Quantum-confinement effect on the linewidth broadening of metal halide perovskite-based quantum dots. (6th July 2021)

• Record Type: Journal Article
• Authors: Jang, Hyun Myung; Park, Jinwoo; Kim, Sungjin; Lee, Tae-Woo
• Is Part Of: Journal of physics. Volume 33:Number 35(2021)
• Publication Date: 2021-07-06
• Subjects: linewidth broadening -- quantum confinement -- exciton -- metal halide perovskites -- photoluminescence -- light-emitting diodes; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac00db
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The linewidth broadening caused by various physicochemical effects does limit the well-known advantage of ultrahigh color purity of metal halide perovskites (MHPs) for use in next-generation light-emitting diodes (LEDs). We have theoretically examined the quantum- and dielectric-confinement effects of a quantum dot (QD) on the degree of photoluminescence linewidth broadening. It is predicted that the linewidth (Δ λ QC ) is mainly contributed by the two opposing effects: (i) the linewidth broadening due to the repulsive kinetic energy of confined excitons ( Δ λ Q C K E ) and (ii) the overall linewidth narrowing caused by the attractive Coulomb interaction ( Δ λ Q C C o u l ). It is shown that the relative contribution essentially remains at a constant value and is evaluated as Δ λ Q C C o u l / Δ λ Q C K E = 0.42, which is independent of the QD size and the chemical nature of semiconducting emitter. We have computed Δ λ QC for various QD sizes of the prototypical MHP emitter, MAPbBr3, where MA denotes a methylammonium (CH3 NH3 ) organic cation. The calculated results show that the linewidth broadening due to the quantum confinement (Δ λ QC ) increases rapidly beginning at the QD radius approximately equal to 6.5 nm but Δ λ QC is less than 2 nm even at R = 1.5 nm. Thus, Δ λ QC is much narrower than the linewidth caused by the exciton-LO phonon Fröhlich coupling (∼23.4 nm) which is known as the predominant mechanism of linewidth broadening in hybrid MHPs. Thus, the linewidth broadening due to the quantum confinement (Δ λ QC ) is not a risk factor in the realization of MHP-based ultrahigh-quality next-generation LEDs.