由於資訊產業的發展，人們對於顯示器的需求日漸增高，雖然陰極射線管(CDT)具有低成本及好的影像品質，但它卻具有了太大或太重的缺點。因此，新世代的顯示器必須要具有輕薄的特性。以共軛高分子為主的有機電激發光顯示器(polymer light-emitting diodes (PLED))則以其深厚的潛力吸引了大家的目光。而因為共軛高分子材料對於製程的環境非常的敏感，所以有非常多的研究是針對如何改善元件的效率跟亮度。在這篇論文中，有兩種熱效應將會被探討，其一是在蒸鍍陰極金屬之前退火，另外一種則是在蒸鍍陰極金屬之後退火。我們將可以得到當退火的溫度在靠近但未超過發光材料的玻璃轉移溫度時，將會改善表面的粗糙度及長鏈的方向而得到最好的效率。
　　
　　首先，以ITO/PEDOT:PSS/DBPPV/Ca/Al為基本結構。PEDOT:PSS是當做電洞傳輸層，而DBPPV則是當作發光層，其中，DBPPV的玻璃轉移溫度大約是在120°C ~130°C之間。當前退火(pre-annealing)的時候，將會發現退火在剛好低於玻璃轉移溫度的120oC時，效率將會提升到2.58CD/A，而當元件退火的溫度是室溫、90°C、150°C和180°C時，效率則是2.1、1.98、1.91和1.74 cd/A，這是由於退火在120oC會改變長鏈的指向使得再結合的效率變好。另外，前退火(pre-annealing)的溫度在玻璃轉移溫度以下時，對於起始電壓和發光頻譜影響不大。 當元件前退火在室溫、90°C、120°C、150°C和180°C時，起始電壓為2.9V、3.0V、3.0V、3.48V和3.6V；發光頻譜的主峰為524nm、527nm, 530nm、550nm和545nm。而當後退火(post-annealing)的溫度在剛好低於玻璃轉移溫度的120oC的時候，效率將會比前退火(pre-annealing)的2.58CD/A提升到3.04CD/A。這是由於後退火(post-annealing)會增加發光層與陰極金屬接面的附著力，使得電子注入的效率變好；另一方面是在後退火(post-annealing)後，金屬離子會少量擴散至發光層，使得高分子長鏈的指向改善將會稍微改善電子的注入而使得整體的效率變好。在經過後退火(post-annealing)在120oC的元件，最大的亮度為 30871 cd/m2@8.89V 105mA。

　　By the development of the intelligent industry, people have more require for the monitor. Although the CRT is low-cost and good image quality, the CRT is too big and too heavy. Therefore, the new flat panel displays (FPD) have to be thinner and lighter. In this age, polymer light-emitting diodes (PLED) that are based on conjugated polymers have attracted much attention because of their potential applicability to large-area flat panel displays (FPD). Because polymeric materials are known to be sensitive, therefore, various approaches have been explored to improve the device efficiency and luminescence. In this work, an effect of thermal treatment before cathode deposition and post cathode deposition are presented for the purpose of achieving a high efficiency Polymer light-emitting diodes by change the roughness and the chain intensity.
　
　　At first, the devices had been made as ITO/PEDOT:PSS /DBPPV/Ca/Al. The PEDOT:PSS served as HTL and DBPPV served as EL. And, the glass transition temperature of DBPPV was about 120°C ~130°C. On the one hand, the device pre-annealed at 120oC had been demonstrated to have better performance than other pre-annealed devices. For example, the current efficiency was 2.58CD/A of the pre-annealed at 120°C device, just below the Tg, while the devices annealed at RT, 90°C, 150°C and 180°C is only 2.1, 1.98, 1.91 and 1.74 cd/A, respectively. And, there were a little influence for the turn-on voltage and spectrum when pre-annealed temperature below Tg. For example, the turn-on voltage was 2.9V, 3.0V, 3.0V, 3.48V, 3.6V while the devices pre-annealed at RT, 90°C, 120°C, 150°C and 180°C and the main EL peak were 524nm, 527nm, 530nm, 550nm and 545nm. On the other hand, the device post-annealed at 120oC has the best performance than the device pre-annealed at 120oC. For example, the current efficiency was 3.04CD/A of the post-annealed at 120°C device. It was considered have two reasons. The first is post heat treatment may improve the adhesion of the polymer/electrode interface which made for the effective injection of an electron. The other is on the cathode side, the metallic atoms may diffused into the polymer surface. So the orientation of the polymer chain may have little effect to electron injection. Therefore, the post-annealed EL devices give off more bright light at high electric fields than pre-annealed one. And, the maximum luminance is 30871cd/m2 @ 8.89V 105mA.

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