21.3%-Efficient n-type silicon solar cell with a full area rear TiO2/LiF/Al electron-selective contact
Wenjie Wang1,2, Jian He2, Di Yan2, Chris Samundsett2, Wenzhong Shen1, James Bullock3, Yimao Wan2
1Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
/2Research School of Engineering, Australian National University, Canberra, Australia
/3School of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Australia

In this work, we investigate an effective passivating electron-selective TiO2/LiF/Al contact with low contact recombination and resistivity. It is shown that as-deposited 4 nm TiO2 films provide the best characteristics with a minority carrier lifetime of 3.03 ms and a contact resistivity of 18 mΩ·cm2, comparing to other conditions. The low contact resistivity is attributed to band bending from the low work function LiFx/Al stack. A champion efficiency of 21.32% has been achieved for an n-type silicon solar cells a with full-area rear TiO2/LiF/Al contact, demonstrating the excellent potential of this contact for fabricating high efficiency silicon solar cells.