Enhancing Hot Carrier Collection for Solar Water Splitting with Plasmonic Titanium Nitride

TL;DR

This paper demonstrates that plasmonic titanium nitride nanoparticles significantly improve hot carrier collection and photocurrent in solar water splitting, outperforming gold nanoparticles due to better absorption and electron collection properties.

Contribution

It introduces titanium nitride as a cost-effective, durable plasmonic material that enhances hot carrier generation and collection in solar water splitting devices.

Findings

TiN nanoparticles produce 25% higher photocurrent than Au nanoparticles.

TiN offers superior hot carrier generation due to better absorption and electron mean free path.

TiN forms an Ohmic junction with TiO2, enabling efficient electron collection.

Abstract

The use of hot electrons generated from the decay of surface plasmons is a new paradigm to increase the conversion yield in solar energy technologies. Titanium nitride (TiN) is an emerging plasmonic ceramic that offers compatibility with CMOS technology, corrosion resistance, as well as mechanical strength and durability thus outperforming noble metals (i.e., Au, Ag) in terms of cost, mechanical, chemical and thermal stability. Here, we show that plasmonic TiN nanoparticles produce 25% higher photocurrent enhancement than Au nanoparticles decorated on TiO2 nanowires for photoelectrochemical water splitting. Our results highlight that TiN offers superior performance in hot carrier generation due to enhanced absorption efficiency, increased electron mean free path, and the ability to form an Ohmic junction with TiO2, thus enabling an extremely efficient electron collection not achievable with plasmonic Au nanoparticles. Our findings show that transition metal nitrides enable practical plasmonic devices with enhanced performance for solar energy conversion.