Recombination Analysis of Maxeon IBC Production Cells by Time-Resolved Photoluminescence

Photoluminescence is a powerful technique to analyze solar cell recombination across the manufacturing steps. However, this analysis requires accurate modelling of the phenomena caused by injection-dependent lifetimes. We present a transient photoluminescence technique that we apply to our current new-generation production cells. We extract the saturation current Jo and the bulk lifetime, in a refined version of the method developed by Kane and Swanson. We include band-gap narrowing effects occurring at the large operating voltages typical of our back-contact cells. Our approach results in excellent fittings of the carrier density decay (R
²
=99.9%). We find an area averaged J
o
of 6.2 fA/cm
²
and an inverse bulk Shockley-Read-Hall lifetime of 14 s
⁻¹
in a production cell measured after metal etching.