光電元件封裝材料之製備與改善研究

Abstract

本論文研究各種紫外光硬化高分子複合膠材（聚氨基甲酸脂-丙烯酸脂/氧化矽（PU-acrylate/Silica = 90 wt.%/10 wt.%）、矽氧樹脂-丙烯酸脂/氧化鋁（Silicone-acrylate/Alumina = 90 wt.%/10 wt.%）、環氧樹脂-丙烯酸脂/氧化矽/Invar合金（Epoxy-acrylate/Silica/Invar= 35 wt.%/50 wt.%/15 wt.%）之製備，並將其應用至有機發光二極體（Organic Light-emitting Devices，OLEDs）、有機太陽能電池（Organic Solar Cells，OSCs）與發光二極體（Light-emitting Diodes，LEDs）之封裝。OLED之封裝部分之研究發現藉由調控氟化鋰（Lithium Fluoride，LiF）的厚度並以自製的封裝膠進行封裝能阻擋空氣中的水氣與氧氣進入OLEDs中，其可成功地提升OLED的壽命達未封裝的18倍。OLED的研究中亦建構了低起始電壓（Turn-on Voltage = 3 V）、高亮度（於9 V驅動下可達4850 cd/m2），顏色/亮度可調之OLEDs，其結構為ITO Glass/naphthyl phenyl benzidine (NPB; 80 nm)/4,4’-bis (diphenylvinylenyl)-biphenyl (ADS082BE; 35 nm)/1,3-bis [2-(2,2’-bipyridine-6-yl)-1,3,4-oxadiazo-5-yl] benzene (Bpy-OXD; 20 nm)/ tris-[8-hydroxy-quinoline]aluminum (Alq3; 50 nm)/(LiF; 3 nm)/Aluminum (Al; 80 nm)，其電致變色性質（光色、發光強度等）可藉由調整NPB/ADS082BE/Bpy-OXD的厚度與驅動電壓進行調控。OLED與LED元件壽命之研究顯示自製的UV硬化Silicone-acrylate封裝樹脂具有優異阻氣性，可將OLED與LED元件的半衰壽命（Half-lifetime）自未封裝之9小時與2400小時提高至98小時與18300小時。 本論文研究同時製備高熱穩定性、適度接著強度與優異阻氣性的UV硬化環氧樹脂-壓克力奈米複合膠材（Epoxy-acrylate Nanocomposite Resins），膠材中除奈米氧化矽填充物之外，並添加Invar合金，以提高其阻氣性並減低了於UV硬化後的收縮問題。此一膠材被應用OSCs的封裝，實驗結果顯示其可有效阻擋空氣中水氣與氧氣入侵元件中，而提升OSCs元件的壽命。 本論文同時研發以聚乙烯接枝甲基丙烯酸缩水甘油酯（Polyethane-graft- Glycidylmethacrylate，PE-g-GMA）為相容劑（Compatibilizer）之聚苯硫醚/聚乙烯對苯二甲脂（Polyphenylene Sulfide/Poly(ethylene terephthalate)/PE-g-GMA，PPS/PET/PE-g-GMA (wt./wt./wt.)=100/50/12.5） 與聚苯硫醚/尼龍6,6/玻纖合金（PPS/Nylon 6,6/Glass Fiber Alloy/ PE-g-GMA(wt./wt./wt./wt.) =100/50/45/12.5）的成型製程以製作LED之耐溫構裝反射杯體，PE-g-GMA含量對高分子合金之影響以及製成價廉、高反射性質之耐溫構裝反射杯體之可行性亦被分析之。

This thesis studied the preparation of various ultraviolet (UV)-curable polymeric composite resins (i.e. PU-acrylate/silica (weight ratio = 90 wt.%/10 wt.%), silicone-acrylate/Alumina (weight ratio = 90 wt.%/10 wt.%) as well as epoxy-acrylate/silica/Invar (weight ratio = 35 wt.%/50 wt.%/15 wt.%) and their applications for the packaging of organic light-emitting devices (OLEDs), organic solar cells (OSCs) and light-emitting diodes (LEDs). In the part of study relating to OLEDs, the lifetimes of devices were successfully enhanced by modulating the LiF thickness and utilizing the UV-curable silicone-acrylate adhesives for encapsulation. It was found that the LiF and lab-made encapsulating adhesives can effectively block the invasion of moisture as well as oxygen in the atmosphere into the OLEDs so that an 18-folds increment of lifetimes was achieved after encapsulation. A low turn-on voltage (3 V), high luminance (4850 cd/m2 at 9 V), color/luminance tunable OLED with device structure as ITO glass/naphthyl phenyl benzidine (NPB; 80 nm)/4,4’-bis(diphenylvinylenyl)- biphenyl (ADS082BE; 35 nm)/1,3-bis[2-(2,2’-bipyridine-6-yl)-1,3,4-oxadiazo-5-yl] benzene (Bpy-OXD; 20 nm)/tris-[8-hydroxy- quinoline]aluminum (Alq3; 50 nm)/lithium fluoride (LiF; 3 nm )/aluminum (Al; 80 nm) was successfully fabricated in this study. Its electroluminescent properties (e.g., hue, luminescent intensity, etc.) could be modulated by the manipulation for the layer thickness of NPB/ADS082BE/Bpy-OXD and the applied bias. In addition, the UV-curable silicone-acrylate encapsulating resin exhibited excellent gas barrier capability so that the half-lifetimes of OLEDs and LEDs reached 98 and 18300 hrs while those without encapsulation were only 9 and 2400 hrs. The UV-curable epoxy-acrylate nanocomposite resins with good thermal stability, moderate adhesion strength and excellent gas barrier capability were also prepared in this work. In order to improve the gas blocking properties, the Invar alloy was also blended into the resins so as to increase the gas resistance and decrease resin shrinkage after UV curing. Experimental results revealed that introduction of epoxy-acrylate nanocomposite resins could effectively block the penetration of moisture as well as oxygen in the air into the devices and consequently promoted the lifetimes of OSCs. Fabrication of polymeric reflector cups for LEDs by using polyphenylene sulfide/poly(ethylene terephthalate) (PPS/PET) and PPS/nylon 6,6/glass fiber alloys via injection molding process was also presented in this work. In order to enhance their mechanical properties, the compatibilizer, PE-g-GMA, was first developed by grafting the glycidyl methacrylate (GMA) into the low-density polyethylene (LDPE) with initiators by reactive extrusion procedure in a twin screw extruder. PPS/PET and PPS/nylon 6,6/glass fiber alloys with various amounts of PE-g-GMA (PPS/PET/PE-g-GMA (wt./wt./wt.)=100/50/12.5; PPS/Nylon 6,6/Glass Fiber Alloy/ PE-g-GMA(wt./wt./wt./wt.) =100/50/45/12.5) were then prepared and their physical properties as well as feasibilities for the high-brightness LEDs were also analyzed.