Differential electroluminescence imaging and the current transport efficiency of silicon wafer solar cells

The current transport efficiency of a solar cell, defined as the fraction of local light-induced current that leads to terminal current increase, is experimentally determined for industrially made crystalline silicon wafer solar cells. Fast mapping is possible by simple differential electroluminescence imaging and the application of a reciprocity relationship. The sensitivity of the current transport efficiency to different components of series resistance is studied through computer finite element analysis. A measurement routine that can quantify the current division to the different metal busbars on the solar cell is proposed to qualify screen printed metal fingers.