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

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.