Developed by researchers at the University of New South Wales (UNSW) in Sydney, the patented technology enables PL images to be measured with acquisition times less than 1 s,1 Only a few years after its introduction, research institutes and silicon wafer and solar cell manufacturers worldwide use commercial PL imaging equipment, which is offered by BT Imaging, a UNSW spin-off company.2 How it works In PL imaging of silicon samples, the entire surface of the sample - typically 156 ? 156 mm - is illuminated homogeneously. Systematic PL imaging inspection of silicon wafers and automatic assessment of metrics derived using image-analysis methods allow cell performance to be predicted at the start of cell manufacturing - a unique opportunity enabled for the first time by fast PL imaging.5, 6> 7 Analyzing PL on silicon wafers from bottom to top of a silicon brick also enables the 3D distribution of defects within a brick to be measured, valuable information for gaining understanding and better control of the crystallization process.