Fully solderable large-area screen-printed Al-BSF p-type Mc-Si solar cells from 100% solar grade deedstock yielding eta > 17 %

A promising alternative to purifying metallurgical grade silicon via the gaseous phase is purification by for example slag refinement, leaching and solidification yielding so-called solar grade silicon (SoG-Si). Despite several advantages of SoG-Si, a wider distribution in PV industry has so far been hindered by reservations towards efficiency potential, reverse bias behaviour, module reliability and material yield. We achieved peak efficiencies over 17 % on standard (15.6×15.6 cm2) industrial fully-solderable screen-printed aluminium back-surface field (SP Al- BSF) solar cells on multi-crystalline silicon (mc-Si) wafers from 100 % Elkem Solar Silicon (ESSTM). To our knowledge, this is amongst the highest efficiencies reported for SP Al-BSF cells on 100 % SoG-mc-Si so far. The average efficiency over an entire brick is 16.6 % which is the same value as for a reference brick from pure polysilicon feedstock. The reverse bias behaviour of all cells appears to be well suited for standard industrial module integration concerning global current density and locally resolved power dissipation behaviour.