以三氧化鎢奈米柱陣列作為電子傳輸層之有機/無機混成發光元件

Abstract

在本研究中，我們結合了三氧化鎢奈米柱陣列與乙氧基化聚乙烯亞胺作為電子注入層以製備反結構發光元件並提升其亮度與電流效率。採用溶液凝膠法與水熱法在氧化銦錫(ITO)基板上製備不同型態之三氧化鎢奈米結構。再引入乙氧基化聚乙烯亞胺電子注入層於三氧化鎢奈米結構與發光層之間，藉此提升電子遷移率並獲得較長之螢光生命週期。用水熱法成長之三氧化鎢奈米結構在400–700 nm之可見光波段之穿透率高於90%。製作元件結構為ITO/WO3 nanostructures/PEIE/MEH-PPV/PEDOT:PSS/WO3 film/Au之反結構發光元件，最佳元件效果為使用長度300 nm之WO3奈米柱陣列，其最大亮度及電流效率各為3,079 cd/m2及0.22 cd/A，相較於其他奈米結構或較長之奈米柱，其作為電子傳輸層而言具有更佳的元件效益。

In this research, we prepared inverted light-emitting devices with improved luminance and current efficiency by combining tungsten trioxide (WO3) nanorod arrays and polyethylenimine ethoxylated (PEIE) buffer layer. Different types of WO3 nanostructures were grown on the indium-tin oxide (ITO) substrates by sol-gel process and hydrothermal method. PEIE buffer layer was introduced between WO3 nanostructures and emissive layer to improve the electron mobility and obtain the longer fluorescence lifetime. The prepared WO3 nanostructures show high transmittance over 90% in the wavelength of 400–700 nm. Inverted devices with the configuration of ITO/WO3 nanostructures/PEIE/poly(2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/WO3 film/Au were constructed and evaluated. The best device based on WO3 NAs with height of 300 nm showed a max brightness of 3,079 cd/m2 and current efficiency of 0.22 cd/A, evealing much higher performance compared with those using WO3 nanostructures or nanorods with longer lengths as electron transporting layers.