Characterization of Silicon Heterojunctions on Multicrystalline Absorbers Using Injection-Dependent Photoluminescence Imaging

Multicrystalline silicon solar cells composed of silicon heterojunctions and a transparent conductive oxide show various characteristics only visible through spatially resolved and injection-dependent measurements. Injection-dependent photoluminescence imaging calibrated with the quasi-steady-state photo conductance technique was used to visualize such effects caused by the interaction between the transparent conductive layer, the silicon heterojunction and the multicrystalline silicon absorber. By this means bulk recombination as well as passivation quality of the heterojunction could be locally analyzed. Shunting effects could be revealed, as well as implications on pseudo fill factors of locally different regions within the multicrystalline absorber. A comparison with Suns-Voc measurements shows that the contactless method of injection-dependent photoluminescence imaging (Suns-PLI) offers an appropriate method for characterizing this solar cell concept.