高效率藍光多層共軛高分子發光二極體

Abstract

共軛高分子發光二極體相較於小分子的優勢在於其可利用溶液製程，此舉可大幅的降低成本，但其效率卻仍遜於小分子。關於效率方面，瓶頸應是溶液製程所引發的互溶問題。雖然文獻上有許多改善的方法，但仍是有許多的缺點。 此研究論文建立在之前學長所研究出的緩衝層技術上，以藍光材料PFO(Poly(9,9-dioctylfluorenyl-2,7-diyl)為發光層，並引入TFB及B.K.兩種材料分別作為電洞傳輸層/電子阻擋層及電子傳輸層/電洞阻擋層，進而製作出三層結構的LED元件，令電子、電洞於發光層內達到最佳的平衡，以發揮此發光材料的最高效益。 而本論文結果中，藍光共軛高分子發光二極體的外部量子效率可達到接近理論極限的4%，電流效益達3cd/A，雖未能超越BP105於本實驗室的紀錄4.2%、7cd/A，但對於原本單層結構僅1cd/A左右的PFO也算是相當的成功。

Compares to the organic light emitting diodes, polymer light emitting diodes is better. It's superiority lies in that it may use solution process. In this way, it may large reduce the cost. About the efficiency aspect, it is not as high as the organic light emitting diodes. The bottleneck should be the mutually soluble which solution process initiates. Though people show a lot of methods in the literature, there are still many shortcomings. This research is based on the buffer layer technology which studied by my school leader. Take blue light PFO(Poly (9,9-dioctylfluorenyl-2,7-diyl) as emission layer, and introduces two kinds of materials, TFB and B. K., as hole transport layer/electron blocking layer and electron transport layer/hole blocking layer, then manufactures triple layer PLED part. By doing this may make electron and hole achieve the best balance in emission layer, and also display the highest benefit. The result of this research, the external quantum efficiency (EQE) of blue polymer light emitting diodes may achieve 4% which approaches the theory limit ,and its current efficiency reaches 3cd/A. It has not been able to surmount BP105 which was recorded 42%, 7cd/A in this laboratory, but comparing to the PFO, which was in single layer structure, was only recorded 1cd/A, the result is really successful.