High-efficiency black silicon tunnel oxide passivated contact solar cells achieved by adjusting the boron diffusion process

摘要

Optical loss is still a tough problem in photovoltaic; it considerably restrains the conversion efficiency of tunnel oxide passivated contact (TOPCon) solar cells. Black silicon is widely used to enhance light absorption by its light-trapping structure. Paradoxically, the structure simultaneously brings severe carrier recombination and rarely increases efficiency. In our work, we combined the black silicon with TOPCon solar cell and fabricated high-efficiency TOPCon solar cells with nanopore pyramid structure emitter prepared by reactive ion etching. We systematically analyzed the boron doping, emitter passivation, and cell performance. By excellent passivation effect provided by Al_2O_3/SiN_x stacked layers and artificially adjusting boron diffusion process, we successfully fabricated the large-scale (158.75 × 158.75 mm~2) bifacial TOPCon solar cells with short-circuit current density of 40.69 mA/cm~2 and average conversion efficiency of 23.01% with industrial equipment and processes.