Alloy Engineering in Few-Layer Manganese Phosphorus Trichalcogenides for Surface-Enhanced Raman Scattering

Manganese phosphorus trichalcogenides are widely used in the field of photocatalysis and magnetic studies due to their broadband gaps. Herein, an alloy engineering method for the few-layer manganese phosphorus trichalcogenides (MnPS3-xSex, 0 <= x <= 3) in surface-enhanced Raman scattering (SERS) is reported. A new strategy, with the coupling of exciton resonance (mu(ex)) and photoinduced charge transfer (PICT), is applied to screen out materials for SERS enhancement. According to the calculation of density functional theory, the bandgap of manganese phosphorus trichalcogenides (MnPS3) can be adjusted to match the band energy of Rhodamine 6G molecules by alloy engineering. Furthermore, a series of few-layer MnPS3-xSex (0 <= x <= 3) are fabricated to study the PICT-induced SERS behavior under resonance excitation. The good performance with a detection limit down to 10(-9) m indicates that the synergistic resonances between mu(ex) and PICT are crucial to the enhancement.