利用刮刀塗佈製程之未改質小分子有機發光二極體

Abstract

以刮刀塗佈技術搭配下方均勻之加熱器以特定溫度加熱及上方均勻之熱風裝置製作多層結構之未改質小分子有機發光二極體，大部分未改質小分子原本是設計給熱蒸鍍製程使用，材料溶解於有機溶劑中濃度約大於 0.5% 即可透過刮刀塗佈製程成膜，可製作長度達 5 cm 左右之均勻固態薄膜。利用刮刀塗佈製作未改質小分子材料的磷光綠光有機發光二極體，以 2,6-bis(3-(carbazol-9-yl)phenyl)pyridine (26DCzPPy) 為主發光體材料、tris[2-(p-tolyl)pyridine]iridium(III) (Ir(mppy)3) 為客發光體材料，搭配適當的電洞傳輸層材料如 4,4',4"-tris-(N-carbazolyl)-triphenylamine (TCTA) 與 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) 可製做出高效率之有機發光二極體，前後兩者效率分別為 38.3 cd/A, 13.8 lm/W 與 41.9 cd/A, 23.4 lm/W。並且在相同元件架構下比較熱蒸鍍與刮刀塗佈製程之效率表現。本研究成果顯示在相同元件架構下以刮刀塗佈方式製作之有機發光二極體幾乎可以達到熱蒸鍍製程製作之元件的效率表現。

Blade coating with substrate heating and hot wind is demonstrated to be a general platform for multi-layer deposition of unmodified small-molecule organic semiconductors. Most unmodified small molecules, originally designed for vacuum evaporation, can be blade coated while the solubility is above 0.5%. High uniformity is achieved for scale over 5 cm. Green devices by blade coating are 2,6-bis(3-(carbazol-9-yl)phenyl)pyridine (26DCzPPy) as the host, tris[2-(p-tolyl)pyridine]iridium(III) (Ir(mppy)3) as the emitter. When 4,4',4"-tris-(N-carbazolyl)-triphenylamine (TCTA) and 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) is used as the hole transporting layers, the efficiencies are 38.3 cd/A, 13.8 lm/W and 41.9 cd/A, 23.4 lm/W, respectively. The optimized organic light-emitting diodes (OLED) structure developed for vacuum deposition can therefore be exactly copied by the low cost blade coating method in solution.