Presentation Details
| High-frequency Ultrasound Assisted Defect Healing in Halide Perovskite Thin Films Arkita Chakrabarti1, Farzaneh Rezaei1, Kelly Vences2, Yuxi Zhang3, Connor Dolan2, Niranjana Mohan Kumar1, Nasim Alem3, David Fenning2, Mariana Bertoni1. 1Arizona State University, Tempe, AZ, USA.2University of California San Diego, La Jolla, CA, USA.3Pennsylvania State University, State College, PA, USA |
Abstract
Conventional processing techniques can introduce performance-limiting extended defects in halide perovskite thin films, such as dislocations, twins and stacking faults, that reside in the bulk and are inaccessible to chemical-based surface passivation. In this work, we demonstrate the use of high-power acoustic energy as a facile, chemical-free strategy to improve the bulk crystal quality of formamidinium lead iodide (α-FAPbIā) thin films. Ultrasound has been known to promote recovery in metals, with the underlying mechanism attributed to acoustically induced activation of dislocation motion followed by dislocation annihilation. We hypothesize, that halide perovskites, which exhibit metal-like plasticity, will undergo similar defect dynamics when subjected to acoustic treatment (insonation), leading to dislocation motion and annihilation and ultimately a reduced dislocation density within the lattice. Consistent with this hypothesis, insonated thin films exhibit higher perovskite phase purity and a significant reduction in lattice disorder and strain. These structural changes translate to enhanced optoelectronic properties such as a boost in PLQY and improved device metrics.
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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.