具有高反射率下電極之上發射型有機發光元件

對於上發射型（top-emitting）有機發光元件（organic light-emitting devices, OLEDs）來說，若元件的下電極陽極具有較高的反射率，則可增加元件的發光強度及特性。在所有的金屬材料之中，銀具有最高的反射率，但是由於其功函數與常用的有機材料不匹配，所以對有機發光元件來說，銀並不適合作為元件的陽極。在本論文中，我們報導一對銀表面處理而產生氧化銀薄膜之陽極電極結構，此陽極電極在有機發光元件中具有良好的電洞注入特性且同時保有極高的反射率，當我們應用此陽極電極製作出上發射型有機發光元件，其元件電特性與傳統利用氧化銦錫（indium tin oxide, ITO）作為陽極之下發射型元件相當，甚至在光色及效率表現方面，此上發射型元件具有更好之特性。

A high-reflectivity bottom anode is essential for high-performance top-emitting organic light-emitting devices (OLEDs). Ag has the highest reflectivity for visible light among all metals, yet its electronic properties are not ideal for anodes of OLEDs. In this article, we report that by inducing a thin silver oxide at the surface of Ag, hole injection from Ag anodes into OLEDs is largely enhanced yet with rather high reflectivity retained. Top-emitting devices using such surface-modified Ag anode show device characteristics competitive with those of a bottom-emitting device using the indium tin oxide anode.