利用激子探测层研究有机电致发光器件的激子分布

Dectection of Exciton Distributionsin Organic Light Emitting Diodes Utilizing Exciton Sensing Layer

通过改变磷光染料PO-01超薄层在Tc Ta/Tm Py PB中的插入位置,制备了结构为ITO/Mo3/Tc Ta/Tm Py PB/Li F/Al的有机电致发光器件.器件中激子主要分布在Tc Ta/Tm Py PB界面附近很窄的区域内,并且界面附近激子相对浓度随电流密度增强而增大.另外,PO-01超薄层插入位置逐渐远离有机异质节界面,器件的电流效率显著下降.因此,有效利用载流子复合区产生的激子,并将发光区限制在一定区域内是影响器件发光效率的重要因素.

The organic light emitting diodes （OLEDs） with the structure of ITO/Mo3/TcTa/TmPyPB/LiF/A1 while employing an ultra-thin layer of PO-01 into TcTa/TmPyPB whose emission intensity is proportional to the local density of excitons at several locations within the device are demonstrated. It is found that excitons are mainly distributed at the interface of TcTa/TmPyPB. In addition, the relative concentration of exciton at the interface increases with increasing of current density. The current efficiency decreased significantly while the PO-O1 ultrathin layer is gradually away from the interface of organic heterojunction. Therefore, an efficient harvest exciton confined to the electron-hole recombination zone is a major factor affecting the luminous efficiency.