RT - Journal Article T1 - Thin-film Encapsulation of Organic Light-Emitting Diodes Using Single and Multilayer Structures of MgF2, YF3 and ZnS JF - ijop YR - 2013 JO - ijop VO - 7 IS - 1 UR - http://ijop.ir/article-1-124-en.html SP - 11 EP - 18 K1 - MgF2 K1 - OLEDs K1 - Thin-film encapsulation K1 - YF3 K1 - ZnS AB - In this research, the lifetime of green organic light emitting diodes (OLEDs) is studied using four passivation layers. To encapsulate the OLEDs, MgF2, YF3, composed of alternating MgF2/ZnS and YF3/ZnS layers were grown by thermal vacuum deposition. Measurements show that the device lifetime is significantly improved by using YF3 and ZnS as passivation layers. However, diodes encapsulated by MgF2/ZnS and YF3/ZnS nano-structures show a highly efficient gas diffusion barrier that results in a longer lifetime of the devices. The half lifetime of the green OLEDs reached 1200 minutes using YF3/ZnS layers. The electroluminescence (EL) and current-voltage characteristics of the devices were also examined to compare the electrical and the emissivity properties of the devices before and after encapsulation. This simple and inexpensive thin-film encapsulation method would be potentially employed to capsulate top emitting OLEDs and flexible OLEDs due to their good performance and easy fabrication. LA eng UL http://ijop.ir/article-1-124-en.html M3 ER -