Luminescence and current-voltage characteristics of solar cells and optoelectronic devices

Abstract

The transduction and conversion of light into work via a quantum process is dependent on the luminescent properties of the materials involved. Materials that can exhibit emission of light upon illumination are likely candidates for solar cells, detectors and optoelectronic devices. This radiative recombination in a material is directly related to the output device parameters, such as the current voltage characteristics. The chemical potential of the incoming light is a function of the photon energy and incident radiance. The maximum amount of work per particle, or voltage, that can be extracted by a solar converter is shown to be equal to chemical potential of the excitation, which can be inferred from the photoluminescence efficiency at ambient temperature. A discussion is made as to the use and optical properties of materials such as Si, GaAs, FeS2, and organic dyes as efficient solar cell materials. In particular, the silicon I–V curve and luminescence are evaluated using the model, and shown to correspond to measured devices. A discussion is also made as to the extension of the luminescence model to the understanding of the light emitting diode, or LED. By allowing the absorber to remain as thin as possible, lower recombination fluxes and higher voltages are possible in solar cells and detectors.