By Matthias Demant, Theresa Strauch, Jonas Haunschild & Stefan Rein, Fraunhofer ISE; Kirsten Sunder & Oliver Anspach, PV Crystalox Solar Silicon
With the transition of the cell structure from aluminium back-surface field (Al-BSF) to passivated emitter and rear cell (PERC), the efficiency of multicrystalline silicon solar cells becomes more and more sensitive to variations in electrical material quality. Moreover, the variety of multicrystalline materials has increased with the introduction of high-performance multicrystalline silicon. For these reasons, a reliable and verifiable assessment of the electrical material quality of multicrystalline wafers gains importance: to this end, a rating procedure based on photoluminescence imaging has been developed.
