互溶檢驗純刮刀溶液製程製作有機發光二極體

Examine the mutual dissolution to develop small-molecule organic light-emitting diodes by blade coating

劉益倫

指導教授 ： 洪勝富

國立清華大學/電機資訊學院/光電工程研究所/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00263

摘要

本論文將以純溶液製程製作高效率有機發光二極體，但溶液製程中往往因為互溶的影響而導致某層無法順利成膜，即使成膜也許會因互溶影響而使元件效率變差．一般在做有機發光二極體時，電子傳輸層仍採用蒸鍍製程，但本實驗室有機層皆採用刮刀溶液製程使其成本降至最低．而為了解決互溶問題，利用反應式離子蝕刻機 (RIE) 製造明顯的邊界後塗佈有機薄膜來觀察邊界的互溶現象，甚至用最直觀的判斷方法利用表面輪廓儀 (ET 4000) 量測薄膜厚度以及用原子力顯微鏡 (atomic force microscope AFM) 檢驗表面粗糙度來確認整體厚度是否有減少以及表面是否平整，同時也發現在固定其他實驗條件只改變塗佈速度時，速度較快的塗佈速度對於互溶影響會比較小，尤以選擇揮發快的溶劑效果最好．經過這種方法我們成功地製作出完美薄膜製造出多層結構有機發光二極體元件，在我們測試的藍光有機發光二極體元件中，得到有加入電子阻擋層bis[4-(p,p′-ditolyl-amino)phenyl]diphenylsilane (DTASi)的元件仍無法提升元件效率，推測其電子阻擋層材料DTASi或許有本質上的問題而導致有紅移現象．

關鍵字

有機發光二極體 ； 多層結構 ； 溶液製程 ； 電子阻擋層 ； 紅移現象

並列摘要

In this thesis, our team try to develop a blade technique for the making of multilayer organic light-emitting diodes (OLEDs). During the solution process, it has been found that material fail to be coated perfectly due to the mutual dissolution problem. Compared to other processing solution such as small-molecular OLEDs reports, an additional hole blocking /
electron-transport layer, which was made by thermal vapor deposition, our hole-blocking
/ electron-transport layer was made via blade coating method. To solve the mutual dissolution problem, we used the reactive ion etching (RIE) to create a clear boundary, then coating the 2nd organic thin with different solvents. Finally, the phenomenon on the boundary by fluorescence microscopy was observed. The roughness and the thickness of each layer to decrease the inter-miscible were also examined. It was found that when the blade speed was faster, the influence of mutual dissolution was lesser, especially when the good volatility solvent was used. For the Blue multilayer organic light-emitting diodes, the electron-blocking layer material (EBL), bis[4-(p,p′-ditolyl-amino)phenyl]diphenylsilane (DTASi), with high triplet excited state of 2.95 eV, high-lying LUMO level of 2.25 eV was not useful, as a common phenomenon Redshift was observed.

並列關鍵字

organic light-emitting diodes ； multi-layer ； solution process ； electron block layer ； redshift

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