“…Meanwhile, due to the wide bandgap of Zn‐based II–VI semiconductors (bulk ZnSe: 2.82 eV; bulk ZnS: 3.7 eV), these NPs absorb near ultraviolet (UV) and blue light from solar spectrum, unlike the traditional Cd‐based nanocrystals absorbing visible light. Given the main purpose for this project is to investigate the positional tipping effect from Au onto ZnSe nanorods on photocatalysis, the complementary absorption of longer wavelength photons to maximize solar harvesting for photocatalysis enhancement is expectable by heterojunction and doping strategies . These merits make them potential supplements or alternatives to the Cd‐based materials in photocatalytic hydrogen generation and biomedical applications .…”
For the first time, colloidal gold (Au)–ZnSe hybrid nanorods (NRs) with controlled size and location of Au domains are synthesized and used for hydrogen production by photocatalytic water splitting. Au tips are found to grow on the apices of ZnSe NRs nonepitaxially to form an interface with no preference of orientation between Au(111) and ZnSe(001). Density functional theory calculations reveal that the Au tips on ZnSe hybrid NRs gain enhanced adsorption of H compared to pristine Au, which favors the hydrogen evolution reaction. Photocatalytic tests reveal that the Au tips on ZnSe NRs effectively enhance the photocatalytic performance in hydrogen generation, in which the single Au‐tipped ZnSe hybrid NRs show the highest photocatalytic hydrogen production rate of 437.8 µmol h−1 g−1 in comparison with a rate of 51.5 µmol h−1 g−1 for pristine ZnSe NRs. An apparent quantum efficiency of 1.3% for hydrogen evolution reaction for single Au‐tipped ZnSe hybrid NRs is obtained, showing the potential application of this type of cadmium (Cd)‐free metal–semiconductor hybrid nanoparticles (NPs) in solar hydrogen production. This work opens an avenue toward Cd‐free hybrid NP‐based photocatalysis for clean fuel production.
“…Meanwhile, due to the wide bandgap of Zn‐based II–VI semiconductors (bulk ZnSe: 2.82 eV; bulk ZnS: 3.7 eV), these NPs absorb near ultraviolet (UV) and blue light from solar spectrum, unlike the traditional Cd‐based nanocrystals absorbing visible light. Given the main purpose for this project is to investigate the positional tipping effect from Au onto ZnSe nanorods on photocatalysis, the complementary absorption of longer wavelength photons to maximize solar harvesting for photocatalysis enhancement is expectable by heterojunction and doping strategies . These merits make them potential supplements or alternatives to the Cd‐based materials in photocatalytic hydrogen generation and biomedical applications .…”
For the first time, colloidal gold (Au)–ZnSe hybrid nanorods (NRs) with controlled size and location of Au domains are synthesized and used for hydrogen production by photocatalytic water splitting. Au tips are found to grow on the apices of ZnSe NRs nonepitaxially to form an interface with no preference of orientation between Au(111) and ZnSe(001). Density functional theory calculations reveal that the Au tips on ZnSe hybrid NRs gain enhanced adsorption of H compared to pristine Au, which favors the hydrogen evolution reaction. Photocatalytic tests reveal that the Au tips on ZnSe NRs effectively enhance the photocatalytic performance in hydrogen generation, in which the single Au‐tipped ZnSe hybrid NRs show the highest photocatalytic hydrogen production rate of 437.8 µmol h−1 g−1 in comparison with a rate of 51.5 µmol h−1 g−1 for pristine ZnSe NRs. An apparent quantum efficiency of 1.3% for hydrogen evolution reaction for single Au‐tipped ZnSe hybrid NRs is obtained, showing the potential application of this type of cadmium (Cd)‐free metal–semiconductor hybrid nanoparticles (NPs) in solar hydrogen production. This work opens an avenue toward Cd‐free hybrid NP‐based photocatalysis for clean fuel production.
“…[34][35][36] In the past few years, some ZnO/ ZnSe nanocomposites have been successfully fabricated. [37][38][39] Although there are some reports about the synthesis of ZnO/ ZnSe thin films, the use of ZnO/ZnSe thin films for water oxidation in PEC cells is limited. The activity of this catalyst is shown to be closely associated with its shape and surface structure.…”
In this study, a ZnO/ZnSe nanonail array was prepared via a two-step sequential hydrothermal synthetic route. In this synthetic process, the ZnO nanorod array was first grown on a fluorine-doped tin oxide (FTO) substrate using a seed-mediated growth approach via the hydrothermal process. Then, the ZnO nanonail array was obtained via in situ growth of ZnSe nano caps onto the ZnO nanorod array via a hydrothermal process in the presence of a Se source. The surface morphology and amount of ZnSe grown on the surface of the ZnO nanorods can be regulated by varying the reaction time and reactant concentration. Compared with pure ZnO nanorods, this unique nanonail array heterostructure exhibits enhanced visible light absorption. The transient photocurrent condition, in combination with steady-state and time-resolved photoluminescence spectroscopy, reveals that the ZnO/ZnSe nanonail array electrode has the highest charge separation rate, highest electron injection efficiency, and highest chemical stability. The photocurrent density of the ZnO/ZnSe nanonail array heterostructure reaches 1.01 mA cm(-2) at an applied potential of 0.1 V (vs. Ag/AgCl), which is much higher than that of the ZnO/ZnSe nanorod array (0.71 mA cm(-2)), the pristine ZnO nanorod array (0.39 mA cm(-2)), and the ZnSe electrode (0.21 mA cm(-2)), indicating its significant visible light driven activities for photoelectrochemical water oxidation. This unique morphology of nail-capped nanorods might be important for providing better insight into the correlation between heterostructure and photoelectrochemical activity.
“…The increased shell thickness is helpful for the light absorption, but it will decrease the charge separation efficiency due to the increased diffusion length of the photon-generated carriers. In this work, the shell of 50 nm in thickness was grown according to the relevant reports [20,40], and further optimization is potential to improve cell performance. In the light of these, multiple factors, including effective bandgap, crystal quality, band structure, and shell thickness, etc., should be comprehensively considered to achieve a high-efficiency nanowire solar cell.Figure 7PL decay times for different samples annealed under 350°C.…”
ZnO/ZnxCd1-xSe coaxial nanowires (NWs) have been successfully synthesized by combining chemical vapor deposition with a facile alternant physical deposition method. The shell composition x can be precisely tuned in the whole region (0 ≤ x ≤ 1) by adjusting growth time ratio of ZnSe to CdSe. As a result, the effective bandgaps of coaxial nanowires were conveniently modified from 1.85 eV to 2.58 eV, almost covering the entire visible spectrum. It was also found that annealing treatment was in favor of forming the mixed crystal and improving crystal quality. An optimal temperature of 350°C was obtained according to our experimental results. Additionally, time resolved photo-luminescence spectra revealed the longest carrier lifetime in ZnO/CdSe coaxial nanowires. As a result, the ZnO/CdSe nanowire cell acquired the maximal conversion efficiency of 2.01%. This work shall pave a way towards facile synthesis of ternary alloys for photovoltaic applications.
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