The aim of this doctoral thesis is to advance in the knowledge of electroluminescent devices characterized by the emission of light within a photoactive layer as result of the transport and recombination of electrical charge. The thesis is divided in two different parts. 
      The first one is focused on the design and construction of electronic equipment that allow the electrical characterization and light emission measurements of new electroluminescent devices consisting of hybrid organic-inorganic particulate materials. In contrast to preindustrial OLEDs devices based on the emission of organic polymers and having high light output efficiencies, there is an interest in developing new materials that initially and before optimization would present a much lower intensity emission and for which there are no electronic measuring devices sensitive enough for their characterization. In particular in this first part we have built a system for electrical characterization which allows to perform electric measurements of particulate films at controlled pressure, temperature, and humidity. Also, it has been carried out the modification of a commercial fluorescence equipment to adapt it for the measurement of thin electroluminescent films with efficiencies below 1cd/m2. The electrical characterization of a series of luminescent hybrid materials has been carried out with these home-made equipments in order to understand the operating mechanisms of these supramolecular systems.
The second part of the thesis has been directed at developing a model based on the electrical simulation software “SPICE” able to stablish models for the Luminance (L), Current (I), Voltage (V) and Temperature (T) behavior of preindustrial large area OLED panels suitable for general lighting applications. In particular three models of increasing complexity where implemented (one-dimensional electric model, 3D electric model at operating point, and extended 3D electric model). The thesis also describes those procedures and measurements needed to achieve the values of the input parameters to these models. With the values thus obtained several preindustrial OLEDs panels were simulated and compared with the experimental data of real panels in order to validate the model. To establish the validity of the model under different conditions four panels of different sizes and composition were tested. Subsequently, a series of predictive simulations were carried out in such a way that light homogeneity of the panels was improved. This was done through two simulations in which we varied the nature of the encapsulation cover and the inert gas that is tipically introduced inside the OLEDs in order to protect the devices from the attack of oxygen and moisture. The substitution in the model of the cover and gas with components of higher thermal conductivity reduces drastically the effects of inhomogeneity due to temperature. Thus, the model predicts that the behavior of OLEDs with improved thermal conductivity should be like the ones that takes place when the panel is powered up with pulsed current where effects caused by temperature are negligible and the panel homogeneity is only affected by the anode and cathode resistance.