Molecular intercalation in black phosphorus with tunable bandgaps for infrared photoelectric materials

Abstract

Bulk and monolayer black phosphorus have narrow and wide fundamental bandgaps, respectively, in the middle- and short-wavelength infrared regions. In order to tune the bandgap energy between those two materials continuously, we introduce a tunable quantum confinement effect and propose a new mechanism for the organic–inorganic hybrid superlattice, which is a sandwich-like structure via organic molecules intercalating into bulk black phosphorus. By combining both molecular dynamics simulations and density functional theory calculations, we reveal the stacking morphology and optical properties of the hybrid superlattice, and both the interlayer distance (1.07 nm) and absorption bandgap (1.78 eV) show good agreement with experimental measurements. The superlattice has a continuously tunable absorption bandgap from 0.30 eV to 1.78 eV, following the organic molecule density increasing from 0 cm⁻³ to 6.1 × 10²⁰ cm⁻³. Considering these continuously tunable infrared properties, it could be a promising candidate with wide applications in the field of infrared photoelectric materials.