Optics and Photonics Society of Iran

In this investigation silicon oxide (SiO) and silicon nitride (Si3N4) bilayers and glass cover were applied as encapsulation cap on glass-based organic light emitting diodes (OLEDs). When Si3N4 layer was deposited on to the OLED structure, the devices showed performance worse than one without any encapsulation. The adverse effects were attributed to the damage caused by reaction species during the Si3N4 sputtering deposition processes. To solve this problem, a SiO interlayer is used to provide effective protection to the OLED structure. Si3N4 thin film deposited by RF-sputtering and SiO thin film deposited by PVD method and both of them prepared in vacuum chamber. After deposition, current-voltage parameter and life time of diode have been measured. Diode luminescence spectra has been investigated. Half- life for the thin films encapsulation OLED estimated 542 hours and for the glass cover encapsulation OLED estimated 1078 hours. Results show life time for the thin films encapsulation OLED is half of glass cover encapsulation OLED.