Tunable photo-induced electronic property of octahedral metal clusters

Thi Kim Ngan Nguyen,Fabien Grasset,Noée Dumait,Stéphane Cordier,David Berthebaud,Naoki Ohashi,Tetsuo Uchikoshi

doi:10.1016/j.mlblux.2021.100079

Abstract

The tunable photo-induced electronic property of the Cs2[{Mo6Bri8}Bra6] and Br2[{Ta6Bri12}(H2O)a6] octahedral metal cluster-based compounds was characterized by the zeta potential measurement upon irradiation by ultraviolet–visible (UV–Vis) light. The enhancement of the electronic charge on the surface of the [{Mo6Bri8}Bra6]2- cluster-based anion caused by the irradiation increased the negative zeta potential. Both compounds showed the dependence of the zeta potential as a function of the light excitation. This will be a promising property for sensor applications based on the reversibility of the photo-electrochemical properties of the functional cluster.

Highlights

Multifunctional materials based on the integration of an organic–inorganic atomic integrated system that demonstrate the reversibility of redox transformation, photochemistry, or electrochemistry are attracting attention for energy-saving applications such as photovoltaics [1] and light-emitting diodes (LEDs) [2]
We report in this study the dependence of the zeta potential as a function of the light excitation wavelength for the [{Mo6Bri8} Bra6]2- anionic cluster unit and the cationic [{Ta6Bri12}(H2O)a6]4+ cluster units
With the existence of an electron in a valence band, the cluster can be oxidized during the excitation by light irradiation in the required range, which was observed by the change in the zeta potential (ZP) of the charged particle surface in an electric field

Summary

Introduction

Multifunctional materials based on the integration of an organic–inorganic atomic integrated system that demonstrate the reversibility of redox transformation, photochemistry, or electrochemistry are attracting attention for energy-saving applications such as photovoltaics [1] and light-emitting diodes (LEDs) [2]. The metal atom cluster (MC) family, which is built either on an edge-bridged {M6(l2-X)i12} (M = Ta, Nb, W) or face-capped {M6(l3-X)i8} (M = Mo, Re) metallic cluster core (Xi = I, Br, Cl) coordinated with apical ligands (La = I, Br, Cl, H2O, OH) with a nanometer size (under 2 nm) exhibiting photochemical and photophysical [3], luminescent [4], and redox properties [5], have been extensively studied. The detailed studies are progressing to determine a new tunable process between the electronic, optical, and chemical properties of the cluster by using further techniques. We first investigated the effect of the light absorbing characteristic on the charging property by excited electron transfer in the [{Mo6(l3-Br)i8}Bra6]2- cluster and [{Ta6(l2-Br)i12}(H2O)a6]2+ cluster units. An electro-osmosis analysis was used to measure the zeta potential on the charged surface of the cluster unit in an organic solvent during light irradiation.

Experimental

Results and discussion

Conclusions