Fabrication and Measurement of Organic Light-Emitting Devices
Date Issued
2006
Date
2006
Author(s)
Huang, Bo-Chao
DOI
en-US
Abstract
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.
Subjects
有機發光元件
封裝
載子遷移率
oled
passivation
mobility
Type
thesis