Effects of silver nanoparticles on the firing behavior of silver paste on crystalline silicon solar cells

Abstract

• Ag nanoparticles promote the firing of silver paste on c-Si solar cells. • A continuous layer of Ag precipitates at the interface between glass frit and Si. • Ag nanoparticles reduced the contact resistance of silver paste on c-Si solar cells. • Firing mechanism of Ag nanoparticle-aided silver paste is proposed. We synthesized silver nanoparticles (AgNPs) with a diameter ranging from 300 to 800 nm by chemical reduction, added them into commercial silver paste used for the front-contact metallization of crystalline Si (c-Si) solar cells, and investigated the effects of AgNPs on the firing behavior of the silver paste on c-Si solar cells by differential scanning calorimetry, electron scanning microscopy, and contact resistance measurement. It was observed that surface sintering of AgNPs occurred at a lower temperature compared with that of micrometer-sized Ag particles in commercial silver paste. With the assistance of AgNPs, more Ag + ions were dissolved in fluidized glass frit during the firing process of the paste, and a continuous layer of Ag was reduced and deposited between glass frit and Si substrate. The Ag layer enhanced electrical conduction and decreased the specific contact resistivity of the paste on c-Si solar cells. Thus, a firing mechanism of AgNP-aided silver paste was proposed. The experimental data demonstrate that AgNPs can be used to improve the properties of the fired paste on c-Si solar cells and AgNP-aided silver paste is a promising material used for the front-contact grids on c-Si solar cells.