Based on the model of microcavity theory and transfer matrix theory, we measured the influence of complex cathode by introducing dielectric layer. Dielectric layer greatly influence the property of microcavity. Complex cathode may have obvious improvement to the trait of microcavity. Both in the instances considering microcavity effect and not considering, we compared the reflectivity, phase of reflection and light outcoupling efficiency of complex cathode with that of single layer metal cathode. To make the model simple, we do not consider complicated effect induced by interface absorbance and combination, we got the greatest improvement to outcoupling efficiency at certain instance. The efficiency of optimum structure is twelve times higher than that of single metal layer cathode. This confirms that dielectric layer can be used to improve the performance of organic metal cavity devices. Based on this kind of structure, unsymmetrical metal may reach great application.
Microcavity structures are widely utilized as resonators in many optoelectronic devices to improve their optical performance. We present an analytic approach to study the angle-dependent properties in active microcavities with dielectric Bragg reflectors. Based on the hard mirror (HM) model and paraxial propagation approximation, the angle dependent resonance properties can be expressed analytically in virtue of the cavity parameters and incident angle. Making use of these expressions, we found both the position of the active layer and the configuration of dielectric Bragg mirrors contribute to the angular characteristics of resonance in the active microcavity. The varying trend of the standing wave effect, intracavity electrical field and the degradation of quantum efficiency due to different incident angle are discussed in detail. It's found that there exists an optimal cavity configuration where the enhanced intracavity resonance can keep high value within a broader incidence range. Then further performance optimization of the whole devices can be performed.
Soluble poly(phenylene vinylene)(PPV)-type polymers have been applied widely as active layers in many optoelectronic devices, such as light-emitting diodes and organic lasers. In such devices their physical thickness are commonly about 100~200 nanometers for the desirable charge transport characteristics and optical interference effects. In this work, poly[(2-methoxy,5-octoxy) 1,4-phenylenevinylene] (MO-PPV) thin films have been prepared from their chloroform solutions of different concentrations. Then their UV-VIS absorption (Abs), photoluminescence (PL) and selective-excitation photoluminescence (SEPL) spectra have been measured at room temperature. A long wavelength emission component near 630 nm has been identified as S2→S0 vibronic band through gaussian decomposition method and confirmed by experiments. The effect of annealing on the optical properties of MO-PPV thin films is also studied. The results show that there exists an optimal treatment temperature under which the maximal excitation intensity can arrive. It can be attributed to the different morphologies in films. In addition, an experimental research about the active polymer photonic well structures of MO-PPV/PMMA pairs has been carried out.