Advanced Characterisation of Silicon Wafer Solar Cells

Abstract

Advanced characterisation plays an important role for further improvements of the cost effectiveness ($/Wp) of solar cells. This paper presents an overview of advanced characterisation techniques that are presently being used for the analysis of silicon wafer solar cells, either in the laboratory or in the factories. Techniques covered include luminescence imaging, lifetime spectroscopy, and optical and electrical measurements. We present a detailed loss analysis, entirely based on measured parameters, that quantifies the main loss processes in silicon wafer solar cells. This loss analysis is completely based on high-precision measurements and provides a detailed quantification (in W/cm2) of the power losses of the solar cell due to front metal shading, front surface reflection of the active area, front surface escape, series and shunt resistance, non-perfect active-area internal quantum efficiency, and the forward-bias current at the one-sun maximum power point. We also show that a thorough characterisation of the individual processing steps and a detailed loss analysis of the final solar cells can be used to improve the average efficiency and yield of industrial silicon wafer solar cells.