Presentation Details
| Microscopic Analysis of LECO-induced Modification of Ag-Polysilicon Contact Interface in Double-Side TOPCon Solar Cells (yes) Wook-Jin Choi, Young-Woo Ok, Kwan Hong Min, Sagnik Dasgupta, Ruohan Zhong, Ajeet Rohatgi. Georgia Institute of Technology, Atlanta, GA, USA |
Abstract
Double-side TOPCon solar cells offer a promising pathway to surpass the efficiency limits of conventional n-TOPCon solar cells; however, their performance is often constrained by the high contact resistivity (ρc) and metal-induced recombination current (J0,met) at the hole-selective p-TOPCon layer. In this work, we demonstrate that laser-enhanced contact optimization (LECO) effectively decouples contact resistivity (rc) from firing temperature in DS-TOPCon solar cells. LECO achieves low rc of ~0.4 mΩ-cm2 for textured n-TOPCon and ~2.6 mΩ-cm2 for planar p-TOPCon at firing temperatures 30–50 °C lower than typical industrial firing conditions. Plan-view scanning electron microscopy (SEM) reveals direct evidence of LECO-induced electrochemical reactions at the Ag-polysilicon interface, including enlargement of embedded Ag crystallites, agglomeration of colloidal Ag nanoparticles, and formation of localized current-fired contacts (CFC). Notably, these interface modifications are consistently observed on both front and rear TOPCon surfaces, indicating a common underlying mechanism. By combining LECO with low-temperature firing, we achieved 23.2%-efficient rear-junction DS-TOPCOn solar cells. Furthermore, device simulations indicate that efficiencies exceeding 26% are attainable using readily available advanced technologies, highlighting the strong potential of DS-TOPCon cell structures enabled by LECO.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.