The phase state and Far-IR spectroscopy study of ZnS: Mn synthesized by malic acid-assisted hydrothermal method

• 1、College of Chemistry & Chemical Engineering, Anhui University,Hefei, 230039
• 2、(College of Chemistry & Chemical Engineering, Anhui University,Hefei, 230039)

Abstract： ZnS:Mn microcrystals were synthesized by a malic acid-assisted hydrothermal method in this paper. The amount of the complexing agent -malic acid played a key role in the crystal nucleation and growth. The phase of the ZnS:Mn was transited from the mixed to the cubic one as the amount of malic acid increased from 0 g to 2 g, accompanied with the morphology becoming more regular. The complexes of malic acid with Zn2+ and Mn2+ ions controlled the releasing rate of metal ions in the reaction system effectively and regulated the growth rate of ZnS:Mn microcrystals. The lattice vibration of the ZnS:Mn were studied by using far infrared (Far-IR) spectroscopy and Raman spectroscopy. The results revealed that one absorption peak of ZnS in the range of 350 ~ 200 cm-1 split into two peaks as for ZnS:Mn, which locating at 279 and 315 cm-1, respectively. This split of the peak was probably because of the doped Mn2+ ions both incorporated into the lattice and located in the point defects sites, which made the absorption intensity of TO vibration mode decreased at 279 cm-1 and while enhanced at 315 cm-1. In addition, the absorption peak at 414 cm-1 in Far-IR spectra became weaker due to the better crystallinity and thus the reduced crystallographic defects with increasing amount of malic acid during the synthesis.

Keywords： ZnS: Mn malic acid phase transition far-infrared