High performance front side pastes by Ag precursor equipped glasses

In this study Ag precursor equipped glasses were used to produce model pastes for front side contacts of mc-silicon solar cells. To establish the Ag precursors in the glass, a silver ion-exchange procedure of glass powders is chosen. Suchlike process can be easily integrated in the glass powder production by an additional step whereby the ready milled glass powder is dispersed in a silver salt melt for a certain temperature and time. Pastes containing Ag precursor equipped glass powders show relative efficiency increases up to 43 %. The origin for this increase is seen in two effects. First, the presence of silver ions in the paste glass partly skips the need of silver dissolution in the during the firing and accelerates the silver deposition in the contact interface. Second, a very homogeneous Ag distribution in the contact layer attenuates lateral fluctuations in the local interface reaction progress and therewith the risk of emitter shunting.