CAREER: Using Photonic Crystals to Control the Emission of Rare Earth-Doped Semiconducting Polymers

职业：利用光子晶体控制稀土掺杂半导体聚合物的发射

• 批准号: 0093502
• 负责人: Michael McGehee
• 金额: $ 37.5万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0093502&HistoricalAwards=false
• 关键词: CAREER; Using; Photonic; Crystals; Control

Light-emitting diodes (LEDs) made with semiconducting (conjugated) polymersnow have quantum efficiencies as high as 4 % and operating lifetimes of 50,000 hours.Several companies are developing flat panel displays with these LEDs. One of thelimitations of polymer LEDs is that triplet excitons are non-emissive. Initial stepstowards solving this problem by transferring energy to phosphorescent molecules andrare earth complexes have recently been taken. One of the goals of this project is tooptimize energy transfer and charge transport in "doped" polymer films so that highquantum efficiencies, low operating voltages and high device stability can be obtained.Another limitation of current polymer LEDs is that most of the emitted photons aretrapped in the device by total internal reflection and that the photons which do escapecannot conveniently be collimated into a beam or coupled into a waveguide. The secondmajor goal of the project is use photonic crystals, e.g. one-dimensional dielectric stacksand two-dimensional gratings, to control the directionality of emission. Previousattempts to do this have not been fully successful because it was not possible to makephotonic crystals with a photonic band gap wide enough to completely control theemission of conjugated polymers, which have an emission spectrum with a width of morethan 100 nm. By using rare earth-doped polymers, which have emission bandwidths ofless than 4 nm, it will be possible to use photonic crystals to control the directionality ofemission. This project will not only increase the efficiency and functionality of polymer-basedLEDs, but will also provide a convenient light source for developing the scienceand technology of photonic crystals.The project provides many excellent research opportunities for students. Theywill work with a team of chemists to design new rare earth complexes and learn thequantum mechanics that regulate energy transfer, charge transfer and light emission.They will interact with members of industry to learn how to optimize polymer LEDs.They will use computer modeling to design one-, two-, and three-dimensional photoniccrystals to control the emission of light. They will also get to interact with a team ofresearchers at 3M and have the opportunity to push polymer-photonic crystal science andtechnology into new directions. Most of the research will be done by two graduatestudents, but there will be many opportunities for undergraduates and M.S. students totake on short-term projects.New courses on nanotechnology and organic optoelectronics will be developed toprepare students for research. The course on nanotechnology is designed to makestudents in several departments aware of the opportunities in this exciting area and tofoster multidisciplinary research. The course on organic optoelectronics will have severallab sessions in the PI's labs so that students can reinforce what they learn in class. Highschool teachers will visit the labs during the summer and be trained to use a kit of opticalequipment so that they can demonstrate photonics experiments to their students.

由半导体（共轭）聚合物制成的发光二极管 (LED) 现在的量子效率高达 4%，工作寿命为 50,000 小时。多家公司正在开发采用这些 LED 的平板显示器。聚合物 LED 的局限性之一是三线态激子不发光。最近已经采取了初步措施，通过将能量转移到磷光分子和稀土配合物来解决这个问题。该项目的目标之一是优化“掺杂”聚合物薄膜中的能量转移和电荷传输，从而获得高量子效率、低工作电压和高器件稳定性。当前聚合物 LED 的另一个限制是大部分发射的光子被捕获在设备中通过全内反射，并且逃逸的光子不能方便地被准直成光束或耦合到波导中。该项目的第二个主要目标是使用光子晶体，例如一维电介质叠层和二维光栅，以控制发射的方向性。之前的尝试并未完全成功，因为不可能制造出具有足够宽的光子带隙的光子晶体来完全控制共轭聚合物的发射，而共轭聚合​​物的发射光谱宽度超过100 nm。通过使用发射带宽小于 4 nm 的稀土掺杂聚合物，将可以使用光子晶体来控制发射的方向性。该项目不仅将提高聚合物基LED的效率和功能，还将为光子晶体科学技术的发展提供便利的光源。该项目为学生提供了许多优秀的研究机会。他们将与化学家团队合作，设计新的稀土配合物，并学习调节能量转移、电荷转移和光发射的量子力学。他们将与行业成员互动，学习如何优化聚合物 LED。他们将使用计算机建模来设计一维、二维和三维光子晶体来控制光的发射。他们还将与 3M 的研究团队进行互动，并有机会将聚合物光子晶体科学和技术推向新的方向。大部分研究将由两名研究生完成，但本科生和硕士学位也会有很多机会。学生参加短期项目。将开发有关纳米技术和有机光电子学的新课程，为学生的研究做好准备。纳米技术课程旨在让多个系的学生意识到这个令人兴奋的领域的机会，并促进多学科研究。有机光电子学课程将在 PI 的实验室中举办几次实验课程，以便学生可以巩固在课堂上学到的知识。高中教师将在夏季参观实验室，并接受使用光学设备套件的培训，以便向学生演示光子学实验。