Issue 18, 2019

Amine additive reactions induced by the soft Lewis acidity of Pb2+ in halide perovskites. Part I: evidence for Pb–alkylamide formation

Abstract

Metal halide perovskite materials (ABX3) employed in optoelectronic devices have rapidly achieved high efficiencies. Their performance can be partially attributed to intrinsic defects being electronically benign. Despite the inertness of defects within the bulk, such as ion vacancies, solution processing additives and surface passivation have been shown to enhance material properties. Thus, detailed knowledge of additive chemistry is desirous to elucidate passivation mechanisms and facilitate further improvements. In particular, the soft Lewis acid nature of Pb2+ has been overlooked heretofore as a key feature of amine-lead chemistry in perovskite preparations. In Part I of this study, we demonstrate that acid–base reactions between PbI2 and aliphatic amines yield alkylammonium and Pb–alkylamide species. The alkylammonium and alkylamide products are capable of occupying A-site cation and anion vacancies, respectively. Subsequent incorporation of these impurities at perovskite crystal surfaces or formation of non-perovskite phase inclusions likely influence the perovskite layer morphology and properties which are investigated in Part II. These results reveal a new mechanism by which optoelectronic properties of perovskites can be chemically modified. Additionally, the general concept of acidification of organic molecules solvated to Pb2+ promoting unexpected reactions is applied to explain amine reactions with other additives, such as formic acid. Understanding acid–base reactions induced by PbI2 complexing to protic molecules is useful to comprehend and predict defect/impurity chemistry in a wide variety of perovskite precursor formulations.

Graphical abstract: Amine additive reactions induced by the soft Lewis acidity of Pb2+ in halide perovskites. Part I: evidence for Pb–alkylamide formation

Supplementary files

Article information

Article type
Paper
Submitted
26 सितम्बर 2018
Accepted
15 नवम्बर 2018
First published
15 नवम्बर 2018

J. Mater. Chem. C, 2019,7, 5251-5259

Author version available

Amine additive reactions induced by the soft Lewis acidity of Pb2+ in halide perovskites. Part I: evidence for Pb–alkylamide formation

R. A. Kerner, T. H. Schloemer, P. Schulz, J. J. Berry, J. Schwartz, A. Sellinger and B. P. Rand, J. Mater. Chem. C, 2019, 7, 5251 DOI: 10.1039/C8TC04871A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements