本文選題：有機(jī)發(fā)光二極管 + 頂發(fā)射�。� 參考：《南京郵電大學(xué)》2015年博士論文

【摘要】：頂發(fā)射有機(jī)發(fā)光二極管(Top-emitting organic light-emitting diode,TEOLED),以其分辨率高、開口率大和襯底選擇靈活等優(yōu)勢在有機(jī)平板顯示領(lǐng)域,尤其是微顯示領(lǐng)域受到廣泛關(guān)注。然而,TEOLED中的光學(xué)微腔效應(yīng)嚴(yán)重抑制了器件的發(fā)光強(qiáng)度和色純度,其對(duì)藍(lán)色和白色TEOLED的影響尤其嚴(yán)重,造成了藍(lán)、白光TEOLED制備困難,并嚴(yán)重影響了器件性能。因此,開展TEOLED中微腔效應(yīng)的研究工作,有效設(shè)計(jì)與調(diào)控微腔對(duì)于成功制備高性能藍(lán)、白光TEOLED至關(guān)重要。本文首先將電偶極子理論和傳輸矩陣?yán)碚撓嘟Y(jié)合改進(jìn)了微腔效應(yīng)的理論模型,并與實(shí)驗(yàn)相結(jié)合研究了微腔效應(yīng)對(duì)于藍(lán)光TEOLED的影響,設(shè)計(jì)了優(yōu)化的器件結(jié)構(gòu),有效增強(qiáng)了藍(lán)光強(qiáng)度并改善了藍(lán)光的色飽和度;在此基礎(chǔ)上,對(duì)白光TEOLED進(jìn)行了一系列的設(shè)計(jì)和優(yōu)化,提高了白光中藍(lán)光的比例,改善了頂發(fā)射白光的效率和色純度。研究工作主要包括以下幾個(gè)方面:(1)采用電偶極子輻射的經(jīng)典電磁理論分析激子的輻射模式,將偶極矩的取向和輻射電磁波的偏振等因素納入輻射模式的計(jì)算中,使理論模型更加完善。采用傳輸矩陣?yán)碚摲治龉獠ㄔ诙鄬幽は抵械膫鬏?將多膜層結(jié)構(gòu)的TEOLED等效為單層結(jié)構(gòu),結(jié)合偶極子輻射模式,研究TEOLED中微腔共振效應(yīng)對(duì)激子輻射的影響。運(yùn)用該理論模型,可以從理論上比較準(zhǔn)確地計(jì)算TEOLED的微腔共振光譜、發(fā)光光譜,并進(jìn)而計(jì)算色坐標(biāo)、色溫、顯色指數(shù)等器件的色度參數(shù)。(2)常規(guī)TEOLED中的微腔共振效應(yīng)抑制了藍(lán)光的出射,使藍(lán)光的效率和色度都比較差。為了改善藍(lán)光TEOLED的性能,本文引入了“金屬/Ag”雙層陰極結(jié)構(gòu),增強(qiáng)電子的注入效率和藍(lán)光耦合輸出效率。首先計(jì)算了金屬材料的折射率實(shí)部和虛部對(duì)雙層陰極反射率和反射相位的影響,確定“釤/Ag(Sm/Ag)”雙層陰極結(jié)構(gòu)能實(shí)現(xiàn)較低的反射。然后計(jì)算了不同Sm、Ag厚度對(duì)藍(lán)光TEOLED光譜和色坐標(biāo)的影響,發(fā)現(xiàn)減小Ag厚度,增加Sm厚度有利于改善藍(lán)光色純度。最后,制備了具有不同Sm/Ag雙層陰極的藍(lán)光TEOLED,驗(yàn)證了理論計(jì)算的結(jié)果,同時(shí)改善了頂發(fā)射藍(lán)光的色純度。最優(yōu)化藍(lán)光TEOLED的光譜接近藍(lán)光材料本征光譜,而且器件在0-75°視角范圍內(nèi)光譜幾乎沒有變化,實(shí)現(xiàn)了很好的色純度和角度穩(wěn)定性。(3)TEOLED中微腔效應(yīng)對(duì)藍(lán)光的抑制使頂發(fā)射白光中藍(lán)光的強(qiáng)度不夠,白光色度偏紅。本文利用微腔效應(yīng)中的多光束干涉增強(qiáng)藍(lán)光輸出強(qiáng)度,改善頂發(fā)射白光色度。首先,理論計(jì)算了具有不同空穴傳輸層(NPB)厚度TEOLED的微腔共振波長,并制備了相應(yīng)器件驗(yàn)證理論計(jì)算結(jié)果。理論和實(shí)驗(yàn)結(jié)果表明,當(dāng)NPB厚度為100 nm時(shí),微腔的共振波長與藍(lán)光比較匹配,器件中的藍(lán)光輸出較強(qiáng),能與紅光混合獲得比較平衡的白光。接著,通過在紅光和藍(lán)光層之間插入載流子/激子阻擋層,穩(wěn)定了主體材料CBP中的激子復(fù)合區(qū)域,使白光在不同電壓下的色漂移減弱,改善了白光的穩(wěn)定性。(4)微腔效應(yīng)中的干涉過程分為多光束干涉和寬角干涉。本文對(duì)白光TEOLED中的寬角干涉因子和多光束干涉因子分別進(jìn)行了計(jì)算和分析,以提高器件的效率和色度。首先計(jì)算了TEOLED中電極和激子位置對(duì)多光束干涉、寬角干涉強(qiáng)度的影響,發(fā)現(xiàn)增強(qiáng)陽極反射并減弱陰極反射可以減弱多光束干涉,而使發(fā)光激子靠近陽極可以增強(qiáng)寬角干涉,均能增強(qiáng)器件中的藍(lán)光輸出。接著,從實(shí)驗(yàn)上制備了高反射陽極和低反射陰極的白光TEOLED,并在此基礎(chǔ)上,利用δ摻雜器件和藍(lán)/紅、紅/藍(lán)結(jié)構(gòu)的白光TEOLED重點(diǎn)研究了寬角干涉對(duì)頂發(fā)射白光性能的影響,并利用寬角干涉進(jìn)一步增強(qiáng)藍(lán)光輸出。最終得到的白光TEOLED效率高于具有相同有機(jī)層結(jié)構(gòu)的底發(fā)射器件,同時(shí)色度更加接近標(biāo)準(zhǔn)白光。(5)在白光TEOLED中,引入異質(zhì)結(jié)結(jié)構(gòu)的雙藍(lán)光發(fā)光層,使激子復(fù)合區(qū)域位于藍(lán)光層內(nèi),有效提高了藍(lán)光的發(fā)光強(qiáng)度。為了優(yōu)化白光的色純度和穩(wěn)定性,對(duì)發(fā)光層中激子的行為進(jìn)行了研究。首先制備單載流子器件研究客體的載流子傳輸行為,發(fā)現(xiàn)藍(lán)光客體充當(dāng)空穴傳輸通道和電子陷阱,而紅光客體則充當(dāng)電子傳輸通道和空穴陷阱,其中紅光客體的陷阱效應(yīng)對(duì)低壓下的紅光強(qiáng)度有貢獻(xiàn);然后利用δ摻雜器件研究激子的分布,確定了激子在主體材料SPPO1中的擴(kuò)散長度,由此確定了藍(lán)光和紅光層的厚度;接著利用阻隔層研究了藍(lán)、紅客體之間的能量轉(zhuǎn)移,發(fā)現(xiàn)存在較弱的Dexter能量轉(zhuǎn)移,有助于提高白光的穩(wěn)定性。根據(jù)以上研究結(jié)果,設(shè)計(jì)了優(yōu)化的白光TEOLED結(jié)構(gòu),獲得了高效、穩(wěn)定的頂發(fā)射白光,效率為13.3cd/A,在10-104 cd/m2亮度范圍內(nèi),色坐標(biāo)漂移僅(0.009,0.001)。最后從激子擴(kuò)散、能量轉(zhuǎn)移和陷阱效應(yīng)等方面對(duì)器件的穩(wěn)定性機(jī)制進(jìn)行了深入的分析。
[Abstract]:The top emission organic light-emitting diode (Top-emitting organic light-emitting diode, TEOLED), with its high resolution, high opening rate and flexible substrate selection, has been widely concerned in the field of organic plate display, especially in the field of micro display. However, the optical microcavity effect in TEOLED seriously inhibits the light intensity and color purity of the device. The effect on blue and white TEOLED is especially serious, which causes the difficulty in the preparation of blue and white TEOLED, and seriously affects the performance of the device. Therefore, it is important to design and regulate the microcavity effect in TEOLED for the successful preparation of the high performance blue, the white light TEOLED to the gate. Combining with the theory, the theoretical model of microcavity effect is improved, and the effect of microcavity effect on blue light TEOLED is studied in combination with the experiment. The optimized device structure is designed, the blue light intensity is enhanced and the color saturation of blue light is improved. On this basis, a series of white light TEOLED is designed and optimized, and white light is improved. The proportion of blue light improves the efficiency and color purity of the top emitting white light. The research work mainly includes the following aspects: (1) the classical electromagnetic theory of electric dipole radiation is used to analyze the radiation pattern of the exciton, and the orientation of the dipole moment and the polarization of the radiation electromagnetic wave are incorporated into the calculation of the radiation mode, which makes the theoretical model more perfect. The transmission matrix theory is used to analyze the transmission of light wave in the multilayer film system, the TEOLED of the multi layer structure is equivalent to a single layer structure, and the effect of the resonance effect on the exciton radiation in TEOLED is studied by the dipole radiation mode. The theoretical model is used to calculate the microcavity resonance spectra and luminous light of TEOLED theoretically. The chromaticity parameters of the devices such as color coordinates, color temperature and color index are calculated. (2) the micro cavity resonance effect in conventional TEOLED inhibits the emission of blue light and makes the efficiency and chromaticity of blue light relatively poor. In order to improve the performance of blue light TEOLED, this paper introduces a "metal /Ag" double layer cathode structure to enhance the injection efficiency of the electron and Lan Guangou. The effect of the refractive index and the imaginary part of the metal material on the reflectivity and the reflection phase of the double cathode is calculated. The "SM /Ag (Sm/Ag)" double layer cathode structure can be determined to achieve a lower reflection. Then the effects of different Sm and Ag thickness on the blue light TEOLED spectrum and the color coordinates are calculated, and the thickness of Ag and the thickness of the Sm can be reduced. It is beneficial to improve the blue color purity. Finally, the blue light TEOLED with different Sm/Ag double layer cathodes is prepared. The result of the theoretical calculation is verified, and the color purity of the top emitting blue light is improved. The optimized blue light TEOLED spectrum is close to the intrinsic spectrum of the blue light material, and the device has almost no change in the spectrum within the range of 0-75 degrees. Good color purity and angle stability. (3) the inhibition of the microcavity effect on blue light in TEOLED makes the top emitting Bai Guangzhong blue light not strong enough and the white color is red. This paper uses the multi beam interference in the microcavity effect to enhance the blue light output intensity and improve the top emission white light chromaticity. First, the thickness of the different cavity transport layer (NPB) is calculated theoretically. The resonance wavelengths of the microcavity of TEOLED and the theoretical results of the corresponding device verification are prepared. The theoretical and experimental results show that when the thickness of NPB is 100 nm, the resonant wavelength of the microcavity is matched with the blue light, the blue light output in the device is stronger and the white light can be more balanced with the red light. Then, the load is inserted between the red and blue light layers. The flow sub / exciton barrier layer stabilizes the exciton complex region in the main material CBP, which reduces the color drift of the white light at different voltages and improves the stability of the white light. (4) the interference processes in the microcavity effect are divided into multi beam interference and wide angle interference. The wide-angle interference factors and multi beam interference factors in the white light TEOLED are respectively carried out in this paper. It is calculated and analyzed to improve the efficiency and chromaticity of the device. First, the influence of the electrode and exciton position in the TEOLED on the interference of multi beam and wide angle interference is calculated. It is found that the enhanced anode reflection and the weakening of the cathode reflection can weaken the multi beam interference, and the light exciton near the anode can enhance the wide angle interference, which can both enhance the device. The white light TEOLED with high reflection anode and low reflection cathode was prepared experimentally, and on this basis, the effect of wide angle interference on the white light performance of the top emission was studied with delta doping and blue / red, red / Blue structure of white light TEOLED, and the blue light output was further enhanced by wide angle interference. The final white light was obtained. The TEOLED efficiency is higher than that of the bottom emitting devices with the same organic structure, and the chromaticity is closer to the standard white light. (5) in the white light TEOLED, the double blue light layer of heterostructure is introduced to make the complex region of the exciton in the blue light layer, and the luminescence intensity of the blue light is improved effectively. In order to optimize the color purity and stability of white light, the luminescent layer is optimized. The behavior of the exciton is studied. First, single carrier device is prepared to study the carrier transport behavior of the object, and the blue object acts as the hole transmission channel and the electron trap, while the red object acts as the electron transport channel and the hole trap, in which the trap efficiency of the red light object contributes to the red light intensity under the low pressure; then the use of the red light object is used. The distribution of the exciton is studied by the delta doped device, the diffusion length of the exciton in the main material SPPO1 is determined, and the thickness of the blue and red light layers is determined. Then the energy transfer between blue and red objects is studied by the barrier layer, and the weak Dexter energy transfer is found to help to improve the stability of the white light. Based on the above results, The optimized white light TEOLED structure has been designed to obtain high efficiency, stable top emission white light, and the efficiency is 13.3cd/A. The color coordinate drift is only (0.009,0.001) in the 10-104 cd/m2 luminance range. Finally, the stability mechanism of the device is deeply analyzed from the exciton diffusion, the energy transfer and the trap effect.
【學(xué)位授予單位】：南京郵電大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN383.1

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本文編號(hào)：2094328