Stable Molybdenum Nitride Contact for Efficient Silicon Solar Cells

Carrier-selective passivating contacts play a crucial role in highly efficient silicon solar cells targeting the cost-effective photovoltaic industry. Widely developed hole-selective passivating-contact molybdenum oxide (MoOx) exhibits inferior long-term stability induced by chemical reactions between the MoOx and the adjacent metals. Herein, low-temperature magnetron-sputtering-deposited molybdenum nitride (MoNx) films are developed as stable hole-selective passivating contacts for crystal silicon solar cells. The work function of the MoNx films can be as deep as 5.62 eV featuring a low resistivity of 5.0 x 10(-4) omega cm by optimizing the deposition process. Quasi-metallic MoNx integrated with a MoOx passivating layer is verified to act as effective hole-selective passivating contacts for crystal silicon solar cells, yielding a power convertion efficiency (PCE) above 17%. Although the hole-selective passivation of MoNx films is inferior to fresh MoOx ones, the device performance with MoNx film is kept stable with time in air exposure and surpasses MoOx films after 6 months. The stable performance is ascribed to the metal electrodes diffusion barrier and insusceptible work function of MoNx films compared to MoOx films. This work makes a preliminary exploration to develop efficient crystal silicon solar cells with stable and cost-effective metal nitrides as hole-selective passivating contacts.

Automated summary

In this study, low-temperature magnetron-sputtering-deposited molybdenum nitride (MoNx) films were developed as stable hole-selective passivating contacts for crystal silicon solar cells, featuring a deep work function of 5.62 eV and low resistivity. When integrated with a MoOx passivating layer, MoNx proved to be effective in improving the power conversion efficiency of solar cells above 17%. The stable performance of MoNx films was attributed to its metal electrodes diffusion barrier and insusceptible work function, surpassing MoOx films after 6 months of air exposure.