Experimental determination of work function of silver alloys

Lefort, A.; Akbi, Mohamed; Parizet, M.J.

doi:10.1117/12.174567

Cited by 12 publications

(8 citation statements)

References 2 publications

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“…60 times) that by TNW (Figure 8 and Figure S6). The highest photocatalytic activities of platinum-modified samples agreed with the highest work function of Pt (5.7 eV vs. 5.1 eV (Au) and 4.3 eV (Ag)) [94,95,96], and thus formed Schottky barriers resulting in hindering of charge carriers’ recombination, as well as with the smallest overvoltage for hydrogen evolutions. It should be pointed that OAP samples after modification with NM showed much higher photocatalytic activity than that of respective TNW samples, especially for Au and Pt (Au/OAP and Pt/OAP were ca.…”

Section: Resultsmentioning

confidence: 87%

Influence of Semiconductor Morphology on Photocatalytic Activity of Plasmonic Photocatalysts: Titanate Nanowires and Octahedral Anatase Nanoparticles

et al. 2019

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Octahedral anatase particles (OAP) with eight exposed and thermodynamically most stable (101) facets were prepared by an ultrasonication-hydrothermal (US-HT) reaction from potassium titanate nanowires (TNW). The precursor (TNW) and the product (OAP) of US-HT reaction were modified with nanoparticles of noble metals (Au, Ag or Pt) by photodeposition. Samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), scanning transmission electron microscopy (STEM) and time-resolved microwave conductivity (TRMC). The photocatalytic activity was investigated in three reaction systems, i.e., anaerobic dehydrogenation of methanol and oxidative decomposition of acetic acid under UV/vis irradiation, and oxidation of 2-propanol under vis irradiation. It was found that hydrogen liberation correlated with work function of metals, and thus the most active were platinum-modified samples. Photocatalytic activities of bare and modified OAP samples were much higher than those of TNW samples, probably due to anatase presence, higher crystallinity and electron mobility in faceted NPs. Interestingly, noble metals showed different influence on the activity depending on the semiconductor support, i.e., gold-modified TNW and platinum-modified OAP exhibited the highest activity for acetic acid decomposition, whereas silver- and gold-modified samples were the most active under vis irradiation, respectively. It is proposed that the form of noble metal (metallic vs. oxidized) as well as the morphology (well-organized vs. uncontrolled) have a critical effect on the overall photocatalytic performance. TRMC analysis confirmed that fast electron transfer to noble metal is a key factor for UV activity. It is proposed that the efficiency of plasmonic photocatalysis (under vis irradiation) depends on the oxidation form of metal (zero-valent preferable), photoabsorption properties (broad localized surface plasmon resonance (LSPR)), kind of metal (silver) and counteraction of “hot” electrons back transfer to noble metal NPs (by controlled morphology and high crystallinity).

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Section: Resultsmentioning

confidence: 87%

Influence of Semiconductor Morphology on Photocatalytic Activity of Plasmonic Photocatalysts: Titanate Nanowires and Octahedral Anatase Nanoparticles

et al. 2019

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“…1. This behavior shows that carrier transport was dominated by bulk-limited conduction rather than by interface-limited conduction despite the significant difference in the work function between the Pt/Ir AFM tip and Ag bottom electrode [47,48]. Fig.…”

Section: Resultsmentioning

confidence: 90%

“…Common device structures in previous results involved electrodes with a high work function, such as p-Si (ɸ ≈ 4.91 eV) [60] or TiN (ɸ ≈ 4.7 to 4.9 eV) [61], and Ohmic contact was maintained at the interface between grain boundaries and the bottom electrode. However, in the experiment performed in the current study, a silver electrode (ɸ ≈ 4.26 eV) [47] was used, and a potential barrier was formed at the interface. Therefore, for flexible electronics involving spontaneous grain boundary passivation in HfO 2-x , a material with a low work function is necessary.…”

Section: Resultsmentioning

confidence: 99%

Grain boundary passivation via balancing feedback of hole barrier modulation in HfO2-x for nanoscale flexible electronics

et al. 2022

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Flexible electronics has attracted considerable attention owing to its enormous potential for practical applications in various fields. However, the massive strain produced during bending degrades the device. Especially at grain boundaries, due to the accumulation of defects, this degradation is exacerbated in flexible electronic devices. The importance of electrically inactivated grain boundaries increases as devices scale down to the nanoscale. Here, we propose an HfO2-x thin film that can be used as an excellent material for flexible electronics with versatile functionality, especially for grain boundary passivation. Various electrical phases of HfO2-x thin films with conducting to insulating behavior, which originates from oxygen deficiency, have been fabricated on flexible substrates. Furthermore, owing to the most stable charge state of oxygen vacancies, oxygen-deficient HfO2-x shows p-type conductivity. Current mapping by conductive atomic force microscopy reveals that current flow is hindered at grain boundaries due to the formation of potential barriers. This phenomenon is also observed in bent flexible thin films on convex and concave molds, leading to tensile and compressive strains, respectively. Although the defect concentration increases because of lattice deformation during bending, more holes are trapped at the grain boundaries, resulting in an increased hole barrier height. We believe that grain boundary passivation through hole barrier modulation during bending would pave the way for advances in hafnia-based nanoscale flexible electronics.

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“…Silver, as a plasmonic metal, strongly enhances the light absorption via surface plasmon resonance (SPR), increasing the number of excited electrons and holes in the catalyst, consequently leading to higher photocatalytic performance [ 12 ]. Ag usually has a higher value of work function (4.3 eV [ 44 ]) than the absolute value of ZnO electron affinity (about 4.1 eV [ 45 ]). When the balance between the Fermi levels is established, the Schottky barrier is formed at ZnO/Ag [ 18 ].…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Methylene Blue Photodegradation Rate Using Laser Synthesized Ag-Doped ZnO Nanoparticles

et al. 2022

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In this work, Ag-doped ZnO nanoparticles are obtained via pulsed laser ablation of the Ag-coated ZnO target in water. The ratio of Ag dopant in ZnO nanoparticles strongly depends on the thickness of the Ag layer at the ZnO target. Synthesized nanoparticles were characterized by XRD, XPS, SEM, EDS, ICP-OES, and UV–VIS spectrophotometry to obtain their crystal structure, elemental composition, morphology and size distribution, mass concentration, and optical properties, respectively. The photocatalytic studies showed photodegradation of methylene blue (MB) under UV irradiation. Different ratios of Ag dopant in ZnO nanoparticles influence the photodegradation rate. The ZnO nanoparticles doped with 0.32% silver show the most efficient photodegradation rate, with the chemical reaction constant of 0.0233 min−1. It exhibits an almost twice as large photodegradation rate compared to pure ZnO nanoparticles, showing the doping effect on the photocatalytic activity.

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Experimental determination of work function of silver alloys

Cited by 12 publications

References 2 publications

Influence of Semiconductor Morphology on Photocatalytic Activity of Plasmonic Photocatalysts: Titanate Nanowires and Octahedral Anatase Nanoparticles

Influence of Semiconductor Morphology on Photocatalytic Activity of Plasmonic Photocatalysts: Titanate Nanowires and Octahedral Anatase Nanoparticles

Grain boundary passivation via balancing feedback of hole barrier modulation in HfO2-x for nanoscale flexible electronics

Enhancement of Methylene Blue Photodegradation Rate Using Laser Synthesized Ag-Doped ZnO Nanoparticles

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