Water Oxidation under Modal Ultrastrong Coupling Conditions Using Gold/Silver Alloy Nanoparticles and Fabry–Pérot Nanocavities

Abstract

We developed a photoanode consisting of Au‐Ag alloy nanoparticles (NPs), a TiO2 thin film and a Au film (AATA) under modal strong coupling conditions with a large splitting energy of 520 meV, which can be categorized into the ultrastrong coupling regime. We fabricated a photoanode under ultrastrong coupling conditions to verify the relationship between the coupling strength and photoelectric conversion efficiency and successfully performed efficient photochemical reactions. The AATA photoanode showed a 4.0 % maximum incident photon‐to‐current efficiency (IPCE), obtained at 580 nm, and the internal quantum efficiency (IQE) was 4.1 %. These results were attributed to the high hot‐electron injection efficiency due to the larger near‐field enhancement and relatively negative potential distribution of the hot electrons. Furthermore, hybrid mode‐induced water oxidation using AATA structures was performed, with a Faraday efficiency of more than 70 % for O2 evolution.

Bonding states of gold/silver plasmonic nanostructures and sulfur-containing active biological ingredients in biomedical applications: a review

“…47 Also, other anisotropic metallic NPs, the same as AuNRs, exhibit an anisotropic distribution of improved localized electric fields in their surface vicinity. 48,49 LSPR is a potential candidate for developing plasmonic NA biosensors with a high sensitivity, with metallic nanoparticles or nanostructures (NPs/NSs) being excited by an electromagnetic field forming nanostructures with a wavelength similar to the incident light., [50][51][52] as shown in Fig. 1a.…”

“…LSPR is a potential candidate for developing plasmonic NA biosensors with a high sensitivity, with metallic nanoparticles or nanostructures (NPs/NSs) being excited by an electromagnetic field forming nanostructures with a wavelength similar to the incident light., 50–52 as shown in Fig. 1a.…”

Unconventional strategies to break through the efficiency of light‐driven water splitting: A review

“…Such strong coupling model not only expanded the light harvesting range of the system but also promoted the hot electron transfer from Au‐NPs to TiO 2 , which totally resulted in enhanced water oxidation quantum efficiency. The authors' group continued to explore USC conditions using Au/Ag alloy NPs and Fabry–Pérot nanocavities of TiO 2 /Au‐film for OER reaction, giving a Rabi splitting energy of 620 meV, which resulted in a maximum internal quantum efficiency of 4.1% at 580 nm and Faraday efficiency of >70% for O 2 evolution 64 ; as for HER, the same group explored the Au‐NP/NiO/Pt‐film to construct a strong coupling system with a Rabi splitting energy of 200 meV and IPCE of 0.45% at 650 nm in the electrolyte of 0.1 M KClO 4 and 0.1 M K 2 S 2 O 8 68 . All these discoveries combining Fabry–Pérot nanocavities exhibit promising features; however, the yielded hydrogen or oxygen evolution rates remain relatively small due to the limited amount of hot spots from the low coverage of plasmonic nanostructures, generally <25%.…”