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Presentation Details
| Ag-free Solar Cell Featuring Passivating Contacts with Screen-printed Front Al and Rear Cu Contact with Laser-enhanced Contact Optimization Ruohan Zhong1, Byungsul Min2, Vijaykumar Upadhyaya1, Sebastian Junge2, Young Woo Ok1, Brian Rounsaville1, Rolf Brendel2, Ajeet Rohatgi1. 1Georgia Institute of Technology, ATLANTA, GA, USA.2Institute for Solar Energy Research Hamelin, Emmerthal, Germany |
Abstract
The increasing consumption of silver (Ag) and its associated cost remain a challenge in scaling photovoltaic manufacturing toward more than terawatt/year level. Recently, 24.2% POLysilicon on Oxide (POLO) back junction solar cell has been reported by ISFH, showing the success of integrating aluminum contact with p-substrate on the front with laser contact openings in combination with Ag-contacted n-polysilicon (poly-Si) on the back. Additionally, 24.3% Tunnel Oxide Passivating Contact (TOPCon) front junction cell on n-type substrate has been reported in GIT with screen-printed copper (Cu) contacted n+ polysilicon on the back and Ag contacted boron emitter on the front. Since Al and Cu contacts have been independently proven compatible with p-type surface and n-type doped polysilicon, respectively, their combination can enable a fully Ag-free solar cell with polysilicon passivating contacts. In this work, we demonstrate for the first time Ag-free POLO/TOPCon solar cells on both n-type and p-type wafers, featuring front-side Al metallization and rear-side Cu metallization on polysilicon passivated contacts. The average implied open-circuit voltage for both n-type and p-type unmetallized poly-Si passivating contact solar cell precursors approached around 735 mV after firing, indicating excellent passivation quality. The highest efficiencies achieved so far were 21.8% on the Ag-free front junction n-TOPCon cells and 21.3% for the back junction POLO solar cell with the help of the laser-enhanced contact optimization process.
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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.