能發光最美 電激發光高分子材料(PLED) 國立成功大學 化工系 陳 雲 液晶高分子材料、高分子奈米材料、聚氨酯材料

Presentation on theme: "能發光最美 電激發光高分子材料(PLED) 國立成功大學 化工系 陳 雲 液晶高分子材料、高分子奈米材料、聚氨酯材料"— Presentation transcript:

1 能發光最美 電激發光高分子材料(PLED) 國立成功大學 化工系 陳 雲 液晶高分子材料、高分子奈米材料、聚氨酯材料

2 PLED的研究始於1990年英國劍橋大學Friend等人的研究，發現共軛高分子可做為發光二極體材料，並將Poly(p-phenylene vinylene)(PPV)製作成有機電激發光元件，其結構為ITO/PPV/Ca，此元件發黃綠光。 PLED具備了自發光、高應答速度、視角廣、省電、厚度薄、可撓曲、高亮度、可全彩化等優點。

3 New Flat Panel Display:
* Organic light-emitting diodes (OLED) * Polymer light-emitting diodes (PLED) Organic light-emitting diodes (OLED) and Polymer light-emitting diodes (PLED) are two potential luminescent materials for flat panel display in the near future. They show many advantages over current thin film transistor display LCD such as self emission, wide view angle, simple manufacturing process, and many others. Here are some small-sized display panels that have been commercialized recently. For example, this is PDA from Ritek Display of Taiwan, and ……

4 OLED LCD

5 Introduction * EL Materials S2 * Photoluminescence (PL)
* Electroluminescence (EL) * EL Materials S2 S1 T1 hn So Metal cathode Emitter ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ⊕ ITO anode Photoluminescence is the radiation emitted as a result of relaxation from singlet photoexcited molecule to ground state. Similarly, the excitation of luminescent molecules can also be aroused by an electric potential. Using single layer OLED device as an example, under the drive of electric field the electron inject from metal cathode and the hole inject from anode, usually transparent ITO glass. They combine in the emitting layer to form as exciton and then relaxes to the ground state by emitting light. The electroluminescent materials are roughly divided into low molecular weight compounds and polymers. For most conjugated polymers, electron injection barrier is higher than hole injection barrier. This imbalance in charge injection is usually solved by multilayer strategy. Glass Structure of Single Layer OLED

6 發光效率 LUMO Cathode HOMO Anode

7 發光元件用材料  Metal chelates  Organic chromophores
1. Low molecular weight materials: (vacuum deposition)  Metal chelates  Organic chromophores Characteristics: higher efficiency, higher brightness, lower mechanical strength. 2. Polymers: (spin coating or ink-jet printing)  Fully conjugated polymeric system  Main chain polymers with isolated chromophores  Side chain polymers with linked chromophores  Polymers blending with low molecular weight materials Characteristics: unique processability, mechanical flexibility, few recrystallization processes.

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9 目前主要研究領域: 合成新型電激發光高分子材料，探討其結構與發光特性之關係，並製備發光二極體元件探討其光電性質。
製備電激發光高分子奈米複合材料，探討奈米環境對發光特性的影響。 樹枝狀發光高分子(Dendrimer)的分子設計與製備，探討樹枝狀結構對改善發光高分子因凝集所造成光電特性降低的可行性。 利用活性自由基聚合法製備側鏈型電激發光高分子材料，探討結構與光電特性之間的關聯。

10 )n ( Isolated EL Copolymers o o Al HTS or EL Al ETS or EL ITO ITO
Hole transport / Emitting chromophore Electron transport / Emitting chromophore o )n ( o Al Θ HTS or EL Al In order to explain the mechanism more clearly, I use this graph to represent the combination of both electron- and hole transporting segments into backbone simultaneously. Under electric potential, electron inject into LUMO of electron transporting segments and hole inject into HOMO of hole transporting segments. In other words, they select the lowest energy barrier to jump into copolymers. Therefore, energy barriers of both charges are reduced. ITO ITO ETS or EL 

11 Current Density (open)-Voltage-Luminance (solid) characteristics of single layer LED device [ITO/P1(100 nm)/Al].

12 陳 雲 EL max = 425 nm EL max = 480 nm EL max = 452 & 550 nm

13 Conjugated EL Copolymers
Current Density-Voltage-Luminance characteristics of single layer LED device (ITO/P2/Al).

14 電激發光高分子材料的發展 發光效率的提高 材料分子設計, 凝集的防止, 元件設計,… 磷光發光材料(75%) 紅光材料的開發 發光壽命的提昇
照明及光源應用