Abstract
ZnSe nanoparticles (NPs) were prepared by combining both hydrothermal and mechanical milling methods. Transmission electron microscopy images show that fabricated ZnSe NPs with a sphere-like shape have an average size (d) in the range of 20–100 nm, affected by changing the milling time from 10 to 60 min. All the samples crystalize in zincblende-type structure without impurities, as confirmed by analyzing X-ray diffraction patterns, Raman spectra, and energy-dispersive X-ray spectroscopy. Carefully checking Raman spectra, we have observed the broadening and redshift of vibration modes as decreasing NP size, which are ascribed to extra appearance of disorder and defects. The photoluminescence study has found a blue emission at 462 nm attributed to the excitonic near-band edge and a broad defect-related emission around 520–555 nm. Increasing milling time leads to the decrease in the exciton-emission intensity, while the defect-related emissions increase gradually. Interestingly, as decreasing d, we have observed an improved photodegradation of Rhodamine B under UV irradiation, proving application potentials of ZnSe NPs in photocatalytic activity.
Highlights
Zi-An Li and Jimin WangIn recent years, nanostructured semiconductors have been widely studied for understanding their fundamental properties and for technological applications in electronic and optoelectronic devices [1,2]
The zincblende-type structure of ZnSe is depicted in Figure 3a for illustration
We investigate the structural characterization, optical properties, and photocatalytic performance of ZnSe NPs, which were obtained by changing the milling time tm = 0–60 min
Summary
In recent years, nanostructured semiconductors have been widely studied for understanding their fundamental properties and for technological applications in electronic and optoelectronic devices [1,2] They have great potential in the photocatalysis for solar-fuel production and environmental remediation [3]. It has been found that ZnSe is an excellent candidate because it is known as a suitable band gap (Eg = 2.67 eV) material [5] and has a large exciton binding energy at room temperature (21 meV), which can be used as a photocatalyst in degrading pollutant molecules, including methylene blue [6], Rhodamine B (RhB) [7], and methyl orange [8,9]. Suitable values of Eg and exciton binding energy of ZnSe are important criteria to fabricate blue-laser diodes and blue-emitting diodes [10,11]
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