Small Change, Big Difference: Photoelectrochemical Behavior of Au Nanocluster-Sensitized TiO₂ Altered by Core Restructuring

Abstract

Ultrasmall gold nanoclusters (Au NCs) have recently gained enormous popularity as a newly emerging light harvester, but many fundamental aspects of their photoelectrochemical behavior are still largely unknown. Unlike traditional photoactive nanoparticles, the NC's core structure, rather than its size, is a key factor that dictates the physical properties of NCs because of a strong quantum confinement effect. Despite this importance, no effort has been made to elucidate the effect of the core structure on the photoelectrochemistry of Au NC-sensitized TiO 2 (Au NC−TiO 2 ). Using Au 25 NC as a model system, we delicately tailored the icosahedral Au 13 core of Au 25 NC into a cuboctahedral Au 15 core of Au 23 NC. This subtle core manipulation has a drastic impact on the entire interfacial behavior of Au NC−TiO 2 , which in turn significantly affects the photoelectrochemical performance. This new insight highlights the overlooked effect of the core structure on the photoelectrochemistry of Au NC−TiO 2 .

Understanding the Photoelectrochemical Behavior of Metal Nanoclusters: A Perspective

“…Our group demonstrated this behavior on Au 25 (SR) 18 NCs as a model system . We used a simple chemical etching process to transform Au 25 (SR) 18 to Au 23 (SR) 16 NCs.…”

Similar Looks, Different Photoelectrochemical Behavior: Unique Aspects of Metal-Nanocluster-Sensitized Electrodes

“…The 29-fold increase in the photocurrent generation capacity of Au NC-sensitized solar cells since their inception (from 290 μA cm –2 to 8.45 mA cm –2 ) highlights their efficient ability to convert photons into electrical energy. , Furthermore, modulating the electronic structure of Au NCs via an appropriate level of Ag doping has also been shown to be an effective strategy to improve the PCE of MCSSCs . Along with the doping, core restructuring of Au NCs is also a novel strategy to boost the performance of MCSSCs . In addition to Au NCs, stable photocurrent generation from Ag NCs has also been demonstrated, which could open new avenues to put research efforts toward non-Au NC-based sensitizers and help to reduce the overall cost of NC-based devices .…”

“…47 Along with the doping, core restructuring of Au NCs is also a novel strategy to boost the performance of MCSSCs. 48 In addition to Au NCs, stable photocurrent generation from Ag NCs has also been demonstrated, which could open new avenues to put research efforts toward non-Au NC-based sensitizers and help to reduce the overall cost of NC-based devices. 6 However, despite the strides made so far, the PCE of MCSSCs still lags far behind those of their competitors, such as DSSCs and QDSSCs, which is significant because the optimal design of MCSSCs has not yet been obtained.…”

Gold Nanoclusters as Electrocatalysts: Atomic Level Understanding from Fundamentals to Applications

“…These properties are different from those of conventional Au NPs. Because of these intriguing properties, Au NCs have been applied in a variety of applications such as biomedicine, sensors, catalysis, and light energy conversion systems. ,− Recently, Au NCs are attracting interest, particularly in electrocatalysis applications, and those studies have shown that Au NCs would be promising materials for the future of electrocatalysis research. − …”