Presentation Details
| Towards Compatible Encapsulants for Industrial Perovskite-Silicon Tandem Modules Chiara Barretta1, Petra Christoefl1, Marcel Kuehne2, Markus Franke2, Frans Op den Buijsch3, Roland Milatz3, Lisa Champault4, Quentin Jeangros4, Quiterie Emery5, Mark Khenkin5, Carolin Ulbrich5, Gernot Oreski1, 6. 1Polymer Competence Center Leoben GmbH (PCCL), Leoben, Austria.2Hanwha Q CELLS GmbH, Bitterfeld-Wolfen, Germany.3The Compound Company, Enschede, Netherlands.4Swiss Center for Electronics and Microtechnology (CSEM), Neuchatel, Switzerland.5Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany.6Technical University of Leoben, Leoben, Austria |
Abstract
Perovskite-silicon tandem photovoltaic (PV) modules impose tighter thermal and mechanical constraints than conventional c-Si modules, making encapsulation a critical bottleneck for industrial upscaling. Industrial lamination temperatures near 150 °C, acceptable for c-Si, exceed the thermal stability window of perovskites, and the multilayer tandem stack introduces interfaces sensitive to thermo-mechanical strain, delamination, and moisture ingress. Despite rapid progress in device efficiencies, encapsulation materials have so far not been developed for tandems, and the criteria governing low-temperature lamination and long-term reliability remain insufficiently defined. In this work, twenty-two mainly commercial encapsulation films were assessed for tandem-relevant processing and operation. Materials were characterized for chemical composition, crosslinking behavior, thermo-mechanical and dimensional stability, and optical performance, and were comparatively ranked using an attribute-based scoring methodology. Thermo-mechanical behavior emerged as the dominant discriminator. Several crosslinking polyolefin films showed favorable melting temperatures and viscosity windows for low-temperature lamination, whereas thermoplastic polyurethane films exhibited high viscosity and limited flow, increasing mechanical loading on the perovskite stack. Crosslinking onset for peroxide-initiated systems remained relatively high for tandem integration and should be shifted downward. Dimensional stability, captured through anisotropy and total displacement during heating, proved equally important: materials with high residual stresses risk inducing strain and interfacial failure in the tandem stack during lamination. Optical transparency was generally adequate (>90 % solar-weighted transmittance), and therefore not the limiting factor for material selection, although interactions between additives and perovskites require further investigation. No single commercial material fulfilled all tandem-specific criteria; however, several candidates with low viscosity, acceptable dimensional stability, and appropriate optical performance were identified. The methodology establishes structured selection criteria and highlights encapsulant properties that must be adapted for tandem industrialization, including reduced crosslinking onset, tailored viscosity in the 100–130 °C range, and minimized anisotropic shrinkage. These specification windows provide guidance for tandem-specific encapsulant development and module integration.
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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.
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