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Keywords:

Science & Technology, Technology, Physical Sciences, Energy & Fuels, Materials Science, Multidisciplinary, Physics, Applied, Materials Science, Physics, 02 Physical Sciences, 03 Chemical Sciences, 09 Engineering, Energy, 34 Chemical sciences, 40 Engineering, 51 Physical sciences

Abstract:

The compensatory behaviour of open-circuit voltage (V(oc)) and short-circuit current (J(sc)) in function of the base resistivity of multicrystalline silicon (Polix) solar cells (4 cm2) is investigated. Thin substrates (200 mum) with base resistivities between 0.2 OMEGA.cm and 2.5 OMEGA.cm (boron doped) are used in a laboratory high efficiency process (including Back Surface Field, hydrogen and oxide passivation, selective and homogeneous emitters) to test the limits, in terms of V(oc) and J(sc), that can be reached on this material. On low resistivity substrates (0.2 OMEGA.cm) a record value of 640 mV (independently confirmed by NREL) is achieved for the open-circuit voltage which largely compensates for the relatively small decrease in J(sc). This high value of V(oc) resulted in a cell efficiency of 16.8%. It is found that provided efficient hydrogen passivation treatments are performed on the solar cells, the efficiencies of solar cells fabricated on the lower resistivity substrates are larger than those achieved on the higher resistivity material.