Surface plasmon resonance effect of Ag metallized SnO₂ particles: Exploration of metal induced gap states and characteristic properties of Ohmic junction

Abstract

Ag metallization on the surface of SnO 2 catalyst was performed by the photoreduction method, and its presence was confirmed by the (111), (200), (220), and (311) hkl planes of Ag metal by powder X-ray diffraction technique. Further lattice parameters "a" and "c" of the SnO 2 tetragonal unit cell show prominent changes on metallization. Ultraiolet-visible absorption spectrum of Ag-SnO 2 shows the extended adsorption in the visible region up to almost~565 nm due to the surface plasmon resonance (SPR) effect. Percentage composition of the elements present in the SnO 2 and Ag-SnO 2 samples were confirmed by the energy-dispersive X-ray analysis and the inductively coupled plasma-atomic emission spectroscopic analysis techniques, and the spherical morphology of these samples were confirmed by the scanning electron microscopy. The photoluminescence technique confirms the reduction of recombination of photogenerated charge carriers by 44% in the case of Ag-SnO 2 . The metal-metal oxide contact was found to be Ohmic rather than Schottky. The higher activity of the Ag-SnO 2 nanoparticles are correlated to the SPR effect, metal-induced gap states, inherently created structural defects, the ability of Sn to show multiple oxidation states, variation in the surface oxygen concentration, and also to the Ohmic junction. Synergistic effect between electronic/intrinsic defect energy levels of Ag-SnO 2 photocatalyst with the redox potential of the fast red dye leads to the higher quantum efficiency. K E Y W O R D S band bending, charge carriers, metal deposition, metal-induced gap states, Ohmic junction, photocatalysis, surface plasmon resonance effect

Broad-Band-Enhanced Plasmonic Perovskite Solar Cells with Irregular Silver Nanomaterials

“…First, the outstanding conductivity of Ag NMs, especially those with a nanowire shape, contributes extensively to reducing the series/charge transfer resistance and boosting the carrier mobility . Second, the strong near-field LSPR effect of Ag NMs, especially those with small sizes, facilitates the dissociation of excitons and charge generation. − Third, hot electrons could transfer from the Ag NM surface to the conduction band of neighboring SnO 2 under illumination, leading to increased local electron mobility of ETL, which benefits charge collection. ,, Therefore, although the recombination centers provided by Ag NMs cannot be eliminated due to their inevitable contact with perovskite, a prominently positive impact of Ag NMs on the carrier transport and collection leads to an overall reduction of the electron–hole recombination in devices.…”

“…A well-controlled oxide shell is often required for the metal NMs in this case to avoid direct contact with the active layer and to reduce charge recombination. − The energetic electromagnetic field around the NMs and the scattering effect contribute to enhancing exciton oscillation and light-trapping, resulting in the higher photon-to-electron conversion efficiency. On the other hand, the metal NMs can be also embedded into the electron transport layer (ETL). − Hot electrons can be generated under illumination and transferred from the metal NMs to electron transport materials, such as TiO 2 and SnO 2 . , The electron extraction and transportation are facilitated by LSPR, and presumably, additional photocurrent might be obtained. ,, It is well-known that both scattering characteristics and the near-filed enhancement by LSPR can be manipulated strictly by the size and shape of the NMs, which is also related to the excitation wavelength, absorption spectra, and the plasmon modes of the metal NMs . As a result, limited enhancement responding to a narrow range of wavelengths is usually obtained by monodisperse metal NMs.…”

“…18−22 Hot electrons can be generated under illumination and transferred from the metal NMs to electron transport materials, such as TiO 2 and SnO 2 . 19,22 The electron extraction and transportation are facilitated by LSPR, and presumably, additional photocurrent might be obtained. 8,9,22 It is wellknown that both scattering characteristics and the near-filed enhancement by LSPR can be manipulated strictly by the size and shape of the NMs, which is also related to the excitation wavelength, absorption spectra, and the plasmon modes of the metal NMs.…”

Poly-Extract Synthesized Silver Nanoparticles Catalysed Rhodamine-B and Methyl Orange Dye Degradation: Influence of Physicochemical Parameters and their Recyclability

“…[14,15,[18][19][20]. Among all the metal NPs reported, silver nanoparticles (AgNPs; SNPs) were found to be suitable for their multi-purpose applicability, particularly degradation of textile dyes [21][22][23]. Compared to other noble metal NPs, SNPs are economical, can be easily synthesized in different shapes and sizes [3,24].…”

Sustainable and fast saliva-based COVID-19 virus diagnosis kit using a novel GO-decorated Au/FBG sensor

“…When the resonance condition is satisfied, it gives progress to large extinction coefficients. The peak wavelength, amplitude, and width of SPR depend on the metal layer composition, separation distance, size, shape, and dielectric surrounding environment of the nanolayer [13] , [14] . SPR-based biochemical sensors using optical fiber have been used in the research of Guangyu Qiu et al [15] .…”