LARGE AREA SCREEN PRINTED N-TYPE MC-SI SOLAR CELLS WITH B-EMITTER: EFFICIENCIES CLOSE TO 15% AND INNOVATIVE MODULE INTERCONNECTION

Abstract

ABSTRACT In this paper we present n-type Si solar cells on large area mc-Si wafers with a boron diffused emitter at the front side. The focus of our studies is mainly related to the front surface of the solar cell. We have optimised BBr3-diffusion and in-situ oxidation with respect to the homogeneity of the sheet resistance and substrate degradation. After diffusion even a slight improvement of the minority charge carrier lifetime was measured, which can be related to Bgettering. The emitter is contacted by AgAl-paste and passivated by thermal SiO2. The development and optimisation of all processes led to solar cells with efficiencies of 14.7% on mc-Si and 17.1% on Cz-Si substrates. In addition to this we present an innovative interconnection of modules using our developed cell (patent pending). We show an alternate serial interconnection of p-and n-type solar cells resulting in easier module processing