Spatially Resolved Electrical Parameters of Si Solar Cells Using Quantitative Lock-In Carrierography

Electrical parameters (saturation current density and local series resistance) are critical to solar cells. In this work, 2-dimensional finite-element simulations were carried out to study the influence of local distributions of electrical parameters and broken fingers on luminescence images at various working conditions. The relationship between luminescence intensity and local diode implied voltage was identified by simulation results and also by lock-in carrierography/photoluminescence measurements on a silicon solar cell. Spatially resolved saturation current density (J₀) and local series resistance (R_s) of the Si solar cell were realized by LIC. Influences of broken fingers on J₀ and R_s were discussed. The LIC measurements were in accordance with 2D simulation results. The experiment results show that LIC, as a quantitative luminescence-based methodology, can be able to spatially resolve electrical parameters of silicon solar cells and PV modules.