Impact of Selective BSF on Performance of Bifacial nPERT Cells with Ni/Ag Co-Plated Contacts

8 Pages Posted: 29 Mar 2018 Last revised: 20 Apr 2018

See all articles by Loic Tous

Loic Tous

Interuniversity MicroElectronics Center - IMEC

Richard Russell

Imec vzw

Emanuele Cornagliotti

Imec vzw

Arvid van der Heide

Imec vzw

Filip Duerinckx

Imec vzw

Jozef Szlufcik

Imec vzw

Date Written: April 15, 2018

Abstract

In this work, we evaluate the impact of implementing a selective back surface field (BSF) on the performance of bifacial n-type Passivated Emitter and Rear Totally diffused (PERT) cells with Ni/Ag co-plated contacts. For this, we compare bifacial nPERT cells featuring a homogeneous BSF etched-back to ~100 Ω/sq and patterned by laser ablation to cells featuring an identical front side design and a selective BSF obtained by means of laser doping. In the first part of this paper, we demonstrate using test structures that selective BSF cells benefit from drastically lower area weighted recombination current density (J0) contributions at the BSF side resulting in estimated Voc improvement from ~657 mV to ~ 681 mV. In the second part of this paper, we confirm at cell level that implementing a selective BSF results in gains in Voc ~ 30 mV, jsc~ 0.2 mA/cm2, and Fill Factors FF ~ 0.9%abs. resulting in average cell efficiencies improving from 20.7±0.4 % to 22.0±0.2 %. This clearly confirms that a selective BSF is required in nPERT cells with Ni/Ag co-plated contacts to maximize cell efficiencies. Finally, we fabricated a 9-cells bifacial glass-glass laminate for proof-of-concept and discuss several possible improvements to bring 60-cells module front maximum power values under standard test conditions (STC) above 340 Wp.

Keywords: bifacial, nPERT, plating, SWCT.

Suggested Citation

Tous, Loic and Russell, Richard and Cornagliotti, Emanuele and van der Heide, Arvid and Duerinckx, Filip and Szlufcik, Jozef, Impact of Selective BSF on Performance of Bifacial nPERT Cells with Ni/Ag Co-Plated Contacts (April 15, 2018). 7th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, 2017. Available at SSRN: https://ssrn.com/abstract=3152414 or http://dx.doi.org/10.2139/ssrn.3152414

Loic Tous (Contact Author)

Interuniversity MicroElectronics Center - IMEC ( email )

B-3001 Leuven
Belgium

Richard Russell

Imec vzw ( email )

Kapeldreef 75
Leuven, 3001
Belgium

Emanuele Cornagliotti

Imec vzw ( email )

Kapeldreef 75
Leuven, 3001
Belgium

Arvid Van der Heide

Imec vzw ( email )

Kapeldreef 75
Leuven, 3001
Belgium

Filip Duerinckx

Imec vzw ( email )

Kapeldreef 75
Leuven, 3001
Belgium

Jozef Szlufcik

Imec vzw ( email )

Kapeldreef 75
Leuven, 3001
Belgium

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