High efficiency black silicon Interdigitated Back Contacted solar cells on p- and n-type c-Si substrates

This work demonstrates the high potential of Al2O3 passivated black silicon in high efficiency Interdigitated Back Contacted (IBC) solar cells by reducing surface reflectance without jeopardizing surface passivation. Very low reflectance values, below 0.7% in the 300-1000 nm wavelength range, together with striking surface recombination velocities values of 17 and 5 cm/s on pand n-type crystalline silicon substrates respectively, are reached. The simultaneous fulfillment of both requirements, low reflectance and low surface recombination, paves the way for the fabrication of high efficiency interdigitated back contacted Si solar cells using black silicon at their front surface. Outstanding photovoltaic efficiencies over 22% have been achieved both in pand n-type, 9 cm cells. 3D simulations suggest that efficiencies up to of 24% can be obtained in the future with minor modifications in the baseline fabrication process.