Wang, JialiRen, JinleiCreon, LauraPeres, PaulaChemnitzer, ReneCorre, Pierre YvesPhang, Sieu PhengMacdonald, DanielLiu, An Yao2026-06-112026-06-11https://hdl.handle.net/1885/733810376The fabrication of localized doped polycrystalline silicon (poly-Si) passivating contacts, such as in an interdigitated back contact (IBC) solar cell, is complex and costly. Inkjet printing offers a promising route to simplify this process; however, unintended doping and cross-doping from the liquid dopant sources remain a significant challenge. This study demonstrates the effectiveness of a spin-on SiOx capping layer in suppressing unintended doping in unprinted regions and cross-doping between dopant species, enabling the simultaneous formation of localized n+ and p+ poly-Si passivating contacts using inkjet printing via a single high-temperature annealing step. Secondary ion mass spectrometry (SIMS) mapping reveals uniform doping concentrations within the printed lines, approximately 1 × 1020 cm−3 for phosphorus and 2 × 1020 cm−3 for boron in the poly-Si layers with minimal lateral diffusion at the line edges. More importantly, unintended doping is now reduced to below 9 × 1017 cm−3, just 0.5% of the source doping concentrations. Additionally, cross-doping in the printed region of opposite polarity remains below 5 × 1018 cm−3, which is less than 2.6% of the intended doping. These results pave the way for the potential adoption of inkjet printing in simplifying the fabrication of solar cells and other electronic devices.This work has been supported by the Australian Renewable Energy Agency (ARENA) through projects 2017/RND017 and 2022/TRAC004, as well as the Australian Center for Advanced Photovoltaic (ACAP). The authors thank Dr Zhongshu Yang for assistance with laser cutting SIMS samples.enPublisher Copyright: © 2026 The Author(s). Advanced Materials Technologies published by Wiley-VCH GmbH.auto-dopingcross-dopinginkjet printinginterdigitated back-contact solar cellsliquid doping sourcelocal dopingTOPCon silicon solar cells202610.1002/admt.202501503105035192288