Multilayer transparent electrode consisting of silver alloy layer and metal oxide layers for organic luminescent electronic display device

Abstract

A transparent electrode for an organic luminescent electronic display (OLED) requires higher transmittance and higher electric conductivity to reduce the power consumption, in order that more of the current injected into the display results in luminescence. The authors made transparent conductive multilayer coatings including layers of silver alloy with 1wt% of palladium (Pd) and 1wt% of copper (Cu) (APC) and transparent metal oxide thin film layers for the transparent electrode of an OLED. Indium tin oxide (ITO) and zinc aluminum oxide (AZO) were used as the transparent metal oxides. A multilayer transparent electrode consisting of ITO/APC/ITO and one of AZO/APC/AZO prepared by dc magnetron sputtering achieved transmittance of more than 80% in the wavelength of 450–700nm with sheet resistance of less than 10Ω∕◻. An OLED device employing a multilayer transparent electrode consisting of ITO/APC/ITO emitted light with a higher efficacy than that employing a single layer ITO. On the other hand, the multilayer transparent electrode consisting of AZO/APC/AZO did not emit light even though higher corrosion resistance than ITO/APC/ITO was expected.