Direct-Write Printing of Silver Metallizations on Silicon Solar Cells

Abstract

Direct-write technologies offer the potential for low-cost materials-efficient deposition of contact metallizations for photovoltaics. We report on the inkjet printing of metal organic decomposition (MOD) inks with and without nanoparticle additions. Near-bulk conductivity of printed and sprayed metal films has been achieved for Ag and Ag nanocomposites. Good adhesion and ohmic contacts with a measured contact resistance of 400μΩ•cm2 have been observed between the sprayed silver films and a heavily doped n-type layer of Si. Silver deposited using the MOD ink burns through the Si3N4 antireflection coating when annealed at 850°C to form an ohmic contact to the n-Si underneath. An active solar cell device was fabricated using a top contact that was spray printed using the Ag MOD ink. Inkjet printed films show adhesion differences as a function of the process temperature and solvent. Silver lines with good adhesion and conductivity have been printed on glass with 100 μm resolution.

Low-Cost Inorganic Solar Cells: From Ink To Printed Device

“…Low molecular weight solvents and weakly bound additives enable facile removal under mild conditions (150−200 °C). Similar ink formulations, such as Ag trifluoroacetate in ethylene glycol, have been utilized for direct deposition onto a heated substrate, yielding highly conductive lines without postprocessing . Contacts for CIGS photovoltaic cells were inkjet printed at 200 °C on the ZAO layer.…”

Ink‐Jet Printing, Self‐Assembled Polyelectrolytes, and Electroless Plating: Low Cost Fabrication of Circuits on a Flexible Substrate at Room Temperature

“…Near-bulk conductivity of printed and sprayed metal films has been achieved for Ag and Ag nanocomposites. [18,19] A major challenge in applying a direct ink-jet nanoparticle process is the ink formulation. The inks must contain the appropriate precursors and a carrier compound, and may further contain various binders, dispersants, and adhesion promoters, depending on the nature of the precursor and the particular application.…”

“…Ink composition is critical because it defines the process in which the ink is jetted, the adhesion to the substrate, the line resolution and its profile, and the electronic properties of metal formation. [19] So far, this approach faces the challenge of poor adhesion between the metal film and the substrate; and typically it needs a high temperature (%300 8C) sintering post-process to form the metal thin film for a good electric property. This high-temperature process limits its application, particularly for flexible electronics.…”

Silver Nanoparticles as Pigments for Water-Based Ink-Jet Inks

“…One of them was based on ink containing a reducing agent and receiving material containing the silver salt and, in contrast, on ink and the receiving support containing a silver salt and reducer, respectively. Heating the receiving support during or after the ink deposition resulted in an image formed by silver metal. , Another method is based on ink-jet printing of organometallic precursors dissolved in organic solvent with subsequent conversion of the precursor to metal at elevated temperatures (∼300 °C). − To increase the metal (silver) loading of ink and to obtain higher decomposition rates, silver or other metal nanoparticles may be added to the ink along with the organometallic precursor. Near-bulk conductivity of printed silver films has been achieved with such compositions …”