本文關(guān)鍵詞：基于藍光和黃光的白光有機電致發(fā)光器件的研究　出處：《電子科技大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 白光有機電致發(fā)光器件(WOLED) 藍光 黃光 電子傳輸 延遲熒光

【摘要】：有機電致發(fā)光器件(organic light-emitting device,OLED),也稱有機電致發(fā)光二極管,因基于有機材料,故擁有原材料來源豐富、可制備超薄柔性器件和功能千變?nèi)f化等特質(zhì)。近些年,隨著學(xué)術(shù)界與工業(yè)界的研究人員的共同攻關(guān),OLED也被冠以高效率、低成本、可大面積生產(chǎn)等特點,并在信息顯示產(chǎn)業(yè)得到廣泛的應(yīng)用。此外,由于其平面發(fā)光的特性,也被制成白光OLED(white OLED,WOLED),用來做固態(tài)照明光源或液晶顯示器的背光源。利用互補色(藍+黃)或三基色(紅+綠+藍)可以實現(xiàn)WOLED。然而,在走向產(chǎn)業(yè)化的過程中,OLED仍存在器件效率低、發(fā)光亮度低、壽命短、良率低和成本昂貴等問題,所以仍然需要以材料、器件結(jié)構(gòu)和內(nèi)部機理等方面為突破點開展基礎(chǔ)科學(xué)研究。本工作主要針對互補色WOLED器件中存在的以上問題,首先選取一種藍光熒光、兩種藍光磷光和一種藍光延遲熒光發(fā)光材料,制作了四組藍光OLED器件,獲得了最好的藍光OLED器件的性能。與此同時,從新型主體材料和新型器件結(jié)構(gòu)的角度,優(yōu)化了黃光OLED器件的性能,并進行了深入的發(fā)光機理分析。利用藍光磷光發(fā)光材料和黃光磷光發(fā)光材料制備并優(yōu)化了WOLED器件,研究了單層、雙層電子傳輸層對WOLED器件性能的影響。另外,將一種可以發(fā)黃光的熱激活延遲熒光(thermally acticated delayed fluorescence,TADF)發(fā)光材料應(yīng)用于一種有機紫外探測與電致發(fā)光一體化器件,并創(chuàng)新地引入了激子調(diào)控層結(jié)構(gòu),系統(tǒng)研究了不同激子調(diào)控層對該器件的影響,在一定程度上解決了目前有機光電子器件集成度低、生產(chǎn)成本高、性能差的問題。本論文將具體從以下五個方面開展研究:1、研究了基于主客體摻雜發(fā)光層結(jié)構(gòu)的藍光OLED器件性能。選取N,N’-dicarbazolyl-3,5-benzene(mCP)作為發(fā)光層主體材料,采用四種不同類型的藍光發(fā)光材料分別制備藍光OLED器件,其中包括,藍光熒光發(fā)光材料4,4’-bis(2,2’-diphenylyinyl)-1,1’-biphenyl(DPVBi)、藍光磷光發(fā)光材料bis[(4,6-difluorophenyl)-pyridinato-N,C2’](picolinate)iridium(III)(FIrpic)和bis(2,4-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate iridium(III)(FIr6)、藍光TADF發(fā)光材料4,5-di(9H-carbazol-9-yl)phthalonitrile(2CzPN),對這些器件的亮度、發(fā)光效率等指標,以及發(fā)光機理進行分析。研究發(fā)現(xiàn),基于FIrpic的器件由于可以利用了100%的激子發(fā)光,并且能量傳遞充分,因此該器件整體性能最優(yōu),亮度最大值達22680 cd/m2,電流效率最大值為9.72 cd/A,功率效率最大值為5.42 lm/W。2、研究了一種具有三線態(tài)-三線態(tài)湮滅(triplet-triplet annihilation,TTA)性質(zhì)的新型電荷轉(zhuǎn)移態(tài)材料6-{3,5-bis-[9-(4-t-butylphenyl)-9h-carbazol-3-yl]-phenoxy}-2-(4-t-butylphenyl)-benzo[de]isoquinoline-1,3-dione(czphoni)作為主體材料的黃光熒光、磷光和紅光熒光、磷光oled器件的性能及其發(fā)光機理。將黃光熒光發(fā)光材料、黃光磷光發(fā)光材料和紅光熒光發(fā)光材料、紅光磷光發(fā)光材料以不同摻雜濃度分別摻入czphoni主體材料中,制備了四組oled器件,分別詳細研究這些器件的電致發(fā)光性能。我們發(fā)現(xiàn)熒光oled器件和磷光oled器件的外量子效率都超過了它們對應(yīng)的理論值。研究發(fā)現(xiàn),主客體間高效的能量傳遞和通過tta過程的三線態(tài)激子上轉(zhuǎn)換為單線態(tài)激子的作用機制,在熒光oled器件和磷光oled器件起到重要作用。同時,磷光器件的發(fā)光過程還包含載流子直接俘獲形成激子。此外,研究結(jié)果還發(fā)現(xiàn)最優(yōu)化的熒光oled器件和磷光oled器件的客體摻雜濃度都較高,經(jīng)驗證,主體材料czphoni分子上連接的叔丁基團起到了提高czphoni熱穩(wěn)定性和抑制客體材料濃度淬滅的效應(yīng)。3、研究了含有rubrene超薄發(fā)光層的異質(zhì)結(jié)結(jié)構(gòu)激基復(fù)合物界面和異質(zhì)結(jié)結(jié)構(gòu)非激基復(fù)合物界面的性能及發(fā)光機理。采用異質(zhì)結(jié)結(jié)構(gòu)激基復(fù)合物界面、異質(zhì)結(jié)結(jié)構(gòu)非激基復(fù)合物界面,并在這兩種界面中間插入超薄黃光熒光發(fā)光層rubrene,制備了兩類oled器件,并通過優(yōu)化超薄發(fā)光層的厚度,來獲得高性能黃光oled器件。由于激基復(fù)合物是受體材料與給體材料之間形成的電荷轉(zhuǎn)移態(tài),因此激基復(fù)合物有實現(xiàn)tadf過程的能力。研究發(fā)現(xiàn),上述基于激基復(fù)合物的oled器件中,能量傳遞和三線態(tài)激子的上轉(zhuǎn)換是主要發(fā)光機制;基于非激基復(fù)合物的oled器件中,載流子直接俘獲形成激子是主要發(fā)光機制。基于激基復(fù)合物的oled器件得到了18311cd/m2的最大亮度、16.6cd/a的最大電流效率和12.7lm/w的最大功率效率;基于非激基復(fù)合物的oled器件得到了11860cd/m2的最大亮度、17.3cd/a的最大電流效率和8.1lm/w的最大功率效率。4、系統(tǒng)研究了由摻雜層結(jié)構(gòu)藍光和超薄層結(jié)構(gòu)黃光組成的woled器件的發(fā)光機理,以及電子傳輸對woled器件性能的影響。采用mcp和firpic主客體摻雜結(jié)構(gòu)作為藍光發(fā)光層,超薄的(tbt)2ir(acac)作為黃光發(fā)光層,改變firpic的摻雜濃度和(tbt)2ir(acac)的厚度,優(yōu)化了woled器件的效率。研究發(fā)現(xiàn),當(dāng)firpic的摻雜濃度為9wt.%、(tbt)2ir(acac)的厚度為1nm時,器件的啟亮電壓為2.6v,最大亮度為70520cd/m2,電流效率及功率效率的峰值分別為33.3cd/a和25.6lm/w,白光色坐標為(0.364,0.417)。選取四種不同的電子傳輸材料作為woled的電子傳輸層,討論了電子遷移率、能級結(jié)構(gòu)、三線態(tài)能級對woled器件效率、光譜的影響。研究發(fā)現(xiàn),采用tpbi作為電子傳輸層的WOLED器件獲得了不隨外加電壓變化而變化的穩(wěn)定光譜,采用4,7-diphenyl-1,10-phenanthroline(Bphen)的WOLED器件獲得了最高的效率。隨后,引入雙層結(jié)構(gòu)電子傳輸層,即TPBi/Bphen,作為WOLED的電子傳輸結(jié)構(gòu),通過改變TPBi和Bphen的厚度,研究了電子傳輸?shù)目刂茖OLED器件的光譜穩(wěn)定性的影響。當(dāng)TPBi的厚度為20 nm、Bphen的厚度為20 nm時,WOLED有最好的光譜穩(wěn)定性,外加電壓從7 V變化到11 V時,色坐標漂移僅為(-0.003,0.007)。5、研究了將TADF發(fā)光材料應(yīng)用于一種有機紫外探測與電致發(fā)光一體化器件。利用了TADF材料作為光活性層,并創(chuàng)新地引入了激子調(diào)控層結(jié)構(gòu),制備了一體化器件,并系統(tǒng)研究了不同激子調(diào)控層對該器件的影響。研究發(fā)現(xiàn),激子調(diào)控層的能級對一體化器件的載流子傳輸過程有很大的影響。另外,研究也對一體化器件在正向偏壓和反向偏壓下的工作機制進行了分析。結(jié)果表明,在350 nm紫外光照射、-1 V偏壓下,一體化器件的紫外光探測率高達1.4×1012瓊斯;同時,在正向偏壓下,該一體化器件可以實現(xiàn)黃光電致發(fā)光,具有26370 cd/m2的亮度峰值、8.2 cd/A的電流效率峰值。綜上所述,本研究工作為實現(xiàn)基于藍光和黃光的高性能互補色WOLED器件奠定了實驗與理論基礎(chǔ)。同時,一體化器件的開發(fā),為未來有機光電子器件的大規(guī)模低成本生產(chǎn)打下應(yīng)用基礎(chǔ),有望在可穿戴設(shè)備上得到大規(guī)模的應(yīng)用。
[Abstract]:Organic light-emitting device (OLED), also known as organic light-emitting diodes, is based on organic materials, so it has many characteristics, such as rich raw materials, thin ultrathin flexible devices and ever-changing functions. In recent years, with the joint research of academia and industry researchers, OLED has also been characterized by high efficiency, low cost and large area production, and has been widely applied in information display industry. In addition, the white light OLED (white OLED, WOLED) is also made to be used as a backlight for solid-state lighting or liquid crystal displays due to its plane luminescence. WOLED can be achieved by using complementary color (blue + yellow) or three basic color (red + Green + blue). However, in the process of industrialization, OLED still has some problems such as low device efficiency, low luminance, short life, low yield and high cost. Therefore, we need to carry out basic scientific research as breakthrough point in terms of material, device structure and internal mechanism. Aiming at the above problems in complementary color WOLED devices, we first select a blue light, two blue light phosphors and a blue light delayed luminescent material. We made four sets of blue OLED devices, and got the best blue light OLED devices. At the same time, the performance of the Yellow OLED device was optimized from the angle of new main material and new device structure, and the in-depth analysis of the luminescence mechanism was carried out. Blue and white phosphorescent materials and yellow phosphorescent materials were used to prepare and optimize WOLED devices. The influence of single layer and double layer electron transport layer on the performance of WOLED devices was studied. In addition, a yellow light can be thermally activated delayed fluorescence (thermally acticated delayed fluorescence, TADF) luminescent material is applied to a kind of organic UV detection and electroluminescent devices and integration, innovation and the introduction of the exciton regulation layer structure, studied the influence on the exciton control layer in a certain device. The extent of organic optoelectronic devices with low integration, high production cost, the problems of poor performance. This thesis will be studied in the following five aspects: 1. The performance of the blue light OLED device based on the structure of the host and guest doped luminescent layer is studied. Select N, N '-dicarbazolyl-3,5-benzene (mCP) as the emitting layer main material, the use of four different types of blue luminescent materials were prepared by blue OLED devices, including blue fluorescent materials 4,4' -bis (2,2 '-diphenylyinyl) -1,1' -biphenyl (DPVBi), blue phosphorescent material bis[(4,6-difluorophenyl) -pyridinato-N, C2 "] (picolinate) iridium (III) (FIrpic) and bis (2,4-difluorophenylpyridinato) tetrakis (1-pyrazolyl) borate iridium (III) TADF (FIr6), blue light emitting material 4,5-di (9H-carbazol-9-yl) phthalonitrile (2CzPN), brightness and luminous efficiency of these devices and other indicators, and the luminescence mechanism analysis. It is found that the device based on FIrpic can use 100% exciton emission and full energy transfer, so the device has the best overall performance, the maximum brightness value is 22680 cd/m2, the maximum current efficiency is 9.72 cd/A, and the maximum power efficiency is 5.42 lm/W. 2, study with a three - three triplet triplet annihilation (triplet-triplet annihilation, TTA) model the properties of the charge transfer state material 6-{3,5-bis-[9- (4-t-butylphenyl) -9h-carbazol-3-yl]-phenoxy}-2- (4-t-butylphenyl) -benzo[de]isoquinoline-1,3-dione (czphoni) as the main material properties and luminescence mechanism of yellow light and red fluorescence, phosphorescence fluorescence and phosphorescence of OLED devices. Four groups of OLED devices were prepared by adding yellow light emitting phosphor, yellow light phosphor and red light emitting phosphor and red light phosphor to czphoni material. The electroluminescent properties of these devices were studied in detail. We found that the external quantum efficiency of the fluorescent OLED devices and the phosphorescent OLED devices exceeded their corresponding theoretical values. It is found that efficient energy transfer between host and guest and the action of upconversion of three line exciton through TTA process to single line exciton play an important role in fluorescent OLED devices and phosphorescent OLED devices. At the same time, the luminescence process of the phosphorescent device also includes the direct capture of the carrier to form a exciton. In addition, the results also showed that the target dopant concentration of the optimized fluorescent OLED devices and phosphorescent OLED devices was high. It was verified that the tert butyl group connected with czphoni on the main material played an important role in improving the thermal stability of czphoni and inhibiting the quenching of the concentration of guest materials. 3. The properties and luminescence mechanism of the interface of heterostructure excimer and heterostructure non radical complex with rubrene ultrathin luminescent layer were investigated. The heterojunction structure induced non interface exciplex composite interface, heterojunction structure, and insert the ultra-thin yellow fluorescent light-emitting layer rubrene in the middle of the two interface, two OLED devices were prepared, and by optimizing the ultra-thin light emitting layer thickness, to obtain high performance yellow light OLED device. The radical complex is a charge transfer state between the receptor material and the donor material, so the radical complex has the ability to realize the TADF process. It is found that the energy transfer and upconversion of the three line exciton in the above OLED devices are the main mechanism of luminescence. In the OLED devices based on the excimer, the direct excitation of carriers is the main mechanism of luminescence. OLED device exciplex was obtained based on the maximum power efficiency, the maximum brightness 16.6cd/a 18311cd/m2 the maximum current efficiency of 12.7lm/w and OLED devices; non exciplex was obtained based on the high power efficiency, the maximum brightness 17.3cd/a 11860cd/m2 the maximum current efficiency and 8.1lm/w. 4. The composition of the yellow light and ultrathin layer structure of the doped layer structure is systematically studied.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TN383.1

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