Electron-Selective Contacts ATO/LiF/Al-Based High-Performance N-Type Silicon Solar Cells

Due to its excellent passivation and low contact resistivity, Al-doped TiO2 (ATO) has become one of the most promising candidates for dopant-free carriers-selective contacts (CSCs). This work prepares the ATO/LiF/Al electron-selective contacts and applies them to the n-type silicon solar cells as full-area rear CSCs. It is found that 6 nm-thickness ATO thin film possesses the highest minority carrier lifetime of 253.0 mu s on solar-grade Cz n-type wafers, revealing the ultra-low saturated current density J(0) of 120.7 fA cm(-2). Meanwhile, the 6 nm-ATO/LiF/Al electron-selective contact has a significantly low contact resistivity rho(c) of 19.7 m omega cm(2), suggesting a sound electronic transport property of the ATO/LiF/Al stack. Finally, a highest solar cell efficiency of 19.9% is obtained for an n-type crystalline silicon device with a full-area rear ATO/LiF/Al contact. The calculated selectivity S-10 of 13.0 enables the maximum efficiency of 27.3% for the ATO/LiF/Al-based n-type solar cell, demonstrating the great potential of applying this passivating contact in high-efficiency silicon solar cells.

Automated summary

This study develops a novel ATO/LiF/Al electron-selective contact and applies it to the rear of n-type silicon solar cells, achieving good results. By optimizing the contact structure and materials, high minority carrier lifetime and low saturation current density are achieved, resulting in a high solar cell efficiency.