Growth modes and quantum confinement in ultrathin vapour-deposited MAPbI₃ films

Abstract

We examine the initial growth modes of MAPbI3 films deposited by co-evaporation, with average thicknesses from 2–320 nm. Electronic quantum confinement effects are observed for films with average thickness below 40 nm.

Investigating the Tetragonal‐to‐Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

“…An alternative interpretation of the blue‐shift is via a quantum confinement effect, where the decreasing domain size confines the excited state, leading to a blue‐shift of the PL. [ 55 ] The observed blue‐shift of 20 meV implies domain sizes of 7–15 nm, based on the correlation between PL peak position and crystal size of MAPbI 3 nanocrystals found in literature, [ 56–58 ] and on the assumption that this correlation also applies to the tetragonal inclusions. We estimate the domain volume to be about (15 nm) 3 , consider that 0.001% of the crystal is in the tetragonal phase (as it is the case at 145 K) and we assume that the tetragonal inclusions are distributed homogeneously.…”

CsPbBr3 Nanocrystal Films: Deviations from Bulk Vibrational and Optoelectronic Properties

“…The low dimensionality and the high surface‐to‐volume ratio of semiconductor NCs have been shown to have an effect on their crystal lattice. [ 15–17 ] To investigate such effects, we examined the structural properties of the bulk and nanocrystalline perovskite films by X‐ray diffraction (XRD). The diffraction patterns obtained for the polycrystalline CsPbBr 3 and 10 nm NCs deposited on quartz are shown in Figure 1b (see Figure S7, Supporting Information, for complete diffraction data for all NC sizes).…”

Light Absorption and Recycling in Hybrid Metal Halide Perovskite Photovoltaic Devices

“…While sequentially evaporating the perovskite precursors has yielded films of respectable quality, it has disadvantages, the main being the requirement of an annealing step for thorough mixing of the precursors. Alternatively, coevaporation does not require any annealing step, expanding the number of substrates upon which the film can be deposited, as well as allowing finer control over the thickness of the film . One disadvantage of coevaporation over the sequential deposition method is that controlling and optimizing the deposition rate of each precursor simultaneously is not trivial .…”

“…Alternatively, coevaporation does not require any annealing step, expanding the number of substrates upon which the film can be deposited, as well as allowing finer control over the thickness of the film. [37,38,43] One disadvantage of coevaporation over the sequential deposition method is that controlling and optimizing the deposition rate of each precursor simultaneously is not trivial. [44] However, once the deposition rate of each precursor is optimized, the resultant films consist of a high-quality perovskite.…”