有機平板波導元件電激發光特性之研究

Study of Electroluminescent Property of Organic Slab Waveguide Device

黃裕軒(Yu-syuan Huang)

指導教授 ： 張瑞芬

國立中央大學/理學院/照明與顯示科技研究所/碩士(2014年)

摘要

本論文利用有機高分子材料 PVK (Poly(9-vinylcarbazole)) 為空間層、有機小分子螢光材料BSB-Cz (4,4’-bis[(N-carbazole) styryl] biphenyl) 為發光層製作有機平板波導元件，並探究此板波導元件在高電流密度驅動之下電激發光特性。我們先從電性上的考量優化 PVK 之厚度，得到在 100 nm 的 PVK 有較佳的光電特性表現；其後固定 PVK 厚度為 100 nm，改變發光層 BSB-Cz 之厚度，發現在 BSB-Cz 厚度為 250 - 260 nm 時，會使元件側向量測到的截止波長落在 BSB-Cz 之 0-1振動放射峰，此為光增益係數最高之波段。最後我們固定 PVK 為 100 nm、BSB-Cz 為 250 或 260 nm，利用脈衝電壓給予高能量的注入，觀察側向發光強度與激發能量之變化。我們發現此有機波導元件在高電流密度驅動下仍具備相當穩定的電激發光效率。一般元件在電流密度超過 1 A/cm2 時，其側向發光強度與激發能量呈線性成長，沒有明顯發光衰減之情形。而有趣的是，在少數發光特別優異的元件中，有觀察到類似光放大的現象。相信在更進一步的優化電性與量測條件之下，能證實電激發自發輻射放大之現象。

關鍵字

有機 ； 平板波導元件 ； 電激發光

並列摘要

In this thesis, we used a polymer material, PVK (Poly(9-vinylcarbazole)), as the spacer and a fluorescent small molecule, BSB-Cz (4,4’-bis[(N-carbazole) styryl] biphenyl), as the emission layer to fabricate the organic multilayer slab waveguide device, and investigated the electroluminescent properties of the device driven with high current density. First, we optimized the electrically property of devices by varying the thickness of PVK. The best performance was obtained with 100 nm thick PVK. After then, we fixed the PVK thickness at 100 nm and changed the thickness of emission layer (BSB-Cz). For 250-260 nm thick BSB-Cz the cutoff wavelength measured from the side emission spectrum was found to coincide with the 0-1 vibronic peak of BSB-Cz, which corresponds to the regime of the highest gain coefficient. Finally, we fixed the thickness of 100 nm for PVK and 250 nm or 260 nm for BSB-Cz and used pulse bias to drive the device with high energy. The variation of side emission intensity against pump energy was investigated. We observed that such a slab waveguide device could exhibit stable emission efficiency when driving with high current density. In general, the devices show a linear growth of the side emission versus pump energy without apparent emission roll-off phenomenon as the current density exceeds 1 A/cm2. Intriguingly, in some exceptional devices with superior emission property, we observed light amplification-like phenomena. We believe that with further optimization of the electrical properties and measurement conditions, the electrically pumped ASE phenomenon can be demonstrated.

並列關鍵字

Organic ； Slab Waveguide Device ； Electroluminescent

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