Münster 1999 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 2: Photovoltaik I

HL 2.3: Vortrag

Montag, 22. März 1999, 11:00–11:15, H1

Grain boundary contacting of multicrystalline silicon solar cells — •Michael Radike and Johann Summhammer — Atominstitut Wien, Stadionallee 2, A-1020 Wien, Austria

The electronic properties of multicrystalline silicon are heavily influenced by impurities concentrated along grain boundaries, e.g. some increase the recombination activity. Dopants also can diffuse preferentially down the grain boundaries which leads to a low resistance path down the grain.

Both effects decrease the efficiency of multicrystalline silicon solar cells. Another decrease in efficiency comes from the metallic front contact grid because it shades off part of the cell.

We present a new way to combine the grain boundaries and front contact grid in order to reduce the losses of multicrystalline silicon solar cells:

The different grain boundaries of a multicrystalline silicon wafer are detected down to a certain grain size (approximately 1mm*) using a flat bed scanner and a specially developed software. Onto these grain boundaries the metallic ink is printed with an ink jet printer. As a result one gets a low-cost possibility to increase the efficiency of multicrystalline silicon solar cells. We present a first analysis of the characteristics of wafers processed in this manner.