SPICE modelling of photoluminescence and electroluminescence based current-voltage curves of solar cells for concentration applications

Abstract

Quantitative photoluminescence (PL) or electroluminescence (EL) experiments can be used to probe fast and in a non-destructive way the currentvoltage (IV) characteristics of individual subcells in a multi-junction device, information that is, otherwise, not available. PL-based IV has the advantage that it is contactless and can be performed even in partly finished devices, allowing for an early diagnosis of the expected performance of the solar cells in the production environment. In this work we simulate the PL- and ELbased IV curves of single junction solar cells to assess their validity compared with the true IV curve and identify injection regimes where artefacts might appear due to the limited in-plane carrier transport in the solar cell layers. We model the whole photovoltaic device as a network of sub-circuits, each of them describing the solar cell behaviour using the two diode model. The subcircuits are connected to the neighbouring ones with a resistor, representing the in-plane transport in the cell. The resulting circuit, involving several thousand sub-circuits, is solved using SPICE.