有機發光元件的研製與量測

Fabrication and Measurement of Organic Light-Emitting Devices

黃柏超(Bo-Chao Huang)

指導教授 ： 吳忠幟

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01512

摘要

有機發光元件在近幾年來受到廣泛的研究和討論，因為它可以應用到高效率、大面積、可撓曲的全彩顯示器上。然而，有機發光元件中所使用的有機材料易受到周圍環境中水及氧氣的影響。而且若覆蓋在有機層上的電極也氧化， 則有機發光元件的光電特性會遭到嚴重的損壞。為了要增加有機發光元件的壽命，我們必須防止水及氧氣擴散至元件裡面。在元件上形成一層保護層可以使元件不受到大氣中水及氧氣的破壞。在這個論文中，我們使用低溫電漿輔助化學氣相沈積系統(PECVD)沉積a-SiNx，還有室溫真空沉積的Parylene來當作有機發光元件的保護層。我們使用不同保護層沈積條件及結構沉積保護層在有機發光元件上。然後量測這些使用不同保護層條件的元件光電特性及外觀隨時間的變化。我們發現若我們在沈積a-SiNx使用較高的沉積溫度和較低的沉積功率的話，保護層抗水氧的能力會比較好。除此之外，在相同的厚度下，多層結構的保護層保護的效果會比單層結構來的好。
Frequency-domain response technique被用來量測有機發光元件中有積材料的載子遷移率。當我們施加一個連續周期性的方波電壓在有機發光元件，如果我們增加此方波訊號的頻率時，有機發光元件發光的強度會逐漸減少。在某個高頻率信號下，許多的載子會來不及到達發光層，因此發光的強度會快速地減少。所以我們可以利用這種特殊的頻率限制來決定載子的遷移率。在這個論文中，我們成功的量測出m-MTDATA電洞的載子遷移率。

關鍵字

有機發光元件 ； 封裝 ； 載子遷移率

並列摘要

Organic light-emitting devices (OLEDs) technology has been the subjects of intense investigation in recent years due to their applications in efficient, large area, flexible and full color displays. However, the organic materials used to form Organic light-emitting devices (OLEDs) are susceptible to moisture and oxygen. Furthermore, oxidation on the electrode, which is formed on the light-emitting layer, may deteriorate the EL diode properties. To increase the lifetime, it is essential to protect the diode from moisture and oxygen diffusion into the devices. The formation of a passivation layer on the diode may offer protection from atmospheric degradation. In this thesis, we used low-temperature Plasma-enhance chemical vapor deposition (PECVD) to deposit hydrogenated amorphous silicon nitrite (a-SiNx: H) films and room-temperature vacuum deposition of Parylene as my passivation materials. We used different deposition condition and passivation structures to form passivation layers on OLEDs. Then we measured the photoelectrical characteristic and stability of OLEDs using different passivation layers. We found that the lower deposition power and the higher deposition temperature we used to deposit a-SiNx: H films, the better ability to resist moisture and oxygen the passivation layers had. Besides, the protective ability of multilayer passivation was better than single-layer passivation.
Also, in this thesis, the frequency-domain response technique was used to investigate the carrier mobility of organic materials in OLED structures. When we increased the frequency of square voltage pulse waves applied to OLEDs, the electroluminescence (EL) intensity decreased. At certain high frequencies, if the half-cycle duration of pulse waves was less than the time needed for the charge carriers to reach the emitting layer at a particular field, the EL intensity dropped rapidly. Thus, we could determine the mobility from the characteristic frequency limit. In this thesis, we successfully measured the hole mobility of m-MTDATA (a hole transport material) with this method.

並列關鍵字

oled ； passivation ； mobility

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