Single-nanowire photoelectrochemistry

Abstract

Photoelectrochemistry is one of several promising approaches for the realization of efficient solar-to-fuel conversion. Recent work has shown that photoelectrodes made of semiconductor nano-/microwire arrays can have better photoelectrochemical performance than their planar counterparts because of their unique properties, such as high surface area. Although considerable research effort has focused on studying wire arrays, the inhomogeneity in the geometry, doping, defects and catalyst loading present in such arrays can obscure the link between these properties and the photoelectrochemical performance of the wires, and correlating performance with the specific properties of individual wires is difficult because of ensemble averaging. Here, we show that a single-nanowire-based photoelectrode platform can be used to reliably probe the current-voltage (I-V) characteristics of individual nanowires. We find that the photovoltage output of ensemble array samples can be limited by poorly performing individual wires, which highlights the importance of improving nanowire homogeneity within an array. Furthermore, the platform allows the flux of photogenerated electrons to be quantified as a function of the lengths and diameters of individual nanowires, and we find that the flux over the entire nanowire surface (7-30 electrons nm(-2) s(-1)) is significantly reduced as compared with that of a planar analogue (∼1,200 electrons nm(-2) s(-1)). Such characterization of the photogenerated carrier flux at the semiconductor/electrolyte interface is essential for designing nanowire photoelectrodes that match the activity of their loaded electrocatalysts.

Conductive-probe atomic force microscopy as a characterization tool for nanowire-based solar cells

“…The NW-to-NW fluctuations in series resistance lead to broad range in current density between them, resulting in preventing some of the NWs to emit light. Also, in the use of NWs for photoelectrochemistry experiments, it was observed that the photovoltage of the NW array photoelectrode is highly affected by the worst-performing NW [36]. Our original approach here consists of addressing some of these issues in our devices in a more systematic way by C-AFM.…”

One‐Dimensional Earth‐Abundant Nanomaterials for Water‐Splitting Electrocatalysts

“…Substantially research efforts have been invested into the synthesis of these 1D materials, which allow for exquisite controls of composition, morphology, heterostructures, and reactivity 28, 29. The capability of modulation the composition and doping, either radially or even longitudinally, even within a single 1D nanostructure has been explicitly demonstrated 30, 31.…”

“…The capability of modulation the composition and doping, either radially or even longitudinally, even within a single 1D nanostructure has been explicitly demonstrated 30, 31. Thus, these achievements have also brought substantial advances and breakthroughs in the applications of utilization of 1D materials in almost all fields of modern technologies,29, 32, 33, 34 including the water splitting electrocatalysts.…”

A coarse-grained Monte Carlo approach to diffusion processes in metallic nanoparticles

“…Special focus will be set on wireshaped nanostructures due to their potential applications in circuits or nanodevices [5,6], as membranes [7], biosensors [8][9][10], transparent electrodes [11], waveguides [12] or antennae in photochemistry [13].…”