Exceptional Optical Absorption of Buckled Arsenene Covering a Broad Spectral Range by Molecular Doping

Abstract

Using density functional theory calculations, we demonstrate that the electronic and optical properties of a buckled arsenene monolayer can be tuned by molecular doping. Effective p-type doping of arsenene can be realized by adsorption of tetracyanoethylene and tetracyanoquinodimethane (TCNQ) molecules, while n-doped arsenene can be obtained by adsorption of tetrathiafulvalene molecules. Moreover, owing to the charge redistribution, a dipole moment is formed between each organic molecule and arsenene, and this dipole moment can significantly tune the work function of arsenene to values within a wide range of 3.99–5.57 eV. Adsorption of TCNQ molecules on pristine arsenene can significantly improve the latter’s optical absorption in a broad (visible to near-infrared) spectral range. According to the AM 1.5 solar spectrum, two-fold enhancement is attained in the efficiency of solar-energy utilization, which can lead to great opportunities for the use of TCNQ–arsenene in renewable energy. Our work clearly demonstrates the key role of molecular doping in the application of arsenene in electronic and optoelectronic components, renewable energy, and laser protection.

Strain engineering on the electronic states of two-dimensional GaN/graphene heterostructure

“…Two-dimensional (2D) materials have received considerable attention owing to their extraordinary electronic, optical, mechanical, chemical, and thermal properties, which make these materials promising for next-generation optoelectronic and nanoelectronic devices. [1][2][3][4][5][6][7] More recently, the main research focus has shied from monocomponent systems to hybrid ones composed of at least two types of chemically different 2D materials, such as graphene/hexagonal boron nitride (h-BN), 8 graphene/black phosphorene (BP), 9 and graphene/transition metal dichalcogenides (TMDs), 10 for the van der Waals (vdW) heterostructure formed between participating materials. This strategy could not only overcome the lattice mismatch-induced defects in participating materials synthesized by epitaxial growth but can also induce excellent physical properties, [11][12][13][14][15][16] thus leading to some very intriguing phenomena such Hofstadter's buttery spectrum, 17,18 strongly bound excitons, 19,20 and spin valley polarization.…”

Noncovalent Functionalization of Pnictogen Surfaces: From Small Molecules to 2D Heterostructures

“…Doping SL or double‐layer (DL) pnictogen surfaces with organic molecules has been investigated using first‐principle calculations . It is evident from Table 5 that TCNQ and tetrathiafulvalene (TTF; Table g) have been extensively investigated through DFT computations .…”

“…Doping SL or double‐layer (DL) pnictogen surfaces with organic molecules has been investigated using first‐principle calculations . It is evident from Table 5 that TCNQ and tetrathiafulvalene (TTF; Table g) have been extensively investigated through DFT computations . Apart from the aforementioned doping agents, other organic molecules include PTCDA for phosphorene, tetracyanoethylene (TCNE; Table h) for phosphorene and arsenene, PDI for antimonene, and tetrafluorotetracyanoquinodimethane (F4‐TCNQ; Table i) and benzyl viologen (BV; Table j) for all of them …”

“…The electrophilic molecules of PTCDA, TCNQ, TCNE, and 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4‐TCNQ) are adsorbed on the surface as electron acceptors while nucleophilic molecules such as TTF, PDI, and BV are adsorbed as electron donors . After adsorption of dopant molecules (acceptors or donors), the bandgap decreases due to the extra/new energy levels added by the impurities (dopant molecules).…”

“…The small bandgap means that lower activation energy is needed for the localized holes (electrons) at new levels to become charge carriers . The dopant molecules including TCNQ, TCNE, and F4‐TCNQ adsorbed on the pnictogen surfaces led to a p‐type conductivity . This was a result of a considerable charge transfer from the pnictogen surface to the TCNQ, TCNE, and F4‐TCNQ molecules.…”