【摘要】 为探讨洞悉电场对有机发光二极管电致荧光量子效率的影响,通过激发-探测超快光谱技术研究了激子在电场下的瞬态行为.与单重态激子相应的激发态在230μJ/cm2激发强度下,显示了快慢两个弛豫过程.快慢组分的权重因子及快组分弛豫时间常数是电场相关的,在6.4×105V/cm的电场下,与无偏置电场相比,激子的快组分弛豫时间加速,快组分的权重因子由22%增加为72%,约50%的初始激子又通过电场而离解.慢组分是电场无关的,其弛豫时间常数为890ps.实验结果还揭示了由激发光所产生的长程声学声子,其声速为17/ps.更多还原

【Abstract】 To gain an insight into the effect of electric field on the electro-luminescence of organic light emission diode,the ultrafast pump-probe spectroscopy is used to investigate the transient phenomena of the excitons induced by the electric field.Under the excitation density of 230 μJ/cm2,the decay of the singlet excitons shows a fast and a slow component.The amplitude factor and the relaxation time of fast component are field-dependent.Compared with the zero biascase,the relaxation time of the fast component becomes faster at a bias of 6.4×105 V/cm,its amplitude factor is increased from 22% to 72%,about 50% initial excitons are dissociated by the electric field.The slow component is field-independent,its relaxation time-constant is about 890 ps.The longitudinal acoustic phonons with sound velocity of 17/ps generated by excitation pulse are observed.更多还原