Influence of additives on the in situ crystallization dynamics of methyl ammonium lead halide perovskites

DOI: 10.1021/acsaem.0c02625

Authors: Edwin Pineda De La O (The University of Sheffield) , Noura Alhazmi (The University of Sheffield) , Stephen J. Ebbens (The University of Sheffield,) , Alan D. F. Dunbar (The University of Sheffield)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Energy Materials , VOL 3

State: Published (Approved)
Published: February 2021
Diamond Proposal Number(s): 20757

Abstract: Understanding the kinetics of the crystallization process for organometal halide perovskite formation is critical in determining the crystalline, nanoscale morphology and therefore the electronic properties of the films produced during thin film formation from solution. In this work, in situ grazing incidence small-angle X-ray scattering (GISAXS) and optical microscopy measurements are used to investigate the processes of nucleation and growth of pristine mixed halide perovskite (MAPbI3–xClx) crystalline films deposited by bar coating at 60 °C, with and without additives in the solution. A small amount of 1,8-diiodooctane (DIO) and hydriodic acid (HI) added to MAPbI3–xClx is shown to increase the numbers of nucleation centers promoting heterogeneous nucleation and accelerate and modify the size of nuclei during nucleation and growth. A generalized formation mechanism is derived from the overlapping parameters obtained from real-time GISAXS and optical microscopy, which revealed that during nucleation, perovskite precursors cluster before becoming the nuclei that function as elemental units for subsequent formation of perovskite crystals. Additive-free MAPbI3–xClx follows reaction-controlled growth, in contrast with when DIO and HI are present, and it is highly possible that the growth then follows a hindered diffusion-controlled mechanism. These results provide important details of the crystallization mechanisms occurring and will help to develop greater control over perovskite films produced.

Journal Keywords: perovskite; small-angle X-ray scattering; optical microscopy; crystallization; bar coating; dynamics

Diamond Keywords: Photovoltaics; Semiconductors

Subject Areas: Materials, Chemistry, Energy


Instruments: I22-Small angle scattering & Diffraction

Added On: 08/02/2021 09:33

Documents:
acsaem.0c02625.pdf

Discipline Tags:

Surfaces Earth Sciences & Environment Sustainable Energy Systems Energy Physics Climate Change Energy Materials Chemistry Materials Science Chemical Engineering interfaces and thin films Engineering & Technology Inorganic Chemistry Perovskites Metallurgy

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS) Grazing Incidence Small Angle Scattering (GISAXS)