Large-area n-type silicon solar cells with printed contacts and aluminium-alloyed rear emitter
We have further improved our n-type silicon solar cells with full-area screen-printed aluminiumalloyed rear p+ emitter. For our laboratory-type n+np+ back junction solar cells (4 cm2) featuring a high-efficiency front side with evaporated contacts, we have optimised the rear Al-p+ emitter and the phosphorus-diffused n+ front surface field including the antireflection coating. Thereby, we have obtained an increase in the open-circuit voltage of around 15 mV, resulting in excellent Voc values for this cell structure above 640 mV and cell efficiencies of 19.8 %. By applying an industrially feasible front metallisation of aerosol-printed and silver-plated contacts, we have successfully demonstrated the upscaling of our cells to large areas. For our best industrial-type n+np+ solar cell with front and rear printed contacts, we have achieved a record-high efficiency of 18.2 % (148.5 cm2) on n-type phosphorus-doped 10 ?cm monocrystalline silicon material.