Efficiency enhancement of i-PERC solar cells by implementation of a laser doped selective emitter

• Published in: Solar energy materials and solar cells Vol. 134; pp. 89 - 98
• Main Authors: Hallam, Brett, Urueña, Angel, Russell, Richard, Aleman, Monica, Abbott, Malcolm, Dang, Chi, Wenham, Stuart, Tous, Loic, Poortmans, Jef
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2015
• Subjects: Doping; Emittance; Laser ablation; Laser doping; Lasers; Open circuit voltage; PERC; Photovoltaic cells; Plated contacts; Platforms; Selective emitter; Solar cells; Solar energy; Selective emitter; Plated contacts; PERC; Laser ablation; Laser doping
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2014.11.028

In this work, we present the incorporation of a laser doped selective emitter into the i-PERC platform at Imec using large area magnetically confined boron-doped Czochralski grown silicon wafers. Cells were fabricated with self-aligned plated n-type contacts with a comparison between the use of a homogenous emitter with contact openings formed by picosecond laser ablation and a selective emitter formed by laser doping with a mode-locked UV laser using various processing speeds. Without modification to other processes in the i-PERC platform, improvements in efficiency of approximately 0.4% absolute were obtained with the inclusion of the selective emitter structure through improvements in open circuit voltage, fill factor and reduced series resistance. This resulted in peak efficiencies of 20.5% using a processing speed for laser doping of 5m/s.
•0.4% absolute efficiency enhancement by the incorporation of a laser doped selective emitter into a PERC cell structure.•Peak efficiency of 20.5% obtained.•Faster processing speeds (>2m/s) observed to cause less bulk damage than slower processing speeds.