Gold nanoparticles physicochemically bonded onto tungsten disulfide nanosheet edges exhibit augmented plasmon damping

Abstract

Augmented plasmonic damping of dipole-resonant gold (Au) nanoparticles (NP) physicochemically bonded onto edges of tungsten disulfide (WS2) nanosheets, ostensibly due to hot electron injection, is quantified using electron energy loss spectroscopy (EELS). EELS allows single-particle spatial resolution. A measured 0.23 eV bandwidth expansion of the localized surface plasmon resonance upon covalent bonding of 20 nm AuNP to WS2 edges was deemed significant by Welch’s t-test. Approximately 0.19 eV of the measured 0.23 eV expansion went beyond conventional radiative and nonradiative damping mechanisms according to discrete dipole models, ostensibly indicating emergence of hot electron transport from AuNP into the WS2. A quantum efficiency of up to 11±5% spanning a 7 fs transfer process across the optimized AuNP-TMD ohmic junction is conservatively calculated. Putative hot electron transport for AuNP physicochemically bonded to TMD edges exceeded that for AuNP physically deposited onto the TMD basal plane. This arose from contributions due to (i) direct physicochemical bond between AuNP and WS2; (ii) AuNP deposition at TMD edge sites; and (iii) lower intrinsic Schottky barrier. This improves understanding of photo-induced doping of TMD by metal NP which could benefit emerging catalytic and optoelectronic applications.

Production of monolayer-rich gold-decorated 2H–WS2 nanosheets by defect engineering

“…Darkfield scanning TEM coincident with electron energy loss spectroscopy performed in parallel with the current work elucidated plasmon damping at the physiochemical WS 2 -Au bond, providing an important first step in understanding energy transfer and edge states in this hybrid material. 44 XPS still shows evidence of a covalent Au-S bond in the purified samples (SI section 7.3). For the purified l-WS 2 -Au1 sample, some of the 10-20 nm diameter AuNPs are still present (wide-view image Fig.…”

Gold Decoration and Photoresistive Response to Nitrogen Dioxide of WS2 Nanotubes

“…[85] As reported by Forcherio et al, [86] hot electrons generatedi np lasmonic gold nanoparticles deposited onto WS 2 readily transfer to the disulfide counterpart in 7f s, with aq uantum efficiency of up to 11 AE 5%.F ormation of ad irect chemicalb ond between gold and an outer sulfur layer of WS 2 plays ab eneficial role in this process, resulting in faster and more efficient hot electron transfer,a sc ompared to AuNPs physically deposited onto MoS 2 nanoflakes. [86,87] Note that our study revealed possible AuÀSb ondingo nt he AuNP/NT-WS 2 interface of the prepared nanocomposites. We suggest that the transfer of hot electrons additionally increases the "light" conductance of Au-NT-WS 2 nanocomposite resulting in the enhanced photoresponse.…”

“…Typically, the excited plasmon in AuNPs has multiple effects on the semiconductor part of the nanocomposite, including energy and charge carrier transfer, amplification of local electrical fields and plasmon‐induced local heating . As reported by Forcherio et al., hot electrons generated in plasmonic gold nanoparticles deposited onto WS 2 readily transfer to the disulfide counterpart in 7 fs, with a quantum efficiency of up to 11±5 %. Formation of a direct chemical bond between gold and an outer sulfur layer of WS 2 plays a beneficial role in this process, resulting in faster and more efficient hot electron transfer, as compared to AuNPs physically deposited onto MoS 2 nanoflakes .…”

Enhanced Catalysis by Optical Nanoantenna Reduced on Transition Metal Dichalcogenide

“…An 11±5% quantum efficiency of HET from ca. 20 nm AuNPs reduced on WS 2 nanosheets was estimated by comparing electron energy loss spectroscopy (EELS) measured and DDA simulation [22].…”