Electronic Structure Modification of Rectangular Phosphorene Quantum Dots Via Edge Passivation

• Published in: Journal of physical chemistry. C Vol. 125; no. 9; pp. 5029 - 5036
• Main Authors: De Alwis, W. M. Uvin G, Weerawardene, K. L. Dimuthu M, Ellington, Thomas L, Shuford, Kevin L
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11-03-2021
• Subjects: C: Chemical and Catalytic Reactivity at Interfaces; Electrical conductivity; Functional groups; Functionalization; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Monolayers; Two dimensional materials
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.0c09722

Phosphorene is an elemental two-dimensional material that shows great promise as a metal-free photocatalyst owing to its high carrier mobility and direct band gap. Doping and edge functionalization of phosphorene can be exploited to tune its band gap and alter other properties. Herein, the electronic properties of a series of edge-passivated monolayer phosphorene quantum dots are investigated using an array of functional groups (OH, SH, NH2, SCH3, OCN, CN, and Cl) that are known to have electron-donating or electron-withdrawing capabilities. By employing density functional theory calculations, we demonstrate that edge functionalization can perturbatively shift the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels while simultaneously preserving the geometric structure and other favorable properties of pristine phosphorene. We use the average overall electrostatic potential of these systems to successfully predict the relative positioning of the HOMO and LUMO energy levels while presenting qualitative explanations on potential jumps introduced by the dipole layers formed due to edge functionalization. Our results suggest that selective functionalization permits considerable control over the band edge positions, which could be utilized for applications in energy and optoelectronic devices.