Red long lasting phosphorescence（LLP） was firstly observed in LaA103：Eu3＋ phosphor synthesized by solid state method at 1773 K. It reveals that the Eu3＋ ions occupy the asymmetric La3＋ sites, resulting in the orange-red emission of Eu3＋. The LLP of the optimum LaA103：0.6%Eu3＋ sample can come to about 2000 s according to a definition of 0.32 mcd/m2. The LLP decay curve can not be fitted even by a function of three exponential terms, due to the complicated retrapping process of carriers. The result of a classical multi-peak fitting method on thermo- luminescence reveals that the excellent LLP performance of LaA103：Eu3＋ material originates from the rich distribu- tion of shallow traps（E=0.7875 eV）.
By utilizing a two-step process to express the charge generation and separation mechanism of the transition metal oxides （TMOs） interconnector layer, a numerical model was proposed for tandem organic light emitting diodes （OLEDs） with a TMOs thin film as the interconnector layer. This model is valid not only for an n-type TMOs interconnector layer, but also for a p-type TMOs interconnector layer. Based on this model, the influences of different carrier injection barriers at the interface of the electrode/organic layer on the charge generation ability of interconnector layers were studied. In addition, the distribution characteristics of carrier concentration, electric field intensity and potential in the device under different carrier injection barriers were studied. The results show that when keeping one carrier injection barrier as a constant while increasing another carrier injection barrier, carri- ers injected into the device were gradually decreased, the carrier generation ability of the interconnector layer was gradually reduced, the electric field intensity at the interface of the organic/electrode was gradually enhanced, and the electric field distribution became nearly linear： the voltage drops in two light units gradually became the same. Meanwhile, the carrier injection ability decreased as another carrier injection barrier increased. The simulation re- sults agree with the experimental data. The obtained results can provide us with a deep understanding of the work mechanism of TMOs-based tandem OLEDs.
