【作者】 林慧；

【导师】 蒋亚东；

【作者基本信息】 电子科技大学 ， 光学工程， 2008， 博士

【摘要】 自从1986年美国柯达公司的邓青云博士等人首次成功制备有机双层异质结器件以来，有机光电器件由于具有广泛的应用前景受到科研院所和公司的广泛关注。有机小分子器件，如有机电致发光器件（Organic light-emitting diodes，OLEDs）、有机场效应管（Organic thin film transistor，OTFT）、有机光伏器件（Organic photovoltaic cells，OPVs）及有机激光器（Organic laser）都得到了研究。其中，可用作照明和信息显示的OLEDs也称有机电致发光器件，具有自发光、响应快、全固态、制备工艺简单、宽视角、超薄、耐高低温、柔性等优点，被誉为最理想和最有潜力的下一代显示技术。而有机光伏器件，与无机的器件相比，具有可大面积制备、可弯折、低成本等优点。但是，目前高的制造成本、有待于提高的器件效率、器件工作机理认识的不足，大大影响了有机光电器件的产业化进程。针对上述问题，本论文在刚性和柔性OLEDs的制备工艺和高效有机光伏器件方面进行了一系列的探索性的工作，具体包括：1．采用直流加水磁控溅射法，制备了具有良好导电性和高透过率的氧化铟锡（ITO）薄膜。通过L₁₈（3⁵）的正交实验，系统性地研究了材料工艺参数（水分压、工作气压、基片温度、氧气流量和溅射功率等）对ITO薄膜光电性能的影响。采用了方阻标定、透过率、AFM（Atomic force microscopy）、XRD（X-ray diffraction）等方法对ITO进行了测试和表征，并获得了优化的工艺参数。按优化工艺参数制备出的ITO导电基板在可见光区域的平均透过率为83％，方阻达到53Ω／□。采用该方法制备的ITO薄膜制备了结构为Mg：Ag／Alq（40 nm）／NPB（15 nm）／CuPc（x nm）／ITO（100 nm）的倒置型OLED器件，并对CuPc的厚度进行了优化。当CuPc厚度为15 nm时，驱动电压为14 V下发光亮度达到了526 cd／m²。2．在低温条件下，采用加水直流磁控溅射法制备了基于柔性衬底的ITO导电薄膜。详细地研究了衬底温度、溅射功率和溅射压强等工艺参数对柔性衬底上ITO薄膜光电性能的影响。在导电薄膜厚度为100 nm条件下，获得的最佳工艺参数如下：衬底温度50℃、溅射功率100 W和溅射压强2 mTorr。为了解决导电薄膜附着性差的问题，在柔性基板和ITO导电薄膜间加入一层紫外固化胶作为改性层。制备了结构为PET／buffer layer／ITO／NPB／Alq／Mg：Ag的柔性有机电致发光器件，器件在12 V电压下亮度达到了3286 cd／m²。3．对透明阴极结构及制备工艺进行了研究，在此基础上，制备了有机电致发光器件。根据矩阵光学理论，采用Matlab编程的方法计算了光学匹配层的参数。制备了结构为ITO／CuPc（20 nm）／NPB（30 nm）／Alq（40 nm）／LiF（1 nm）／Al（1 nm）／Ag（24 nm）／Alq（50 nm）的透明有机电致发光器件。结果表明，当驱动电压为15V时，器件亮度达到了4536 cd／cm²。4．研究了CuPc、C₆₀厚度对单异质结有机太阳能电池性能的影响。选用BCP、Alq、CuPc作为激子阻挡层制备了结构为ITO／CuPc／C₆₀／EBL／Ag双异质结OPV器件，从原理上分析了激子阻挡层在提高器件性能上发挥的作用。5．将磷光材料bis[2-（4-tertbutylphenyl）benzothi azolato-N，C2，]iridiumm（acetylacetonate）[（t-bt）₂Ir（acac）]加入有机光伏器件，用于提高器件的转换效率。制备了结构为ITO／CuPc：x％（t-bt）₂Ir（acac）／C₆₀／BCP／Ag、ITO／（t-bt）₂Ir（acac）／CuPc／C₆₀／BCP／Ag和ITO／CuPc／（t-bt）₂Ir（acac）／C₆₀／BCP／Ag的OPV器件，分析了三线态材料对于提高OPV效率所起到的作用。综上所述，本工作通过ITO透明基板的制作，尤其是柔性基板的制作，为柔性光电器件的进一步研究，打下了坚实的工艺和理论基础；同时，在有机太阳能电池领域，也进行了有益的探索，为高效器件的研制做了前期的铺垫。更多还原

【Abstract】 Since Tang et al at Eastmank Kodak firstly demonstrated an organic bilayerheterojunction （HJ） cell with high performance in 1986,organic optoelectronic deviceshave attracted great interest in academic and industrial field as a result of their highlypotential applications.So far,many organic small molecular devices have been studied,e.g.organic light-emitting diodes （OLEDs）,organic thin film transistor （OTFT）,organic photovoltaic （OPV） cell and organic laser.OLEDs as illumination source andbacklight for fiat panel display,possess many advantages,e.g.,self-emission,fastresponse,full solid device,easy fabrication,high efficiency,wide view-angle,ultrathinthickness.Therefore,OLEDs are considered as the most ideal and potential displaytechnology in 21^st century.Compared to inorganic PV cell,OPVs have beenrecognized for their potential use in large-area,flexible,and low cost photovoltaicapplications asa renewable energy source.However,currently there are also several shortcomings to prevent organicoptoelectronic devices from large scale commercial application such as highfabrication cost,low power efficiency and indistinct understanding about devicemechanism.Aiming at those problems,in this word,some basic and systematic workshave been performed to focus on the fabrication process to obtain high performancerigid and flexible OLED and high efficiency OPVs.The main works in this thesis areas following:1.ITO thin films with high optical transparency and electrical conductivity werefabricated by DC magnetron sputtering method with the assistance of tiny water vaporduring deposition process.The parameters of water partial pressure,total pressure,substrate temperature,oxygen flow rate and sputtering power were scrutinized withrespect to their role in the texturing process,and orthogonal test table L₁₈ （3⁵） wasdesigned to carried out the systematic study.Sheet resistance,transmittance,atomicforce microscope,and X-ray diffraction were employed to characterize the ITO films.The results showed that the transmission of 100 nm ITO conductive substrate wasaround 83% and square resistivity was below 53Ω/□.The film was used as the transparent anode to fabricate an inverted top-emitting organic light-emitting device（IT-OLED） with a structure of Mg:Ag/Alq （40 nm）/NPB （15 nm）/CuPc （x nm）/ITOanode （100 nm）,where the film thickness of CuPc was optimized.It was found that theluminance of IT-OLED with 15 nm of CuPc layer was 526 cd/m² at 14 V.2.ITO films were fabricated on flexible substrate using a DC magnetronsputtering process at low temperature with the introducing of tiny water vapor.Thecorrelation of deposition condition and ITO film properties was systematicallyinvestigated.The optimized parameters of sputtering ITO film with thickness of 100nm are as follows:substrate temperature 50℃,DC power 100 W,and depositionpressure 2 mTorr.To enhance the adhesion of ITO film on flexible substrate,aUV-curable resin was introduced as a buffer layer between polymeric plastic substrateand ITO film.Flexible OLED with a structure of PET/buffer layer/ITO/NPB/Alq/Mg:Ag was fabricated.A maximum luminance of 3286 cd/m² at 12 V was achieved.3.The structure and fabrication process of transparent cathode for transparentOLED were investigated.Computer aided design using Matlab based on matrix opticstheory was developed for the optimization of index match layer.The FOLED with astructure of ITO/CuPc （20 nm）/NPB （30 nm）/Alq （40 nm）/LiF （1 nm）/Al （1 nm）/Ag（24 nm）/Alq （50 nm） was fabricated.A maximum luminance of 4536 cd/m² at 15Vwas obtained.4.The influence of film thickness of CuPc and C₆₀ layer in single heterojunctionorganic solar cell was systematically investigated.Three different exciton blockingmaterials including BCP,Alq and CuPc were used in organic solar cell with a structureof ITO/CuPc/C₆₀/EBL/Ag.The influence of exciton blocking materials on deviceefficiency was discussed in detail.5.A novel phosphor of bis[2-（4-tertbutylphenyl） benzothi azolato-N,C2,]iridiumm （acetylacetonate） [（t-bt）₂Ir（acac）] was doped in CuPc as a donor to fabricate amore efficient organic solar cell.The device with a structure of ITO/CuPc:x%（t-bt）₂Ir（acac） /C₆₀/BCP/Ag,ITO/（t-bt）₂Ir（acac）/CuPc/C₆₀/BCP/Ag and ITO/CuPc/（t-bt）₂Ir（acac）/C₆₀/BCP/Ag were fabricated.The function of triplet materials on deviceefficiency was explained in theory.In summary,this work paves the way for high-efficiency flexible optoelectronicdevice based on the fabrication of rigid substrate as well as flexible substrate,and some effective preliminary works have been carried out on high performance organicsolar cell.We are optimistic that flexible organic solar cell with high efficiency can beachieved using our flexible substrate in the very near future.更多还原