电场对OLED中自旋极化载流子输运的影响  

The influence of electrical field over transportation of spin-polarized carriers in OLED

作　　者：乔士柱[1] 赵俊卿[1] 贾振锋[1] 庞智勇[2] 

机构地区：[1]山东建筑大学理学院,山东济南250101 [2]山东大学物理学院,山东济南250100

出　　处：《山东建筑大学学报》2009年第5期402-406,共5页Journal of Shandong Jianzhu University

基　　金：国家自然科学基金项目(60676041);山东省自然科学基金项目(Y2006A18);山东建筑大学校内基金重点项目(XZ050102)

摘　　要：为了明确有机电致发光器件(OLED)双极自旋注入中电场的影响,从漂移扩散方程和载流子浓度连续性方程出发,结合泊松方程得出了注入载流子运动的微分方程,计算了自旋极化载流子浓度和自旋扩散长度的关系,讨论了电场对自旋扩散长度的影响。计算结果表明:电场通过改变自旋扩散长度来影响自旋极化载流子的运动。对电子来说,电场方向和扩散方向相同时,电场增大会导致自旋扩散长度减小,扩散变快,电子深入样品的平均距离小,不利于在有限厚度薄膜中获得高自旋极化率;电场方向和扩散方向相反时,电场越大,自旋扩散长度越大,有利于获得高自旋极化率。对空穴来说,情况正好相反。还讨论了电场对双极自旋极化注入的影响。In clarifying the effect of electrical field on double-electrode spin-injection in organic light- emitting device （ OLED）, in light of drift-diffusion equation and generalized continuity equation, obtained is differential equation with poisson equation. The study finds out the relationship between the density of spin-polarized carriers and spin diffusion length. The research also discusses the influence of electrical field on spin diffusion length. The study result shows that electrical field affects movement of spin-polarized carriers by altering spin diffusion length. In terms of electrons, if direction of electri- cal field is the same with that of diffusion, increasing of electrical field will lead to decreasing of diffusion length, which means accelerating of diffusion, and as a result, the average distance which electrons can reach in samples will be shorter, thus making it difficult to achieve high spin polarization in thin film. If direction of electrical field is reverse to that of diffusion, then, the stronger the electrical field is, the longer the diffusion length will be. So it will be easier to reach high spin polarization. There is a contrary result for electrons when it comes to holes. The paper also discusses the influence of electrical field over double-electrode spin injection, the result of which is significant to the researching and developing of spin-polarized electrode OLED and spin valve.

关 键 词：OLED 自旋注入 电场 自旋扩散长度 

分 类 号：TN383.1[电子电信—物理电子学]