Anisotropic Behavior of Optical Properties in Edge-Modified Phosphorene Quantum Dots
Anisotropic Behavior of Optical Properties in Edge-Modified Phosphorene Quantum Dots
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DOI：
10.1021/acs.jpcc.3c01463
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发表时间：
2023-06
期刊：
影响因子：
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通讯作者：
W. D. De Alwis;K. Shuford
中科院分区：
文献类型：
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作者：
W. D. De Alwis;K. Shuford
低维磷烯量子点的光学性质的演变仍然是一个很大程度上未被探索的领域，在光电器件方面具有巨大的应用潜力。在此，我们利用密度泛函理论和瞬态密度泛函理论计算对边缘钝化（H、NH2、Cl、OCN、CN）单层磷烯量子点的光学性质进行了全面分析。对吸收、非辐射弛豫、辐射发射、辐射寿命和高频拉曼模式（Ag1、B2g 和 Ag2）进行了广泛的表征，强调了材料方向性、量子限制和边缘钝化对这些特性演变的作用。我们的结果表明，无论边缘功能化的类型或系统尺寸如何，光学吸收和发射都优先从磷烯的扶手椅方向进行，使这些系统成为紫外可见区域中潜在的天然线性光学偏振器。较大的磷烯量子点具有较小的斯托克斯位移和弛豫时较小的几何变化，从而导致辐射寿命缩短。此外，我们还发现了与银峰的不同移动趋势相关的非典型拉曼响应，这些变化趋势是由磷烯量子点在扶手椅或之字形方向的平面生长引起的。该行为归因于质量耦合和粘合强度提高的竞争效应。
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, NH2, 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 (Ag1,B2g, andAg2) 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 theAgpeaks 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.