基于ZnS／SiO2量子点的EL器件及宽谱发射  

Broad emission from ZnS/SiO_2 quantum dots-based EL device

作　　者：罗程远[1] 张晓松[1] 徐建萍[1] 吴燕宇[1] 牛喜平[1] 李开祥[1] 葛林[1] 李岚[1] 

机构地区：[1]天津理工大学材料物理研究所显示材料与光电器件省部共建教育部重点实验室,天津300384

出　　处：《光电子．激光》2012年第9期1775-1779,共5页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(60877029,60977035,60907021,10904109);天津市自然科学基金(11JCYBJC00300,09JCYBJC01400);天津市高等学校科技发展基金(20071207);科技创新体系及条件平台建设计划项目“发光材料的制备与性能”(10SYSYJC28100);发光与光信息技术教育部重点实验室开放基金(2010LOI0,2010LOI11)资助项目

摘　　要：将ZnS/SiO2量子点与PVP在甲醇溶液中充分混合作为活性层材料,通过匀胶方法制备了ITO//ZnS/SiO2∶PVP//Al结构的电致发光(EL)薄膜器件。器件的EL光谱由510～560nm波段的绿光发射和相对较弱的蓝紫光(400nm左右)发射组成,通过对发光光谱的分析发现,上述两个区域的发射均来自ZnS的缺陷能级。其中,绿色发光峰来源于较低能态的缺陷能级;而高能区域的蓝色发光则是由于高能态的缺陷能级俘获电子的几率增大,在这过程中,PVP形成的能级阶梯有效增加了高能态缺陷能级俘获电子的几率,提升了高能波段的发光效率,相应地,器件的色坐标也随之从(0.37,0.42)变化到(0.30,0.34),趋于白光发射。An electrol （EL） device with structure of ITO//ZnS/SiO2 ： PVP//Al was fabri cated by spin coating with the mixing solution of ZnS/SiO2 quantum dots （QDs） and PVP. The EL emission spectrum consists of green emission in 510--560 nm and weak violet emission around 400 nm. Through analyzing the EL spectrum we find that the above two emissions both come from the defect energy level of ZnS,where the green emission peak is due to the lower defect energy level,while the violet emission is from the higher defect energy level which can trap electrons more easily. During the process, the energy level step formed by PVP can enhance the probability of trapping electrons effectively for the higher defect energy level, the luminous efficiency of higher energy band is increased, and the color coordinate of devices varies from （0. 37,0. 42） to （0.30,0.34） ,approaching to white light emission.

关 键 词：ZnS/SiO2∶PVP复合材料 电致发光(EL) 蓝紫光发射 

分 类 号：O484[理学—固体物理]