2) nanosheets (MoS2/MoO3) as hole injection layer in organic lighting diodes. The device performance is shown to be significantly improved by the introduction of such MoS2/MoO3 hole injection layer without any post-ultraviolet-ozone treatment, and is shown to better the performance of devices fabricated using conventional. Third, The influence of the electron-transport layer on an Ir(ppy)3-based phosphorescent light-emitting diode was investigated. We found that although devices with pyridine-containing ETLs, bis-1,2-(3,5-di-3-pyridyl-phenyl)benzene (B3PyPb) and 1,3,5-tri(m-pyrid-3-ylphenyl)benzene (TmPyPb), achieved very high efficiencies, their lifetimes were worse than other commonly used ETLs. However, the device lifetime can be increased by utilizing a high-stability electron-blocking layer to avoid triplet-polaron annihilation by separating the excitons in the emitting layer and the polarons in the electron transport layer. Fourth, we will discuss a series of standard organic light-emitting diode with various hole-injection layers in order to identify the origin of luminance degradation and the role played by hole injection layers in device lifetime. Band alignment results in the formation of a well-formed charge transfer interface capable of preventing the accumulation of charge at the indium tin oxide/hole transport layer interface. Keywords: Light-emitting diodes, MoO3, MoS2, Hole injection layer, Electron transport layer, Device lifetime.
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