Effects Of Injection-Level Dependent Bulk Lifetime On Cell Properties

The injection-level dependent (ILD) lifetime of the silicon bulk material impacts the cell characteristics in multiple and underappreciated ways. Fill factor, FF, is commonly attributed to cell resistances but not to ILD lifetime. Most of the non-ideality behavior, m, and the J(02), of a commercial p-type PERC cell with rear AlOx passivation is directly attributed to the positive sloped ILD lifetime and resistivity. This work demonstrates through theory and experiment various and counter-intuitive aspects of cell metrics originating from the ILD lifetime. Additional cell metrics are proposed to better optimize efficiency.