Inkjet Printing for Solar Cell Mass Production on the PiXDRO JETx Platform

Abstract

Inkjet printing is commonly regarded as a promising manufacturing technique for solar cell mass production due to its advantages of non-contact deposition, the ability of creating fine features (~50μm), effective material utilization and high precision. The PiXDRO JETx from Roth & Rau B.V. offers a multi-functional inkjet printing platform that can be configured for various applications, throughputs, substrates, print heads and inks. In this paper we will describe the key product features of the PiXDRO JETx inkjet printing platform. One of these key products features is the ability to combine self-diagnosing printheads with advanced printing strategies to drastically improve the reliability of inkjet printing. The first PiXDRO JETx tool is designed for printing hotmelt or UV-curable inkjet inks. By using a hotmelt masking ink as a plating barrier, 6” heterojunction solar cells with fully plated Ni-Cu front grid are fabricated, demonstrating the functionality of the masking ink in defining a front-grid pattern on the frontside ITO, resulting in finger widths down to 35 μm. A conversion efficiency of 21.6% after stripping of the masking ink shows that the process of printing, plating and stripping is compatible with the heterojunction solar cell process. An investigation in done into the effect of printing strategies, plating height and masking inks with regard to their influence on the lateral growth of the Ni-Cu plated fingers during plating.