【作者】 钟建；

【导师】 蒋亚东；

【作者基本信息】 电子科技大学 ， 光学工程， 2011， 博士

【摘要】 在现今的平板显示器和新能源领域,柔性光电子器件以其显著的特点得到众多公司、科研院所和高校的广泛重视和深入研究,作为光电转换互逆的两个过程的器件,主要以柔性有机电致发光器件（flexible organic light-emitting devices, FOLED）和柔性有机薄膜光伏器件（organic thin-film photovoltaic devices, FOPVD）为代表。柔性OLED,在信息显示技术领域上属于新崛起的器件种类,被誉为“梦幻显示器”、“第三代显示技术”,而FOPVD作为新能源器件的一种,因其制备技术先进、性能优越、成本低廉、用途广泛而备受关注。但是,有待提高的器件效率、稳定性的不足、阵列化制备工艺的复杂性、原材料缺乏及产业链的不够完善,大大影响了柔性有机光电器件的研发进程。针对上述问题,本论文在柔性OLED的光电性能改善、阵列化技术、制备工艺和FOPVD效率等方面进行了一系列的探索性和创新性的研究工作,具体包括:1.采用在柔性PEN塑料基底和ITO导电薄膜之间引入致密缓冲层的方法,改善基底的致密性和平整性,进而提高基底与导电薄膜间的贴附性。采用低温直流磁控溅射技术,在制备有缓冲层的PEN塑料基底上溅射透明导电ITO薄膜,完成FOLED的阳极工艺制备。在基底温度为70℃、溅射功率为200 W、靶基距离为40 cm、溅射气压为1 mTorr、水分压为2×10^-5 Torr条件下,得到透明ITO导电薄膜的方块电阻为29.2Ω/sq,透过率为85.1 %。2.研究了基于单色FOLED原理性器件的结构、功能层、激子发光、客体掺杂机理和光电性能。分别制备了R、G、B单色FOLED器件样品,其中绿色FOLED器件,最高亮度为16900 cd/m²,在工作电压3.3 V时,最大功率效率为7.59 lm/W,从无磷光材料掺杂到掺杂浓度为4 %时,亮度增加了45.7 %,发光效率提高了50.2 %,功率效率提高了109.6 %;红色FOLED在测试时,最高亮度为8400 cd/m²,在工作电压3.9 V时,最大功率效率为3.02 lm/W,发光效率最大值为3.75 cd/A。器件发光的色坐标由橙红色向红色漂移,当掺杂浓度为10%时,器件的CIE为x=0.66,y=0.33,发光区域处于纯正红光区;蓝色FOLED在测试时,最高亮度为7500 cd/m²,在工作电压3.5 V时,最大功率效率为:1.87 lm/W,发光效率最大值为:2.09 cd/A,器件从零掺杂到掺杂浓度为6 %时,亮度增加的了23.2 %,发光效率提高了60.7 %,功率效率提高了70.1 %。3.研究了4英寸三基色FOLED阵列化的相关技术,讨论了FOLED显示屏的彩色化方案、详细论述了显示屏的阵列化设计方案与制备工艺、器件的结构设计与制备工艺、评价参数与测试等。论文阐述了柔性基底的清洗工艺、预处理技术、器件光掩膜的设计、机械掩膜设计、NiCr层图案设计、ITO层图案设计、绝缘层图案设计、阴极隔离柱设计与制备、有机材料功能层真空热蒸镀技术、金属阴极的蒸镀技术、薄膜封装技术等相关工艺,完成了4英寸三基色FOLED显示屏整体设计、工艺方案和样品制备,提出了柔性显示屏的技术参数评价体系并进行相关参数的测试。4.基于聚合物材料P3HT研究FOPVD的光电性能,一方面将金属氧化物MoO3应用到双异质结FOPVD器件中,另一方面在体异质结器件引入缓冲层,结构为:ITO/PEDOT:PSS/P3HT:PCBM/Bphen/Ag的体异质结器件,转换效率达到3.30 %,比没有缓冲层结构的器件提高了两个数量级;针对单异质结柔性有机薄膜光伏器件开路电压较低的问题,其一是设计具有中间层的中间异质结器件,其二是使用高开路电压材料SubPc为供电子体,以提高柔性光伏器件的开路电压,结构为ITO/SubPc （20 nm）/C60 （40 nm）/BPhen （10 nm）/Ag （130 nm）的器件的开路电压达到0.87 V,在制备的一系列器件中为最佳。5.利用混合薄膜叠层方法对柔性器件进行薄膜封装,在初始亮度为10000 cd/m²的,电压9 V时,完成器件加速寿命测试,经测试五种薄膜封装结构的数值分别为:897小时、1495小时、2093小时、2830小时和2890小时。单层的有机薄膜（单体）1与单层的无机薄膜（Al₂O₃）₁的封装效果比较,柔性器件的半衰寿命提高了66.7 %;与（单体+Al₂O₃）₁与（单体）1的封装效果比较,寿命提高了39.8 %; （单体+Al₂O₃）₂与（单体+Al₂O₃）₁的封装效果比较,寿命进一步提高,改善了35.1 %; （单体+Al₂O₃）₃与（单体+Al₂O₃）₂的封装效果比较,寿命基本一致,仅提高了2.1 %。综上所述,本论文的工作将主要集中在柔性基底的选取与缓冲层引入的影响、基于柔性塑料基底的R、G、B三基色OLED原理性器件的光电性能参数优化、柔性4英寸OLED器件的阵列化技术研究、样品的制备;同时,对FOPVD光电性能研究及薄膜封装技术也进行了有益的探索,为高性能柔性光电器件的研制和应用打下了基础。更多还原

【Abstract】 In the field of flat panel displays and renewable energy, flexible optoelectronic devices with their remarkable features drew lots of attention, and as the reciprocal of two photoelectric conversion process devices, mainly in flexible organic light-emitting devices （FOLED） and flexible organic thin-film photovoltaic devices （FOPVD） were focused on. Flexible OLED is an emerging device type in the field of display technologies, known as the“Dream Displays”,“Third-generation Display Technologies”.Alsoe, FOPVD as the representative of new energy devices, because of its advanced preparation technologies, superior performance, low cost and widely use , is drawing a large volume of interest.Currently, however, the improvement of efficiency, the insufficient of stability, the complex preparation of the array process, high cost, greatly affect the industrialization process of flexible organic optoelectronic devices. In response to these problems as well as aiming at the performance improvement of flexible paasive matrix OLED （PMOLED）, array technologies and efficiency of FOPVD, a series of basic and applied basic research work was carried out, which includes:1. By introducing buffer layer between flexible plastic substrate PEN and conductive ITO film, the water and oxygen resisitance and smoothness of flexible substrate were improved, thereby the adhesion between substrate the conductive film was enhanced. Using low temperature DC magnetron sputtering method, sputtering transparent conductive ITO film on a buffer layer, which has been prepared on PEN plastic substrate, was fabricated as the anode of FOLED. With a substrate temperature of 70 oC, a sputtering power of 200 W, a distance of target base of 40 cm, a sputtering pressure of 1 mTorr, a water pressure of 2×10^-5 Torr, a transparent ITO substrate with a sheet resistance of 29.2 /sq and a transmittance of 85.1 % was obtained.2. Research on the architecture, the functional layer material, exciton luminance and the doping mechanism of host-guest of flexible OLED devices was performed. Three kinds of samples of monochrome flexible passive matrix OLED （PMOLED） of red, green, blue color were studied. As for green FOLED, a maximum brightness is 16900 cd/m², and a maximum power efficiency can be 7.59 lm/W at 3.3 V were obtained, when the doping concentration phosphorescent material changes from 0 % to 4 %. This indicated that the brightness increased by 45.7 %, luminous efficiency power efficiency were improved by 50.2 % and 109.6 %, respectively. In the case of red FOLED, a maximum brightness of 8400 cd/m², amaximum power efficiency of 3.02 lm /W at 3.9 V, and amaximum luminous efficiency of 3.75 cd/A was obtained. The FOLED color coordinates shift from orange-red to red. When the doping concentration is 10 %, the Commission Internationale De L E’clariage （CIE） coordinates are （0.66, 0.33）, and pure red light was achieved. As for blue FOLED, a maximum brightness of 7500 cd/m², a maximum power efficiency can be 1.87 lm/W at 3.5 V, and a maximum luminous efficiency of 2.09 cd/A were obtained. When the doping concentration changes from very low to 6 %, the brightness increased by 23.2 % luminous efficiency and power efficiencwere improved by 60.7 % and 70.1 %, respectively.3. After the array technology of flexible 4-inch trichromatic PMOLED was studied, the colorization process of flexible PM-OLED was discussed. Especially, the array design scheme of FOLED display screen and preparation technologies were proposed, which covers device design and laboratory preparation, technical parameters and testing. When the flexible substrate cleaning process, pre-processing technology, photomask design, mechanical mask design, NiCr layer design, ITO layer designs, insulation graphic design, column design, the fabrication of cathode isolation, the vacuum deposition technologies of functional organic materials layer, the deposition technologies of the cathode metal, thin-film encapsulation and other related processes were described, a 4-inch trichromatic flexible PMOLED display was completed including design, programs and sample preparation process, and device parameter evaluation and testing system.4. Based on a polymer material of P3HT, the performance of FOPVDs was investigated. On one hand, the metal oxide MoO3 to a bilayer heterojunction （HJ） device was applied. On the other hand, a buffer layer into body heterojunction devices with structure of ITO/PEDOT: PSS/P3HT: PCBM/Bphen/Ag was introduced. The result showed that a conversion efficiency of 3.30 %, which increased by two orders of magnitude compared to the devices without buffer layer, was obtained. To solve the problem of the low open voltage of single-heterojunction FOPVD, Firstly, the heterojunction device with a middle layer heterojunction was design. Then, an electron donor material SubPc with a high open circuit voltage to improve the open-circuit voltage of the flexible photovoltaic devices was used, whose structure is ITO/SubPc （20 nm）/C60 （40 nm）/BPhen （10 nm）/Ag （130 nm）. A maximum open circuit voltage of 0.87 V for FOPVD was achieved.5. A stack method of mixed thin film to apply thin-film encapsulation to flexible devices was used, and the accelerated life of the FOLED was tested. When the initial luminance was 10000 cd/m², and the applied voltage is 9 V. The lifetime of the tested of five kinds of thin-film encapsulation devices were: 897, 1495, 2093, 2830, and 2890 hrs. Compared the effect of package of the single-layer organic thin film （Monomer）1 with the single-layer inorganic film （Al₂O₃）₁, the half-lifetime of flexible devices increased by 66.7 %. Compared the package of （Monomer+Al₂O₃）₁ with （Monomer）1, life improved by 39.8 %. Compared the package of （Monomer+Al₂O₃）₂ with （Monomer+Al₂O₃）₁, it improve by 35.1 %. Compared the effect of package of （Monomer+Al₂O₃）₃ with （Monomer+Al₂O₃）₂, life time is almost the same, only increased by 2.1 %.In summary, in this thesis the effect of the selection of flexible substrate, the introduction of buffer layer, optimization of optical performance parameters of R, G, B trichromatic light-emitting flexible components, which is based on flexible plastic substrate, array technologies of flexible 4 inches PM-OLED devices, and the preparation of samples, were focus on. Meanwhile, the exploration of of FOPVDs and the properties of thin-film encapsulation technologies, paved a solid way for the development and application of efficient flexible optoelectronic devices.更多还原