Optical and Photocatalytic Properties of ZnS:Mn Nanocrystals

Abstract

The colloidal ZnS:Mn nanoparticles were obtained by using thermochemical method with the reaction duration varied from 1 h to 7 h. The bandgap of the ZnS:Mn nanocrystals increases from 3.75 eV to 4.06 eV with decreasing particle size from 5.8 nm to 2.4 nm, respectively. At room temperature, the ZnS:Mn nanoparticles exhibit orangered emission due to the 4 T1(4 G) → 6 A1(6 S) transition within the 3d 5 configuration of Mn 2+ ions inside the ZnS host. The orange-red photoluminescence can be excited at energies corresponding to the Mn 2+ ion own excited states. The 6 A1(6 S)→ 4 E2(4 P); 6 A1(6 S)→ 4 T2(4 P); 6 A1(6 S)→ 4 E(4 G), 4 A1(4 G); 6 A1(6 S)→ 4 T2(4 G), and 6 A1(6 S)→ 4 T1(4 G) absorption transitions have been observed in the photoluminescence excitation spectra. Photocatalytic properties of the samples have been investigated via absorption spectra of methyl orange (MO) in present of ZnS:Mn nanoparticles. The photo-degradation of MO obeys the pseudo-first-order kinetics law. The reaction rate constant k for MO degradation was 0.0065 min −1 .

First‐principles Calculations Reveal Frictional Advantage for C2N/C6N6 van der Waals Heterostructures

“…In order to treat the exchange correlation functional, Perdew‐Burke‐Ernzerhof (PBE) within a generalized gradient approximation (GGA) has been taken into account. The two different structures of polymeric carbon nitride family, namely, C 2 N and C 6 N 6 have been taken for their versatile applications in various fields [23–26] . The computational cell of heterostructure is composed of 2×2 supercell of C 6 N 6 and $${\sqrt{3}\times \sqrt{3}}$$ supercell of C 2 N with 20 Å vacuum along Z‐direction to avoid the interaction between periodic images.…”