Latest efficiency results with the screenprinting technology and comparison with the buried contact structure

A lot of progress has been made in the pilot-production of mono- and multicrystalline silicon solar cells by the screenprinting technology. For example, a screenprinting process using new metal pastes, fine linewidth printing, the incorporation of surface passivation, Al gettering, BSF and a selective emitter structure yields efficiencies over 17% on 100 cm/sup 2/ Cz-Si material. These results ask for a detailed comparison concerning the relative performance of state-of-the-art screenprinted cells compared to the state-of-the-art buried contact structure. This is done by means of 2D-simulations using the simulation program SIMUL. The efficiency difference between a buried contact technology and a screenprinting technology, both with selective emitter and good surface passivation, is only 0.5-0.6% absolute. The efficiency difference between screenprinted cells with a homogeneous emitter and buried contact cells with a selective emitter turns out to be 1% absolute, provided a good surface passivation is applied. Looking at the above-mentioned difference in efficiency, only detailed cost calculations for an industrial production scenario can reveal which process leads to the lowest cost per Wp.