Plasmon-induced charge separation at two-dimensional gold semishell arrays on SiO2@TiO2 colloidal crystals

Abstract

Photoelectrodes based on plasmonic Au semishell (or halfshell) arrays are developed. A colloidal crystal consisting of SiO2@TiO2 core-shell particles is prepared on a TiO2-coated transparent electrode. A Au semishell (or halfshell) array is deposited by sputtering or evaporation on the colloidal crystal. An electrode with the semishell (or halfshell) array exhibits negative photopotential shifts and anodic photocurrents under visible light at 500-800 nm wavelengths in an aqueous electrolyte containing an electron donor. In particular, hydroquinone and ethanol are good electron donors. The photocurrents can be explained in terms of plasmon-induced charge separation at the Au-TiO2 interface.

Plasmon-induced charge separation: chemistry and wide applications

“…9d–f ). 74 , 86 , 88 Devices relatively selective to linearly 42 or circularly 89 polarized light have also been reported ( Fig. 9b and c , respectively).…”

“…PICS is usually based on LSPR, but propagating surface plasmon resonance at metal film surfaces is also reported to cause PICS. 73 In the case of a nanostructured but continuous plasmonic film, 74 both localized and propagating plasmons may contribute to PICS. However, details are yet known because analysis of the localized and propagating modes is complicated.…”

Ordered array of Ag semishells on different diameter monolayer polystyrene colloidal crystals: An ultrasensitive and reproducible SERS substrate

“…The transition dipoles of nanoparticles will produce the plasmonic couple when the nanoparticles close to each other. These plasmonic couple around each particle can provide enhanced electromagnetic fields 36 . The plasmon resonance will shift to red when the distance of gaps region between the adjacent AgSS decreases along the increase in diameter.…”

Two‐Dimensional Arrays of Au Halfshells with Different Sizes for Plasmon‐Induced Charge Separation

“…We developed a photoelectrode on the basis of two‐dimensional (2D) Au halfshell arrays on SiO 2 @TiO 2 core‐shell colloidal crystals (Figure b) and studied its photoelectrochemical behavior under visible or near infrared (NIR) irradiation in a wet cell . PICS occurs at the interface between the outer Au halfshell and the inner TiO 2 shell, and the electrons injected from the Au halfshell to the TiO 2 shell are transported to the indium tin oxide (ITO) electrode, while the positive charges on the Au halfshell are used for oxidation of chemical species such as ethanol in the solution.…”