研究生: |
李佳安 Lee, Chia An |
---|---|
論文名稱: |
具有奈米粒子之發光元件的製程與特性研究 Fabrication and Characteristics of Light Emission Devices with Nano-Particles |
指導教授: |
林皓武
Lin, Hao Wu |
口試委員: |
朱治偉
Chu, Chih Wei 段興宇 Tuan, Hsing Yu 陳學仕 Chen, Hsueh Shih |
學位類別: |
碩士 Master |
系所名稱: |
工學院 - 材料科學工程學系 Materials Science and Engineering |
論文出版年: | 2015 |
畢業學年度: | 103 |
語文別: | 中文 |
論文頁數: | 151 |
中文關鍵詞: | 奈米粒子 、發光元件 |
外文關鍵詞: | Nano-particles, Light Emission Devices |
相關次數: | 點閱:3 下載:0 |
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本論文主要研究為奈米粒子整合於發光元件的製程與特性,其中包括奈米粒子的合成,以及奈米粒子應用於光電元件的電荷傳輸層、發光層等等,進行元件製程與特性分析,進而優化元件效率。
第二章節,介紹有機發光二極體 (OLED) 的基本工作原理和量測原理,回顧OLED元件光取出的一些方式,並對表面電漿效應作進一步研究。在一般濕式製程的OLED元件中,發現於電洞注入層摻雜金奈米粒子能增加元件電流密度和亮度,但金奈米粒子摻雜濃度太低,使元件效率增益有限。
第三章節,我們使用具有可量產性、產物均一性、低成本等優勢的化學溶膠法合成氧化鋅、氧化鈦奈米粒子。優化化學合成和薄膜製程的參數,將氧化鋅奈米粒子導入有機光伏元件中,能量轉換效率為8.7%,而氧化鈦奈米粒子導入鈣鈦礦太陽能電池中,能量轉換效率為13.2%,高效率的元件表現顯示出金屬氧化物奈米粒子應用於光電元件的潛力。
第四章節,我們使用自行合成之氧化鋅奈米粒子作為電子傳輸材料,挑選具有高量子產率 (quantum yield, QY) 的綠光硒化鎘 (CdSe) 量子點,外殼層包覆硫化鋅 (ZnS),製作反結構量子點電激發光二極體,因氧化鋅奈米粒子薄膜表面形貌粗糙,會產生漏電且有非量子點本身的放光出現,經優化後達0.84 cd/A、0.28 lm/W、0.34% (external quantum efficiency, EQE) 的元件表現。此外,使用核心/殼層具有化學成份梯度的CdZnSeS量子點,改用摻雜Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) 於量子點溶液的方式,進行正結構的製作,發現量子點傾向於浮出TCTA表面,產生垂直相分離 (vertical phase seperation),精準調控量子點濃度優化元件,並選用能階較匹配的電子傳輸材料4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPM),有助於電子電洞的平衡,達到31.5 cd/A、28.6 lm/W、7.5% (EQE) 的元件表現。
第五章節,分別使用注射泵浦和自動噴塗機以化學溶膠法製程鈣鈦礦量子點,發現自動噴塗機可合成出具有更高量子產率的綠光CH3NH3PbBr3量子點,並以CH3NH3PbBr3量子點作為發光層製作量子點電激發光二極體。
In this thesis, we focus on the fabrication and characteristics of light emission devices with nano-particles (NPs), including synthesis of nano-particles and their application of charge transporting layer and emission layer in optoelectronics. The fabrication processes were further optimized to improve the device efficiency.
In the introduction, we briefly introduce the nano-particles for optoelectronics and their synthesis methods.
In the second chapter, we introduce the operating principles and measurement methodology of organic light-emitting diodes (OLEDs). We review some light extraction methods of OLEDs and focus on the surface plasmonic effect. In a typical solution-processed OLED structure, we gained enhanced current density and luminance via doping gold nano-particles in hole injection layer, but the doping concentration of metal nano-particles was too low, leading to a trivial enhancement in device efficiency.
In the third chapter, we utilized the chemical colloidal method, which has advantages of mass-production, reproducibility of products and low fabrication cost, to synthesize ZnO and TiO2 NPs. By optimizing chemical synthesis and thin film process parameters, organic photovoltaics (OPV) with ZnO NPs delivered a PCE of 8.7%. Perovskite solar cell with TiO2 NPs showed a PCE up to 13.2%. The excellent performance imply a promising potential of using metal-oxide NPs for optoelectronic application.
In the fourth chapter, we integrated the home-made ZnO NPs and high quantum yield (QY) green CdSe@ZnS quantum dots (QDs) to fabricate quantum dot light-emitting diodes (QLEDs). Due to the roughness issue of ZnO NPs thin film, leakage current and unexpected blue emission were observed. Optimized device showed a current efficiency of 0.84 cd/A, a power efficacy of 0.28 lm/W, and an external quantum efficiency (EQE) of 0.34%. The CdZnSeS QDs with chemical composition gradient were further studied. Colloial CdZnSeS QDs were blended with Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) as emission layer of the device. Vertical phase separation was observed between QDs and TCTA. The optimization of QLED via changing the QDs doping concentration and selecting the suitable electron transporting material 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPM) was performed and the champion device showed a current efficiency of 31.5 cd/A, a power efficacy of 28.6 lm/W, and an EQE up to 7.5%.
In the fifth chapter, we utilized a syringe pump and an automatically spray coater to synthesize colloidal perovskite QDs. Higher QY value of perovskite QDs (75.6%) was observed by utilizing our new method compared to traditional synthesis techniques. We also demostrated the preliminary results of QLED with colloidal perovskite QDs.
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