Generalised distributed model of a solar cell: Lateral injection effects and impact on cell design and characterisation

Increasing insights into the operational features of experimental solar cells, particularly the effects of spatial variations arising from material quality fluctuations or device design features, are being made possible by advanced characterisation technologies, such as luminescent imaging. A widely used two-dimensional model of solar cells underpinning the interpretation of such effects consists of a network of distributed elemental solar cells connected by resistive elements. This model is refined to account rigorously for lateral carrier and photon flows in the cell bulk by incorporation of a network of pseudo-current sources. An example of the use of the new model is given by analysing the lateral injection effect due to voltage variation along the emitter under operating conditions. The derived results not only provide a more general insight into such a lateral injection mechanism, but also reveal the impact on luminescent imaging.