Influence of the Electronic Properties of the Ligand on the Photoelectrochemical Behavior of Au₂₅ Nanocluster-Sensitized TiO₂ Photoanode

Abstract

Atomically precise metal nanoclusters (NCs) have recently emerged as a new class of bifunctional (photoactive and catalytically active) photosensitizers in light energy conversion applications. Despite the size and alloy effects of NCs, no effort has been made to elucidate how the protecting ligand affects the photoelectrochemistry of the NC-sensitized photoelectrodes. With a nanoporous TiO2 array as model support, Au25 NCs protected by various thiol-bearing ligands have been used to prepare four different photoanodes. It is revealed that a subtle change of the ligand from an alkanethiol to an aromatic thiol facilitates the charge transfer between the NC and TiO2, which in turn improves the photoelectrochemical performance of the corresponding photoanode by at least 6 times. This new insight highlights the importance of the electronic properties of the ligand on the design of more efficient NC-sensitized photoelectrodes.

Ultra-stable self-standing Au nanowires/TiO2 nanoporous membrane system for high-performance photoelectrochemical water splitting cells

“…[13][14][15] The processes that might take place at the metal-semiconductor interface are complex. The character of the observed effect is determined by the type of metal (e.g., the junction type depends on the difference in the work functions of metal and TiO 2 ), but also more recently size-dependent behavior was found to be an important aspect to be considered (e.g., single atoms, 16 metal clusters, 17,18 nanoparticles 6 ).…”

“…, the junction type depends on the difference in the work functions of metal and TiO 2 ), but also more recently size-dependent behavior was found to be an important aspect to be considered ( e.g. , single atoms, 16 metal clusters, 17,18 nanoparticles 6 ).…”

Atomically precise thiolate‐protected gold nanoclusters: Current status of designability of the structure and physicochemical properties

“…Aromatic SR ligands are more effective in terms of improving PCE than aliphatic SR ligands (Figure 26E). [322] 6. The use of Au n (SC12) m NCs enhances the performance of organic solar cells based on PTB7:PC 70 BM Reproduced with permission: Copyright 2021, American Chemical Society.…”

Emergent properties in supercrystals of atomically precise nanoclusters and colloidal nanocrystals

“…As such, NCLs find application in catalysis, sensing, and optoelectronic devices. 33,39,[43][44][45][46] Owing to their small size of less than 3 nm, NCLs behave like molecules with electron transitions/excitonic states, unlike plasmonic nanoparticles, which exhibit surface plasmon resonances. 48 In 2008, Jin and co-workers reported the first study on the electronic properties of thiol-stabilized Au 25 NCLs, which were found to be strongly quantum confined.…”