Morphological and structural evolution of gas-phase synthesized vanadium nanoparticle films induced by thermal treatment

Plasma-assisted synthesis of vanadium oxide/metal nanostructures for Surface-enhanced Raman scattering (SERS) spectroscopy

“…As can be seen in Figure 2, where are presented examples of SEM images of V NPs acquired immediately after their deposition and after their annealing in the air at the temperature of 450 o C for 30 minutes, the originally close-to-spherical V NPs (mean diameter of 40 nm) undergo upon heating significant morphological changes; the NPs grow into much bigger rod-like structures with lengths exceeding 100 nm. As demonstrated in our previous study [9], such changes in the morphology of the samples are accompanied by the structural transformation of initially metallic NPs into fully crystalline vanadium pentoxide NPs. Despite these changes, the NPs films retain their high porosity characterized by a high surface-to-volume ratio, i.e., a property that assures a large amount of analyte-surface interaction sites needed for an effective photoinduced CT required for CM SERS enhancement.…”

“…In order to transform vanadium NPs into vanadium pentoxide ones, the as-deposited nanoparticle films were annealed in an industrial furnace (MP05-0.1, Alexandr Martínek Laboratorní pece) on air. Based on the previous investigations, the annealing temperature was 450 o C and the annealing time was 60 minutes, which led to the complete structural transformation of predominately metallic V NPs to purely crystalline V2O5 NPs [9].…”

New Insights into SERS Mechanism of Semiconductor–Metal Heterostructure: A Case Study on Vanadium Pentoxide Nanoparticles Decorated with Gold

“…After the preset annealing duration, which was in our case 30 min, the samples were allowed to cool down to room temperature. As we have shown previously, this procedure assured the transformation of initially predominately metallic vanadium to the crystalline V 2 O 5 phase.…”

“…The procedure employed for the preparation of samples is schematically depicted in Figure S1. Vanadium NPs were fabricated using a custom-built, magnetron-based gas aggregation source (GAS) of NPs described in detail in our previous works. ,, The NP source used a 3 in., water-cooled planar magnetron mounted in a water-cooled, stainless steel aggregation chamber 100 mm in diameter. The magnetron was equipped with a 0.125 in.…”

“…Both experiments and simulations showed that these microstructures exhibit the best SERS performance with the detection limit of methylene blue (MB) 5 × 10 –9 M and enhancement factor value of 1.18 × 10 6 . Recently, Kočišová et al demonstrated the SERS feasibility of V 2 O 5 NP films prepared using a facile and time-effective solvent- and linker-free deposition procedure that consisted of the gas-phase synthesis of vanadium NPs followed by their thermal annealing above 300 °C . The SERS performance of V 2 O 5 NP films tested by organic dyes was found to be strongly linked with their porosity and the appropriate crystalline structure adjusted by annealing, providing excellent spectral reproducibility with a relative standard deviation (RSD) of the SERS signal of about 11%…”