发光学报, 2015, 36 (6): 699, 网络出版: 2015-06-25
有机电致发光器件的瞬态电响应特性
Transient Current Response Characteristics of Organic Light-emitting Diodes
有机发光二极管 瞬态电流响应 界面 空间电荷 organic light-emitting diode transient current response interface space charges
摘要
详细研究了有机发光二极管(OLED)在脉冲电压下的瞬态电流响应特性.瞬态响应电流由3部分组成:正向电流峰(IP)、稳态电流(IS)及反向电流峰(IN).研究发现IS为器件工作时通过器件的电流,而IN与IP则分别对应OLED器件电极/有机界面附近的空间电荷的形成及消失过程.IN、IP与脉冲电压成线性关系,阳极的费米能级与空穴传输材料的HOMO能级差导致IN大于IP.利用不同占空比的双脉冲电压研究了电流与空间电荷的关系,发现空间电荷的充分放电临界占空比只受界面接触的影响,而与器件内部结构无关.
Abstract
Detailed transient current response characteristics of organic light-emitting diode (OLED) were investigated.Transient current response curve can be divided into three partitions: positive current spike (IP),stead-state current (IS) and negative current spike (IN).It is found that the positive and negative current peaks correspond to the charging and discharging process of space charges near electrode/organic interface,respectively.Linear relationship between the current spikes and pulsed voltage amplitude is found.Larger IN than IP is induced by the difference between Femi level of electrode and the highest occupied orbital level (HOMO) of organic materials.Different duty-ration dual pulsed voltages are modulated to investigate the relation between current response and space charges.It is found the space charge charging and discharging threshold duty-ration is only depended on the hole injection barrier and independent with internal device structure.
牛立涛, 关敏, 楚新波, 曾一平, 李弋洋, 张杨. 有机电致发光器件的瞬态电响应特性[J]. 发光学报, 2015, 36(6): 699. NIU Li-tao, GUAN Min, CHU Xin-bo, ZENG Yi-ping, LI Yi-yang, ZHANG Yang. Transient Current Response Characteristics of Organic Light-emitting Diodes[J]. Chinese Journal of Luminescence, 2015, 36(6): 699.