Observation of the Contact Formation of PV Frontside Pastes by in-situ Contact Resistance Measurement

Ink jet printable silver metallization with zinc oxide for front side metallization for micro crystalline silicon solar cells

“…Obviously, the etching process of the ARC during the firing using the Ag-ink with ZnO particles is considerably slower than using stateof-the-art screen printing pastes. Here usually belt velocities about 200 cm min −1 are applied [5,6]. Nevertheless, by using the investigated Ag-ink with 10 wt.% zinc oxide nanoparticles the contact resistivity reached 8 ± 3 mΩ⋅cm 2 for T zone 4 = 920 °C; therefore ZnO is a promising additive for the metallization of Si-solar cells in the co-firing process for front side metallization using ink jet printing [23].…”

“…During the firing process silver is partially dissolved in the molten glass fraction of the paste [1] and the resulting Ag 2 Ocontaining liquid vitreous phase [26] wets the wafer's silicon nitride layer (ARC). A redox process between dissolved Ag 2 O, ARC and developing SiO 2 leads to the dissolution of the ARC during the firing peak, and the formation of silver precipitates at the interface between metallization and wafer during the cooling [3][4][5]. The flow behavior of the vitreous phase and the silver mass transport are decisive for the contact formation [6].…”

Silver dissolution and precipitation in an Na2O–ZnO–B2O3 metallization paste glass

“…The experiments were designed to keep the heat treatments shorter than necessary for approaching equilibrium states, because dwell times during technical applications using rapid thermal processing (RTP) are rather short, that is, in the range of seconds. 17,19 As well known from silicate glasses, a higher concentration of silver in the glass can be achieved by ion exchange, because the silver solubility is limited using conventional melting technique. 20 However, to incorporate the maximum silver ion concentration is not possible due to the process conditions starting with metallic silver and using short RTP times.…”

“…Most studies were focused on the overall paste performance rather than on the basic understanding of silver‐glass interaction. Independent of the designated use, composition of glasses, morphological properties of silver powders, and applied heat treatments, nano to micro sized silver precipitates were reported in glasses being in contact to metallic silver at enhanced temperatures 5,14–18 . Their formation was explained by dissolution of silver from the powder as ion, stabilization of these ions as part of the glass melt, and final reduction of the ions enabling formation of metallic precipitates.…”

“…In the light of the previous description, the present paper is focused on silver dissolution and precipitation in 19Na 2 O–28ZnO–53B 2 O 3 glasses. The experiments were designed to keep the heat treatments shorter than necessary for approaching equilibrium states, because dwell times during technical applications using rapid thermal processing (RTP) are rather short, that is, in the range of seconds 17,19 …”