Campus Units

Chemical and Biological Engineering, Ames Laboratory

Document Type

Article

Research Focus Area

Advanced and Nanostructured Materials

Publication Version

Submitted Manuscript

Publication Date

6-5-2019

Journal or Book Title

Chemistry of Materials

DOI

10.1021/acs.chemmater.9b00238

Abstract

Assembling halide perovskites into layered structures holds promise for addressing chemical and phase stability challenges; however, several other challenges need to be addressed to create efficient and stable halide perovskite devices. Layered halide perovskites (LHPs) suffer from broad distribution of layer thicknesses and bandgaps within thin films. Reducing polydispersity could substantially improve charge transport within LHP films and the performance of LHP-based solar cells. Herein, we focused on layering α-CsPbI3 ((C4H9NH3)2Csn-1PbnI3n+1) thin films. We found that (C4H9NH3)2Csn-1PbnI3n+1 with nominal layer thicknesses of n = 1, 2, 3, and 4 can be deposited at temperatures as low as 100 °C, substantially below the phase transition temperature of bulk α-CsPbI3. Furthermore, we demonstrated that incorporating highly complexing solvents into the precursor solution promotes the formation of intermediate phases within the thin film, slowing down LHP crystallite nucleation, eventually resulting in improved phase purity. Reducing decomposition rates through combined use of solvent complexes and thermal processing methods, we fabricated (C4H9NH3)2CsPb2I7 films that had improved phase purity, crystallinity, and film morphology. We also demonstrate that the photoluminescence had a maximum intensity corresponding to the targeted n = 2 phase. This work represents a step towards highly stable LHP thin films with narrow site-energy distribution.

Comments

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Chemistry of Materials, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acs.chemmater.9b00238. Posted with permission.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

Published Version

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