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The Origin of Broad Emission in ⟨100⟩ Two-Dimensional Perovskites: Extrinsic vs Intrinsic Processes.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Meggiolaro, Daniele  ORCID logo  https://orcid.org/0000-0001-9717-133X
Gregori, Luca 
Tekelenburg, Eelco K  ORCID logo  https://orcid.org/0000-0001-8962-5434
Pitaro, Matteo 

Abstract

2D metal halide perovskites can show narrow and broad emission bands (BEs), and the latter's origin is hotly debated. A widespread opinion assigns BEs to the recombination of intrinsic self-trapped excitons (STEs), whereas recent studies indicate they can have an extrinsic defect-related origin. Here, we carry out a combined experimental-computational study into the microscopic origin of BEs for a series of prototypical phenylethylammonium-based 2D perovskites, comprising different metals (Pb, Sn) and halides (I, Br, Cl). Photoluminescence spectroscopy reveals that all of the compounds exhibit BEs. Where not observable at room temperature, the BE signature emerges upon cooling. By means of DFT calculations, we demonstrate that emission from halide vacancies is compatible with the experimentally observed features. Emission from STEs may only contribute to the BE in the wide-band-gap Br- and Cl-based compounds. Our work paves the way toward a complete understanding of broad emission bands in halide perovskites that will facilitate the fabrication of efficient narrow and white light emitting devices.

Description

Keywords

34 Chemical Sciences, 3406 Physical Chemistry

Journal Title

ACS Energy Lett

Conference Name

Journal ISSN

2380-8195
2380-8195

Volume Title

7

Publisher

American Chemical Society (ACS)
Sponsorship
Dutch Research Council (739.017.005)