terns and light emitting field effect transistors. Further applications includes displays, lighting, photodetectors and photovoltaic energy conversion. Some specific examples include: design of solar cells with enhanced light-to-power conversion and of OLEDs with enhanced light emission, charge transport modeling in organic semiconductor devices from molecular to the device level, charge transport modeling in various organic and hybrid solar cells, and modeling of planar and bulk heterojunction and organic solar cells. Simulations as provided herein can be useful in the layer stack development environment such as in a factory manufacturing OLEDs or solar cells, where emission, current densities, recombination zone thicknesses etc. can be det er mined very quickly and efficiently with the aid of the model. As indicated above, the input specification is of the geometry and composition of the disordered device(s) to be modeled. Here model input parameters such as the mean energy and energy width of the density of states are how composition enters the model. Before performing a simulation, parameter values are included or input in the model/simulation; this defines the problem that is to be solved in the geometry of a device. The input steps for the simulation of the model include input parameters for performing the calculations, define the system, the materials, layer thicknesses, and are used to instruct that the simulation is performed for a selected voltage and/or temperature or for multiple combinations of temperature and voltages. Other device parameters can also be varied in such simulations, such as layer thicknesses. Also as indicated above, the output is simulated transport results. This output can take many forms. For example, the output of the simulation can provide input for use in the process of OLED or solar cell stack development. This facilitates and accelerates processes for developing OLEDs. In another example, the results of the simulation can provide input to assess and permit control of, for example, charge injection, and transport and recombination processes in display technologies such as OLEDs, in addition to advanced optical and electrical characterization techniques and experimental validation. Using the results of the simulations, the technical personal is able to decide before conducting experiments which combination of layers, thickness of layers, and/or the type of materials are best used to design a layer stack for disordered semiconductor devices, and also how to interpret experiments already conducted in terms of parameter values describing processes or materials. The specific output of the simulations can include the current density, position-dependent current density, the