Ir(ppy)3掺杂PVK体系发光特性的研究  

Luminescence Characteristics of PVK Doped with Ir(ppy)_3

作　　者：杨少鹏[1] 张雪峰[1] 赵谡玲[2] 徐征[2] 张福俊[2] 杨雅茹[1] 李庆[1] 庞学霞[1] 

机构地区：[1]河北大学物理科学与技术学院,河北保定071002 [2]北京交通大学光电子技术研究所,发光与光信息技术教育部重点实验室,北京100044

出　　处：《光谱学与光谱分析》2008年第3期512-516,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(60678006);河北省科技领军人才创新基金项目(06547002D-4);河北省自然科学基金项目(E2007000196)资助

摘　　要：对常温下磷光染料Ir(ppy)3掺杂PVK薄膜的光致发光(PL)和电致发光(EL)特性进行了研究。器件结构为ITO/PEDOT:PSS/PVK:Ir(ppy)3/BCP/Alq3/Al。实验发现随磷光材料掺杂浓度的不同,器件的发光性能发生变化。当浓度适宜时,主体材料PVK的发光很弱,主要为Ir(ppy)3的磷光发射。通过L-I-V特性曲线的比较,掺杂浓度为5%的光电性能最好,说明器件在掺杂浓度为5%时效果最佳。With the increasing development of organic light emitting devices（OLED）,interest in the mechanisms of charge carrier photogeneration,separation,transport and recombination continues to grow.Electromodulation of photoluminescence has been used as an efficient probe to investigate the evolution of primary excitation in all electric field.This method can provide useful information on carrier photogeneration,the formation and dissociation of excitons,energy transfer,and exciton recombination in the presence of electric field.The operation of OLED brings electrons and holes from opposite electrodes and generates singlet and triplet excitons.However,triplet excitons are wasted because a radiative transition from triplets is spin-forbidden.Spin statistics predicts that singlet-to-triplet ratio is 1：3 in organic semiconductors.One way to harvest light from triplet excitons is to use phosphorescent materials.These materials incorporate a heavy metal atom to mix singlet and triplet states by the strong spin-orbit coupling.As a result,a spin forbidden transition may occur allowing an enhanced triplet emission.Among phosphorescent materials,Ir（ppy）3 has attracted much attention because of its short triplet lifetime to minimize the triplet-triplet annihilation.High quantum efficiencies have been obtained by doping organic molecules and in polymers with Ir（ppy）3.In the present paper,the photoluminescence and electroluminescence spectra of Ir（ppy）3 doped PVK film are measured at room temperature.The device structure is ITO/PEDOT：PSS/PVK：Ir（ppy）3/BCP/Alq3/Al.The results show that the luminescence capabilities of devices are different when the concentration of Ir（ppy）3 is different.When the concentration of Ir（ppy）3 is suitable,the luminescence of PVK is lower but that of Ir（ppy）3 is stronger relatively,indicating that the energy transfer from the host materials to the guest materials is sufficient.It is concluded that the device with 5% of Ir（ppy）3 has the best luminescence properties ac

关 键 词：电致发光 磷光 能量传递 

分 类 号：TN383.1[电子电信—物理电子学]