化学镀纳米银阴极在聚合物LED中的应用

Study on Polymer LED with Nanosize Silver Cathode by Electroless Plating Method

提出一种基于化学镀方法替代真空蒸发镀制备聚合物发光二极管（LED）阴极的思路。采用Ag（NH3）2^＋-KNaC4H4O6体系将纳米Ag沉积于MEH-PPV薄膜表面并形成ITO／MEH-PPV／Ag发光二极管。用SEM和XRD表征化学镀银层结构与形态，通过椭偏仪研究MEH-PPV浓度、体积等旋涂条件对其厚度影响的规律，初探发光二极管性能。结果表明，当MEH-PPV浓度为5．5mg·mL^-1，加入量15μL，旋转18s（1800r／s）和30s（3000r／s）时，MEH-PPV厚度能控制在100nm左右；化学镀Ag层晶粒均匀致密，尺寸为30-40nm，为典型面心立方结构；驱动电压为6V时，发光二极管能发出峰值波长为589nm的桔红色光。

An electroless plating method is proposed for preparing the cathode of ITO/ MEH-PPV/Ag LED in order to overcome the limitation of vacuum evaporation deposition. The ITO/MEH-PPV/Ag LED was fabricated by plating silver to the surface of MEH-PPV layer on ITOsubstrate in Ag（NH3）2^＋-KNaC4H4O6 · 4H2O（Rochelle salt） solution, the thickness of MEH-PPV layer in different concentration and volume were analyzed by ellipsometer. Structure of silver film was characterized by SEM and XRD, the performance of LED was primarily evaluated. The result shows that thickness of MEH-PPV film is 100 nm when the concentration and volume of MEH-PPV solution are 5.5 mg · mL^-1 and 15 μL, respectively, as well as spin time is 18 s（1 800 rpm） and 30 s（3 000 rpm）. The electroless plating silver layer is very uniform, there is a typical structure of FCC with an average size of 33.4 nm. The LED device can emit orange light with a 589 nm emitting peak with the driving voltage of 6 V. It＇s feasible that the electroless plating method used for preparing the cathode LED.