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.

中文翻译：

---

调节碲化锰量子点 (MnTe QD) 的带隙以实现光催化

溶液中激光烧蚀合成（LASiS）用于合成碲化锰（MnTe）量子点（QD）。尺寸可调的量子点在带隙、光学、电学和磁学性质方面表现出物理化学性质的变化。量子点的尺寸通过激光烧蚀的不同功率和持续时间进行微调。使用基本结构和形态表征研究了 MnTe 量子点的特性。正如 DFT 模拟所预测的那样，材料中观察到的带隙开口是由于量子限制效应导致的能带分离增加。合成的MnTe QD催化剂的磁性影响降解过程，该过程遵循伪一级动力学。使用紫外-可见光谱研究光催化染料降解。在外部磁场下，MnTe QD 能够在 60 分钟内光降解亚甲基蓝试剂高达 93.4%。与仅暴露在阳光下 (0.00456 min ^-1 )相比，磁场诱导的 MnTe QD 显示出增强的光催化降解效率，表观速率动力学提高了十倍 (0.0453 min ^-1 ) 。

图形概要

(a) 合成分散的 MnTe QD 的 HAADF-STEM，(b) 相同的 SEM 图像，(c) 有和没有磁场的样品的相对浓度，插图：磁场暴露下的光降解样品，(d)光催化染料降解的示意图。