Enhanced charge carriers injection by using high-doped silicon in organic-inorganic light-emitting diodes

In general, most polymers are hole-transporting materials, as a result, holes may pass through the emission layer without forming excitons with the oppositely charged carriers and lead to ohmic losses. Furthermore, the recombination zone of holes and electrons is close to cathode where excitons are easily quenched. On the other hand, most inorganic materials have higher electron mobility. Therefore, some attempts have been done to fabricate organic-inorganic heterostucture^[1-4]. The organic-inorganic hybrid EL device is expected not only to permit a wide range selection of emitter and carrier transport materials but also to provide a new approach to construct high-performance EL device taking advantage of both organic and inorganic semiconductors such as high photoluminescence efficiency of organic materials and high carrier density, high carrier mobility and steady chemical property of inorganic semiconductors. What factors influence the emission mechanism of such a device? And what influence its emission performance? In this paper, we attempt to make clear these questions and look forward to finding the factors that influence the emission performance of organic-inorganic hybrid EL devices. In this paper, the emission of organic material inserted between two amorphous silicon dioxides (a-SiO₂) by using high-doped p-type silicon as anode or n-type silicon as cathode has been studied under AC and DC applied voltages. Enhanced charge carrier injection and luminance were observed, which shows high-doped silicon as electrodes can increase the quantity of injected charge carriers. Further, its ability to improve luminance has been studied by changing silicon with different conductance, as well as by varying the thickness of organic and/or inorganic active layers.