| 题名 | 有机半导体材料的激光性能研究 |
| 作者 | 张镭 |
| 学位类别 | 博士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院大学 |
| 导师 | 刘星元 |
| 关键词 | BODIPY 放大自发辐射 稳定性 有机发光二极管 光学微腔 |
| 其他题名 | Study on Laser Performance of Organic Semiconductor Material |
| 学位专业 | 凝聚态物理 |
| 中文摘要 | 有机半导体材料一般都具有共轭结构，可以根据功能需要进行分子结构设计，因此具有种类丰富，结构多样的特点。其发射光谱可覆盖整个可见光谱区，激子的热稳定性能非常好，是激光增益材料的一个重要分支。以有机半导体材料作为增益介质的光泵浦和电泵浦激光器，是有机光电子领域之中的研究热点之一。有机材料可以通过多种低成本的方法成膜，易形成无定形薄膜，对衬底要求较低，在刚性或者柔性衬底上都可以沉积。但是，有机材料的分子间作用力较弱，材料的稳定性较差，其性能很容易受到周围环境的温度以及空气中氧气和水汽的影响而劣化。因此，有机光电子器件在实用化之前都必须解决封装问题，以防止材料的老化。有机半导体激光已有多年的研究历史，但是大部分材料的激光阈值偏高，不利于电泵浦激光的实现，而且激光性能的稳定性方面的研究报道偏少。因此，研究开发新型的有机激光材料，实现低阈值且性能稳定的光泵浦激光是有机激光技术发展的重要基础工作。本文以此为目标，开展了如下的研究工作。 一．氟硼二吡咯类材料的放大自发发射（ASE）性能研究 以氟硼二吡咯（BODIPY）为母体的各种衍生物类荧光染料，具有较高的荧光量子产率和光稳定性。在其基本的分子结构中引入不同的分子基团，可使其发光性质得到功能化的调节。我们对苯基，萘基和蒽基取代的三种BODIPY衍生物材料PhBOD，NaBOD和EnBOD的受激发射性能进行了研究。发现它们在甲苯中都具有良好的ASE性能，ASE效率均超过了22%。其中，浓度为0.008 Mol·L-1的PhBOD甲苯溶液样品的ASE阈值约99 kW·cm-2，该样品的光 稳定性非常高，在同一位置经紫外脉冲激光的20万次泵浦，ASE的强度衰减为初始强度的80%以上。将三种材料掺杂进PS中制备成薄膜，在大气环境中放置三个月后，PhBOD，NaBOD和EnBOD样品的ASE阈值分别是初始时的2.99倍，2.85倍和3.76倍。在高温100℃的条件下进行测试，PhBOD，NaBOD和EnBOD样品的ASE阈值是在室温状态时的1.88倍，4.94倍和5.41倍。 二．F-NI，TR-NI和PY-NI三种材料的ASE性能研究 这三种材料是带有萘单酰亚胺基团的芴、三聚茚和芘的衍生物材料。研究结果表明，它们不但具有良好的ASE性能，而且热稳定性能和环境中的放置稳定性非常好。其中，PS:F-NI薄膜在高温200℃的环境条件下进行测试，仍然能保持较低的ASE阈值，其阈值是室温下的1.17倍，而且光谱峰位没有偏移。样品在大气气氛中放置一年，ASE阈值几乎没有变化。 三. 新型的电子注入层材料YF3 电子传输材料和电子注入材料在OLED中比较缺乏。我们利用氟化钇(YF3)代替LiF作为电子注入层材料，制备了结构为Glass/ITO/NPB/Alq3/YF3 /Al有机电致发光器件（OLED）。结果表明：适当厚度的YF3 电子注入缓冲层可以增强阴极的电子注入能力，使得电子和空穴的浓度更加平衡，有效地提高器件的电致发光性能。其中，1.2 nm厚YF3的器件具有最小的起亮电压2.6 V，最高的电流效率8.52 cd·A-1，最大的亮度36530 cd·m-2。最大亮度和电流效率与LiF参考样品相比，分别提高了39%和53%。 四．650 nm的光泵浦有机微腔激光 我们设计研制了以分布式布拉格反射镜（DBR）为腔镜，以主客体掺杂的红光发光材料Alq3:DCJTI为增益介质的有机微腔结构。在紫外脉冲激光的泵浦下获得了波长650 nm的激光，其阈值强度约为110 W·cm-2，阈值前后FWHM从4.7 nm窄化到3.2 nm。 |
| 英文摘要 | Generally, organic semiconductor materials have a conjugate structure, their molecular structure can be designed to meet the need of function. Their emission spectra can cover the entire visible spectrum region. Organic excitons show a very good thermal stability. Organic materials have the characteristic of diversity of structure and abundant species, and are an important branch of the laser gain materials. Optically and electrically pumped lasers based on organic gain medium is one of the hot spot in the field of organic optoelectronics. Organic materials can form amorphous thin films through a variety of low-cost ways. They have low requirement to the substrate, and can be deposited on both rigid or flexible substrates. However, organic materials have weak molecular interaction forces, show bad stability. The material performance is very vulnerable to the temperature of the surrounding environment and the influence of oxygen and water vapor in the air. Therefore, encapsulation problems must be solved before practical application of organic optoelectronic devices, in order to prevent the material degradation. Organic semiconductor laser has many years of research history, but most of the materials have a high laser threshold, which is not conducive to the realization of the electrically pumped organic laser, and the study on stability of the laser performance is seldom reported. Therefore, the research and development of new organic laser materials, and the realization of low threshold and stable optically pumped organic lasers are the important basis for the development of organic laser technology. In this thesis, we carried out the following research work for the target. 1. Amplified spontaneous emission (ASE) properties of BODIPY derivatives As fluorescent dyes, BODIPY derivatives have high fluorescent efficiency and light stability. Their luminescent properties can be modified by the introduction of different molecular groups in their basic molecular structure. We studied the stimulated emission properties of phenyl, naphthyl and anthracene substituted BODIPY derivatives (PhBOD, NaBOD, and EnBOD). We found that they have good ASE performance in toluene, their ASE efficiency are more than 22%. Among them, the ASE threshold is about 99 kW·cm-2 at the concentration of 0.008 Mol·L-1 for the PhBOD toluene sample. The ASE intensity remains 80% of the initial value after 200000 pump pulses in the same position, which implies a very high photostability of the PhBOD material. Films of the three materials can be prepared by doping them into PS. When placed in the atmospheric environment after three months, the ASE thresholds of the PhBOD, NaBOD and EnBOD samples increased 2.99, 2.85, and 3.76 times, respectively. Under the test condition of high temperature 100 ℃, the ASE thresholds of PhBOD, NaBOD and EnBOD samples were increased 1.88, 4.94, and 5.41 times in comparison with the case of room temperature. 2. The ASE properties of F-NI，TR-NI, and PY-NI materials These three kinds of materials are fluorene, three indene and pyrene derivatives with naphthalene imide group. The results show that they have not only good ASE performance, but also good thermal and environmental stability. Among them, the PS: F-NI thin film were tested under the condition of 200 ℃ high temperature environment, the sample can still maintain a lower ASE threshold, and ASE peak position shows no deviation. the threshold value is higher than the value at room temperature only 1.17 times. ASE threshold was nearly unchanged after the sample waw placed in air atmosphere for a year. 3. New electronic injection layer material YF3 Organic light emitting devices (OLEDs) were fabricated with yttrium fluoride (YF3), instead of lithium fluoride (LiF), as electron injection layer. The experimental results showed that YF3 injection buffer layer with appropriate thickness can effectively enhance the electron injection ability of the cathode, leading to more balanced concentration of electrons and holes, and optimized electroluminescent properties of OLEDs. The OLED with 1.2 nm-thick YF3 layer had the minimum turn-on voltage of 2.6 V, the maximum current efficiency of 8.52 cd·A-1, and the maximum luminance of 36530 cd·m-2. Compared with LiF reference sample, the maximum brightness and current efficiency were increased by 39% and 53%, respectively. 4. Optically pumped organic microcavity lasers at 650 nm Organic microcavity structures were designed and fabricated with distributed Bragg reflector as the mirror, and Alq3:DCJTI host-guest doping system as the gain medium. The standing wave field within microcavity was simulated by using the transfer matrix method, and a suitable microcavity structure was determined. The lasing properties of the microcavity laser were studied by a UV pulse laser. The output wavelength of the microcavity laser is 650 nm. An obvious lasing behavior was observed with a threshold intensity of 110 W·cm-2. The FWHM was narrowed from 4.7 to 3.2 nm before and after the threshold. |
| 公开日期 | 2015-12-24 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ciomp.ac.cn/handle/181722/48948]  |
| 专题 | 长春光学精密机械与物理研究所_中科院长春光机所知识产出 |
| 推荐引用方式 GB/T 7714 | 张镭. 有机半导体材料的激光性能研究[D]. 中国科学院大学. 2015. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论