Significantly Enhanced Photoluminescence Performance of Ni_xS_y(NiS and Ni₉S₈)/ZnO Nanorods by a Hydrothermal Method

Abstract

This paper reports on a near zero band gap semiconductor, Ni x S y , which significantly enhances the photoluminescence (PL) performance of ZnO nanorods. The structural, morphological, and optical properties of the composites were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible spectroscopy (UV–vis), PL spectrometry, etc. The PL patterns at an excitation wavelength (λex) of 325 nm revealed that the 10% Ni x S y /ZnO nanorod (10NZNR) composites displayed the highest emission intensity in the region of 420–630 nm. The relationship between the emission intensity of ZnO and the concentration of Ni x S y demonstrated that the PL intensity of NZNRs initially increased (<10%) and then declined with an increase in Ni x S y content (>10%). According to PL spectra at different excitation wavelengths and PL excitation (PLE) spectra, the visible emission of Ni x S y /ZnO nanorod (NZNR) composites can only be excited by light with energy greater than that of the band gap. Studies of the morphological structures and PL behaviors of NZNR composites have illustrated that Ni x S y considerably enhances the visible emission of ZnO by regulating its morphology and structure. An appropriate mechanism by which Ni x S y enhances the PL performance of ZnO has been proposed.

In Situ Construction of ZnO/Ni2S3 Composite on Ni Foam by Combing Potentiostatic Deposition with Cyclic Voltammetric Electrodeposition

“…The S 2p spectrum in Figure 5d can be divided into two peaks that are centered at 162.99 and 161.54 eV, corresponding to S 2p1/2 and S 2p3/2 of S 2− , respectively, which are in agreement with those of Ni2S3 in the reports [23,24]. 5a), two peaks located at 1044.70 and 1021.40 eV belong to Zn 2p 1/2 and Zn 2p 3/2 , respectively, confirming the existence of ZnO [10,18]. As for the Ni 2p spectrum in Figure 5b, two major peaks of the binding energies at 855.60 and 873.30 eV, with a spin-energy separation of 17.7 eV, correspond to Ni 2p 3/2 and Ni 2p 1/2 , respectively, indicating the emergence of Ni 2+ and Ni 3+ [19][20][21].…”

“…Apart from that, both of them have a satellite peak at 861.20 and 879.80 eV [22]. In regard to the O 1s spectrum in Figure 5c, as previously reported, the binding energy of 531.20 eV is ascribed to the oxygen bond with Zn 2+ , and the binding energy of 529.90 eV is assigned to the oxygen of NiO, which was generated from the reduction in part of the Ni 3+ during electrodeposition [10,18]. The S 2p spectrum in Figure 5d can be divided into two peaks that are centered at 162.99 and 161.54 eV, corresponding to S 2p 1/2 and S 2p 3/2 of S 2− , respectively, which are in agreement with those of Ni 2 S 3 in the reports [23,24].…”

“…Figure 5 depicts the survey XPS spectra of the ZnO/Ni 2 S 3 composite. From the Zn 2p spectrum ( Figure 5 a), two peaks located at 1044.70 and 1021.40 eV belong to Zn 2p 1/2 and Zn 2p 3/2 , respectively, confirming the existence of ZnO [ 10 , 18 ]. As for the Ni 2p spectrum in Figure 5 b, two major peaks of the binding energies at 855.60 and 873.30 eV, with a spin-energy separation of 17.7 eV, correspond to Ni 2p 3/2 and Ni 2p 1/2 , respectively, indicating the emergence of Ni 2+ and Ni 3+ [ 19 , 20 , 21 ].…”

Biological Influence and Clinical Applications of the Unique Flower Shape of ZnO–ZnS@SA Superhydrophobic Composite Films Grown on Nanorods

“…45 The NiS is obtained by the reaction equation (CH 3 COO) 2 Ni + (NH 2 ) 2 CS +2H 2 O → 2CH 3 COONH 4 + NiS + CO 2 , and Ni(OH) 2 is caused by insufficient vulcanization during the hydrothermal process. 46,47 In order to further explore the functional groups on the superhydrophobic surface, the FTIR spectra of pure SA, superhydrophilic ZnO−ZnS, and superhydrophobic ZnO− ZnS@SA surfaces were recorded (see, Figure 3c). It has been verified by the comparison of the FTIR spectra of pure SA and ZnO−ZnS@SA.…”

Design and Construction of Cu(OH)2/Ni3S2 Composite Electrode on Cu Foam by Two-Step Electrodeposition

“…Recently, transition metal sulfides-especially nickel sulfide-such as NiS, Ni3S2, Ni9S8 have attracted extensive attention as a promising cathode for supercapacitors [1][2][3]. Compared with their corresponding oxides and hydroxides, transition metal sulfides have better conductivity and electrochemical activity due to the lower electronegativity of sulfur [4,5].…”