Stability study in lead-halide perovskite light-emitting diodes
type: CreativeWork
description: The metal halide perovskite group of materials not only have led to great advances in photovoltaics, but also have shown great potential in light emitting applications. Other than energy efficiency and brightness, perovskite emitters have advantages such as high colour saturation and low processing temperatures to compete with present inorganic and organic light emitting diode (LED) technologies. However, poor device stability continues to be the limiting factor for perovskite LEDs (PeLEDs) to be realised towards commercialisa- tion. In this thesis, the stability study was first demonstrated on methylammonium lead bromide (MAPbBr3) PeLED device under continuous operations. It was characterised in the post-biased device that the applied electric field simultaneously induces the chemical decomposition of MAPbBr3 material and the dissociation of the active Ag metal electrode. The formation of silver bromide (AgBr) marks the electrochemical degradation of MAPbBr3 and the corrosion of Ag electrode. These factors explain the short lifetime, irreversible device performance and poor emission stability during device operation. It is worth mentioning that emission stability (i.e. colour shifting) remains an unsolved problem in mixed-halide perovskites, as phase segregation problem occurs when external optical/electrical energy exceeds the threshold for halide demixing. In the following part of this thesis, vapour-assist crystallisation (VAC) technique was developed to stabilise the bromide/chloride (Br/Cl) mixed-halide phase and give spectrally stable emission. It was dis- covered that VAC-treatment slows-down the crystallisation process and promotes a two-step halide redistribution within the perovskite thin-film. The controlled crystallisation results in a mixed-halide phase with lower defects and homogeneously ordered composition. Spectrally stable emission was achieved when segregation threshold is raised well-above the maximum working condition of PeLED device. As a resu…
abstract: The metal halide perovskite group of materials not only have led to great advances in photovoltaics, but also have shown great potential in light emitting applications. Other than energy efficiency and brightness, perovskite emitters have advantages such as high colour saturation and low processing temperatures to compete with present inorganic and organic light emitting diode (LED) technologies. However, poor device stability continues to be the limiting factor for perovskite LEDs (PeLEDs) to be realised towards commercialisa- tion. In this thesis, the stability study was first demonstrated on methylammonium lead bromide (MAPbBr3) PeLED device under continuous operations. It was characterised in the post-biased device that the applied electric field simultaneously induces the chemical decomposition of MAPbBr3 material and the dissociation of the active Ag metal electrode. The formation of silver bromide (AgBr) marks the electrochemical degradation of MAPbBr3 and the corrosion of Ag electrode. These factors explain the short lifetime, irreversible device performance and poor emission stability during device operation. It is worth mentioning that emission stability (i.e. colour shifting) remains an unsolved problem in mixed-halide perovskites, as phase segregation problem occurs when external optical/electrical energy exceeds the threshold for halide demixing. In the following part of this thesis, vapour-assist crystallisation (VAC) technique was developed to stabilise the bromide/chloride (Br/Cl) mixed-halide phase and give spectrally stable emission. It was dis- covered that VAC-treatment slows-down the crystallisation process and promotes a two-step halide redistribution within the perovskite thin-film. The controlled crystallisation results in a mixed-halide phase with lower defects and homogeneously ordered composition. Spectrally stable emission was achieved when segregation threshold is raised well-above the maximum working condition of PeLED device. As a resu…
author: Yi, Ziyue
language: eng
keywords: Perovskite, Light-emitting diode, mixed-halide perovskite
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/61d27412-d0d3-439e-bc88-c1d76a85801e/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2021-01-01
date modified: 2026-07-22T22:24:21Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.73565