Author Affiliations
Abstract
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen, 518060, China
Two promising post-treatment techniques, i.e. applying tensile strain and rising temperature, are demonstrated to enhance the mode-coupling efficiency of the CO2-laser-induced long period fiber gratings (LPFGs) with periodic grooves. Such two post-treatment techniques can be used to enhance the resonant attenuation of the grating to achieve a LPFG-based filter with an extremely large attenuation and to tailor the transmission spectrum of the CO2-laser-induced LPFG after grating fabrication.
Long period fiber gratings Long period fiber gratings fiber Bragg gratings fiber Bragg gratings optical fiber sensor optical fiber sensor temperature temperature tensile strain tensile strain optical fiber device optical fiber device Photonic Sensors
2015, 5(4): 339
1 中山大学 光电材料与技术国家重点实验室,广东 广州 510275
2 深圳大学 光电子器件与系统(教育部、广东省)重点实验室,广东 深圳 518060
将厚度为0.5 nm的LiF薄层引入到双层有机电致发光器件(OLEDs)的Alq3发光/电子传输层中作为空穴阻挡/激子限制层,研究其位置对器件光电性能的影响。发现LiF薄层在不同位置均明显提高器件的发光效率,当LiF薄膜距离TPD/Alq3界面20-40 nm时,OLEDs的最大发光效率约为4.5 cd/A,是对比器件(没有LiF薄层)的1.8倍。OLEDs的电流密度随着减小LiF薄层与阴极的距离而增大。研究表明,这是因为LiF薄层可有效阻挡进入复合发光区域未复合的过剩空穴并导致其积累,空穴积累可提高电子传输区域中的电场,提高其中电子的传输和从阴极的注入,从而提高复合发光区域中的载流子平衡及其复合几率;LiF薄层可将激子限制在复合发光区域,减少激子被阴极淬灭的几率。
光学器件 有机电致发光器件 空穴阻挡/激子限制层 发光效率
