Presentation Details
| Impact of solvent engineering on improving perovskite performance in a scalable two-step hybrid deposition process Raju Pusapati1, 2, 3, Sunil Suresh1, 2, 3, Aslihan Babayigit1, 2, 3, Sanjay Sandhu4, Cristian Villalobos Meza2, 3, Tamara Merckx2, 3, Jef Poortmans1, 2, 3, Tom Aernouts2, 3, Jessica de Wild2, 3, Bart Vermang1, 2, 3. 1IMO-IMOMEC, University of Hasselt, Diepenbeek, Belgium.2Energy Ville, Genk, Belgium.3IMEC, Genk, Belgium.4University of Strathclyde, Glasgow, United Kingdom |
Abstract
Two-step perovskite deposition has attracted significant interest due to its compatibility with textured substrates. However, implementing a scalable hybrid process combining inorganic-layer co-evaporation with blade coating remains challenging, as solvent limitations during the second-step conversion often restrict perovskite crystallisation, film uniformity, and device performance. While many studies attribute these limitations primarily to the high vapour pressure of alcohol-based solvents, such approaches overlook the critical role of solvent–precursor coordination in governing crystallisation kinetics. Here, we demonstrate a solvent coordination engineering strategy for 1.68 eV wide-bandgap perovskite absorbers fabricated via a vacuum/solution hybrid two-step process while deliberately retaining highly volatile alcohol-based solvents. By optimising the inorganic layer to minimise residual PbI₂ and introducing a Lewis base coordinating additive (N-methyl-2-pyrrolidone, NMP) into an IPA-based second-step solvent, controlled perovskite formation is achieved without relying on low-volatility or high–boiling-point solvents. Enhanced coordination between NMP and precursor salts moderates nucleation and crystal growth, lowering the energy barrier for crystallisation and improving absorber morphology, crystallinity, uniformity, and optoelectronic properties. As a result, the open-circuit voltage increases from 1.08 V to 1.09 V and the fill factor from 75% to 80.5% without surface passivation. With HTL interface passivation, a champion efficiency of 20.7% and a fill factor of 82.3% highest achieved for a bandgap of 1.68eV through scalable two-step hybrid deposition methods on an active area of 0.125cm2. These results establish precursor coordination, rather than solvent vapour pressure alone, as a key design parameter for scalable hybrid perovskite deposition, enabling high-quality wide-bandgap absorbers suitable for tandem solar cell 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.