磁性电极作为衬底的有机电致发光器件

有机电致发光器件(Organic Light-Emitting Device, OLED)已成为当今最热门的研究领域之一。以钛酸锶(100)作为基底, 采用RF磁控溅射镀膜系统制成磁性电极La1-xSrxMnO3(LSMO)薄膜, 为了增加钛酸锶基底LSMO薄膜的透光率, 对该基底进行了双面光学抛光。在此基础上, 以LSMO为衬底, 制作了结构为LSMO/NPB/Alq3/CsF/Mg:Ag的有机电致发光器件。器件大约在14 V时启亮, 在25 V时, 器件达到最大亮度。在磁场作用下, 研究了器件的亮度-电压-电流特性。在大约150 mT磁场下, 器件的发光亮度增大10%。研究结果表明: 由于经LSMO注入发光层内部的电子和空穴自旋方向被部分极化, 发光层单线态与三线态激子的形成比率增加。由于发光材料Alq3是单线态有机材料, 因而, 器件发光亮度增大。

Organic light-emitting device based on LSMO

Organic Light Emitting Device(OLED) has been a promising new research area that has received a lot of attention in the recent. In this paper,the OLED was fabricated using spin LSMO substrate. The electrode was made of La1-xSrxMnO3(LSMO) thin films by RF magnetron sputtering with SrTiO3 (100) substrate. In order to increase light transmittance ratio of LSMO film, the substrate was double-sided polished. The structure was LSMO/NPB/Alq3/CsF/Mg:Ag. Light was emitted at above 14 V. The brightness of device was the most at 25 V. The characteristic brightness, voltage and current of these devices were investigated with the magnetic field. The brightness of device was improved 10% with 150 mT. The photovoltaic character was little affected by the magnetic field in the device using LSMO substrate. This phenomenon was related on the ratio of single exciton and triplet exciton in the emissive layer. it would then be possible to preferentially form triplets or singlets by controlling the spin polarizations of the injected carriers. As Alq3 belonged to singlet materials, the brightness of device was improved.