新穎藍色發光體的設計與合成及其應用在有機發光二極體的性質研究

Abstract

摘要 本論文是一系列藍色螢光體的合成，嘗試合成下列幾種化合物：2-[10-(3,5-Diphenyl-2-thienyl)-9-anthryl]-3,5-diphenylthiophene ( DPTA )、2-(10-Benzo[b]thiophen-2-yl-9-anthryl) benzo[b]thiophene ( DBTA )、3-Phenyl-2-[10-(3-phenylbenzo[b]thiophen-2-yl)-9-anthryl]benzo[b]thiophene ( DPBTA )。在合成藍色螢光主發光體的方面朝兩大方向進行：（1）增加分子的立體阻礙，避免分子之間的堆疊造成螢光強度的降低；（2）增加分子的共軛度，此舉可以調節螢光體的發光顏色。由於有機合成上所遭遇的困難，我們僅合成出DBTA。另外我們成功的合成了不對稱的藍色主發光體，包含了以下幾個化合物：2-(9-Anthryl)benzo[b]thiophene ( BTA )、2-(9-Anthryl) -3-phenylbenzo[b]thiophene ( PBTA )、2-[(9-Anthryl-10-(2-naphthyl)] benzo[b]thiophen ( BTNA )。 在液態螢光的測量方面，我們以β-DNA為標準品，與上述我們合成的四種化合物做比較。這四種化合物的相對量子效率都不高，其中只有BTNA較高，約為54 %。 在固態螢光的測量方面，由於DBTA的螢光效率太低，我們只測量β-DNA、BTNA、BTA、PBTA的固態螢光，發現這四個化合物在固態的能量轉移都相當的好，能量能夠完全地轉移至摻雜物上。 在第一次製作元件時，我們參考標準元件構造來製作。經過測量之後，我們發現元件並不是發出藍光，而是發出AlQ3的光。 經過HOMO與LUMO的計算，我們在發光層和AlQ3之間加上BCP，發現EL的放射波長已經藍位移至490 nm，顯示加入BCP可以有效將電子電洞的再結合侷限在發光層中。不過，這個元件在20 mA / cm2的電流密度下，電壓卻高達38 V。這是因為電子無法有效地從AlQ3層傳輸至β-DNA層，且BCP又不是一個良好的電子傳輸材料。本實驗室正在做一連串關於藍光元件的改良及BCP化合物的選擇的實驗，期望往後能有一個令人滿意的結果。

Abstract In this thesis, we tried to synthesize benzo[b]thiophene substituted compounds: 2-[10-(3,5-Diphenyl-2-thienyl)-9-anthryl]-3,5-diphenylthiophene ( DPTA ), 2-(10-Benzo[b]thiophen-2-yl-9-anthryl)benzo[b]thiophene( DBTA ), 3-Phenyl-2-[10-(3-phenylbenzo[b]thiophen-2-yl)-9-anthryl]benzo[b]thiophene ( DPBTA ), but only the synthesis of DBTA was achieved. In addition, we also synthesized 2-(9-Anthryl)benzo[b]thiophene ( BTA ), 2-(9-Anthryl)-3- phenylbenzo[b]thiophene ( PBTA ), 2-[(9-Anthryl-10-(2-naphthyl)] benzo[b]thiophen ( BTNA ) . In solution PL, we use β-DNA as the reference, and our compounds are compared with β-DNA. β-DNA is the highest fluorescent compound among them. BTNA has the highest quantum efficiency ( 54 % ) among the four synthesized compounds. In solid PL, the dopant ( TBPe ) was co-evaporated in various concentrations with our four synthesized hosts respectively. The results revealed a good energy transfer from the hosts to the dopant TBPe. Cell device was fabricated in standard structure of device. We found that the emission of the device is green light. After calculating HOMO and LUMO values of the various hosts, we added the BCP layer between emitting layer and AlQ3 layer. The BCP effectively confined the recombination of holes and electrons in the emitting layer. Therefore, we successfully made the device which emits a good blue light with the emission peak locates at 490 nm. The voltage of this device at 20 mA / cm2 is up to 38 V. It is because that the electrons can not be effectively transferred from AlQ3 layer to emitter. We expect that the modification of blue emission device can be achieved by selecting suitable materials.