Symmetry effect on the mechanism of the optical absorption of phosphorene quantum dots

Jiang, Zhaotan; Liang, Feixia; Lv, Zengtao; Ren, Yuehong; Han, Qi

doi:10.1016/j.physe.2018.11.005

Cited by 3 publications

(1 citation statement)

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“…However, when passivated at the edges, these armchair nanoribbons transform into direct band-gap semiconductors. As a result, the first peak in the absorption spectra is optically active, corresponding to transitions from the valence band to conduction band, as opposed to zigzag nanoribbons that are known to have dark symmetry gaps with active higher-energy transitions. , Preferential absorption of light polarized along the armchair direction has been reported in certain phosphorene quantum dots (PQDs) using tight-binding methods. − These quantum dot systems typically possess fundamental band gaps and optical gaps that are largely governed by quantum confinement. Emission gaps for certain PQDs have been shown to have more complex trends due to competing relaxation effects …”

Section: Introductionmentioning

confidence: 99%

Anisotropic Behavior of Optical Properties in Edge-Modified Phosphorene Quantum Dots

Alwis

Shuford

2023

J. Phys. Chem. C

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The evolution of optical properties in low-dimensional phosphorene quantum dots remains a largely unexplored area, with great potential for applications as optoelectronic devices. Herein, we present a comprehensive analysis of the optical properties of edge-passivated (H, NH 2 , Cl, OCN, CN) monolayer phosphorene quantum dots using density functional theory and time-dependent density functional theory calculations. An extensive characterization of absorptions, nonradiative relaxations, radiative emissions, radiative lifetimes, and the high-frequency Raman modes (A g 1 , B 2g , and A g 2) is undertaken, emphasizing the role of material directionality, quantum confinement, and edge passivation on the evolution of these properties. Our results indicate that optical absorptions and emissions are preferred from the armchair direction of phosphorene regardless of the type of edge functionalization or system size, rendering these systems as potential natural linear optical polarizers in the UV−vis region. Larger phosphorene quantum dots have smaller Stokes shifts and less geometric variation upon relaxation, leading to decreased radiative lifetimes. Additionally, we identify an uncharacteristic Raman response associated with dissimilar shifting trends of the A g peaks that arise from the planar growth of phosphorene quantum dots in the armchair or the zigzag direction. The behavior is attributed to the competing effects of mass coupling and improved bond strength.

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