Figure 4
Bias-dependent shifts of important parameters.
(a) Equilibrium densities of singlet exciton (SE) (NS,e) and triplet exciton (TE) (NT,e) normalized at 5 V. (b) Conversion-efficiencies normalized at 5 V of SE and TE calculated by the EL- and BM-intensity divided by current measured simultaneously vs. applied voltages. The horizontal dotted line indicates the mean value for TE. (c) Relative ratio of the generation rate of SE to that of TE normalized at 10 V versus applied voltage. The solid curve indicates the best-fit result according to equation (4). The inset indicates the generation efficiencies of SE and TE vs. voltage obtained from the best-fit result of (c). (d) Ratio of the EL-intensity measured through the anode (ITO) to that through the cathode (Ca:Al) normalized at 10 V. The EL intensities were simultaneously measured using two photo-diodes set facing the anode and the cathode sides.
