Tuning the band gap of manganese telluride quantum dots (MnTe QDs) for photocatalysis

• Published in: Applied physics. A, Materials science & processing Vol. 130; no. 5
• Main Authors: Chowde Gowda, Chinmayee, Chandravanshi, Dharita, Tromer, Raphael M., Malya, Ambreesh, Chattopadhyay, Kamanio, Galvão, Douglas Soares, Tiwary, Chandra Sekhar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2024; Springer Nature B.V
• Subjects: Ablation; Characterization and Evaluation of Materials; Chemical synthesis; Condensed Matter Physics; Dyes; Energy bands; Energy gap; Intermetallic compounds; Kinetics; Laser ablation; Machines; Magnetic fields; Magnetic properties; Manganese; Manufacturing; Methylene blue; Nanotechnology; Optical and Electronic Materials; Optical properties; Photocatalysis; Photodegradation; Physics; Physics and Astronomy; Processes; Quantum confinement; Quantum dots; Reagents; Surfaces and Interfaces; Tellurides; Thin Films; Quantum dots (QDs); Magnetic field induced degradation; Laser ablation in solution; Manganese telluride
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-024-07378-x

Laser ablation synthesis in solution (LASiS) was used to synthesize quantum dots (QDs) of manganese telluride (MnTe). Size-tuneable QDs exhibit physicochemical property variation in the bandgap, optical, electrical, and magnetic properties. The size of QDs was fine-tuned with varying power and time duration of laser ablation. The characteristics of MnTe QDs were investigated using basic structural and morphological characterizations. The observed bandgap opening in the material is due to the quantum confinement effect, which led to increased energy band separation, as predicted from DFT simulations. The magnetic property of the synthesized MnTe QD catalysts influences the degradation process, with the process following pseudo-first-order kinetics. The photocatalytic dye degradation was studied using UV–visible spectroscopy. MnTe QDs were able to photodegrade methylene blue reagent up to 93.4% in 60 min under an external magnetic field. The magnetic field-induced MnTe QDs showed enhanced photocatalytic degradation efficiency with increased apparent rate kinetics up to ten times (0.0453 min
−1
) compared to just sunlight exposure (0.00456 min
−1
).
Graphical Abstract
(a) HAADF-STEM of the synthesized MnTe QD dispersed, (b) SEM image of the same, (c) relative concentration of the samples with and without magnetic fields, inset: photo degraded samples on exposure of magnetic fields and (d) schematic representation of the photocatalytic dye-degradation.