連結式有機白光二極體的載子產生效應之研究

連結式的有機發光二極體以其穩定與長壽命的特性所聞名，因而是最有可能被運用在未來的顯示或是照明的用途上。即便連結式的有機發光二極體以發展相當長的一段時間，仍有些重要的議題尚未被明確解釋。在這篇論文中，我們將利用一個二極體的載子產生層來製作我們的連結式的有機發光二極體。我們會清楚的定義元件的起始電壓並探討其與元件結構的關係。另外，藉由直接對連結式的有機發光二極體進行阻抗的量測，我們發現在相位上有一個特別的轉折，這個轉折不儘與發光的起始以及載子產生層的參雜濃度有關，更被認為是對載子產生機制的直接證據。

關鍵字

有機發光二極體；連結式有機發光二極體；載子產生；阻抗量測；白光

並列摘要

Tandem organic light emitting diodes (tandem OLEDs) are known for the outstanding color quality as well as the enduring operation lifetime and therefore exhibit a great potential to be the next generation display and solid state lighting. Tandem OLEDs have come a long way since their first introduction but there are still some issues that have yet been clarified or well explained. In this thesis, we demonstrate a tandem white light OLED with a p-n junction charge generation layer (CGL). As for the physical mechanisms, we will first clarify the definition of turn-on voltage in a more physical way and then discover the relationship between the architectures of devices and their turn-on voltages. Interestingly, the turn-on voltages of tandem OLEDs are found to be the sum of those of their single OLED units. Besides, the interconnecting layers surprisingly exhibit selectivity in charge transportation and therefore play a very important role in determining the performance of those intermediate devices. Most importantly, by applying impedance measurement directly on tandem OLEDs, a unique transition in phase characteristics, which relates to the turn-on of luminance and the doping ratio in CGL, is revealed at a very first time to be the direct evidence of charge generation effect. Generally speaking, tandem OLEDs seem to possess the features of connection in series to some extents by judging the large turn-on voltage and the greatly enhanced current efficiency which are both the sum of those of the OLED units. However, after the turn-on, tandem OLEDs behave like multilayer devices and show a slowly rising phase characteristics as compared to OLEDs connected in series with electric wires. This demonstrates the functions of charge generation layers, which are not just an electric connection, but provide the electron and hole pairs to the single OLED units connecting to them.

並列關鍵字

Organic light emitting diodes ； Tandem OLED ； Charge generation ； Impedance Measurement ； White light

參考文獻

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國際替代計量

連結式有機白光二極體的載子產生效應之研究

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