Welcome to the 4th edition of the NextBase project newsletter

The NextBase project has entered its 30th month. We had a successful fifth general assembly (GA) meeting at EGP in Catania in October 2018. The project is currently proceeding mostly according to schedule. After screening a number of different contacting materials, e.g. silicon and its alloys, transition metal oxides, transparent conductive oxides and metals, contact resistance for both polarities below 50 mOhm.cm2 were demonstrated, as well as front-side passivation strategies allowing lifetime at 1.1015 cm-3 above 10 ms and extremely low parasitic absorption. As of December 2018, shadow-mask-based IBC-SHJ devices based on the tunnel IBC concept demonstrated up to 24.8 % efficiency, photolithography-based ones up to 23.3 %, and laser-based ones up to 22.5 %. On the industrial prototype PECVD reactor for IBC-SHJ solar cells developed in this project, efficiencies up to 24.4% on a cell size of 90.25 cm² were demonstrated using fully industrial feasible tunnel IBC shadow-masking approach. In the last months to come, the consortium is working intensively on reaching the targeted cell efficiency value of 26% and on scaling up the cell size to the M2 size. Module material and technology development in the project allows to report an IBC-SHJ module efficiency of 22.5% based on 23.2% cell efficiency using smart wire connection technology (SWCT) as interconnection. This module reaches a cell-to-module (CTM) power ratio of 96.9% with indications for further increase to above 98% with slight adaptations.

In this newsletter, we want to highlight 4 key topics in the NextBase project: 1) Advanced silicon wafer preparation; 2) Novel layer stacks and contact materials; 3) IBC-SHJ process integration for mass production and 4) cost and life-cycle analysis.