Electron Transport in Graphene-Based Nanosensors for Eu(III) Detection

Abstract

We performed quantum chemistry density functional theory calculations to provide insight and to calculate the response of nanographene (or molecular-graphene)-based sensors using Eu­(III) complexes as a cold surrogate of trivalent actinide ions. We found that the electronic structure of graphene can be affected by its interaction with europium ions as well as with water molecules. We found an increase in electron transfer through the graphene-based device when exposed to a liquid sample of europium nitrate, Eu­(NO3)3, and a decrease when Eu2O3 approaches a graphene oxide surface. Because the detection mechanism of these nanosensors is based on changes in electron transfer when a trivalent europium complex approaches the graphene-based nanosensors, fabricating arrays of these nanosensors is encouraged.

Computational Chemistry Analysis of Hydrodesulfurization Reactions Catalyzed by Molybdenum Disulfide Nanoparticles

“…All quantum chemistry calculations are performed using the GAUSSIAN-09 Program . Density functional theory , with the hybrid functional B3PW91 − is used for all calculations; such a functional has been tested in several type of applications. ,− The LANL2DZ basis-set with effective core potentials is applied for the transition elements Mo and Ni while the 6-31G­(d,p) basis-set , is used for the remaining atoms. Geometry optimization is performed using the Berny method. , A self-consistent convergence threshold of 10 –6 is used for the density matrix and 10 –8 for the root-mean-square and maximum density matrix error.…”

Europium Effect on the Electron Transport in Graphene Ribbons

“…In any I−V type of sensor, the shape of the I−V is what determines the nature of the agent to be sensed. However, on the question of how selective is graphene for the detection of Eu, we have reported 20 , showing different shapes of I−V curves; thus, we expect that any other moiety will most likely show different I−V behavior.…”

“…For aqueous systems, Kumar et al 20 reported a change in the electrical conductance of graphene ribbons when europium nitrate bonds to graphene. However, the change in the electrical conductance of graphene is practically negligible when the europium ion is coordinated by three nitrate ions and water molecules, yielding a more stable complex than the cases with only one or two nitrate counterions.…”

“…In any I – V type of sensor, the shape of the I – V is what determines the nature of the agent to be sensed. However, on the question of how selective is graphene for the detection of Eu, we have reported the effect on the I – V from several possible moieties such as Eu 2 O 3 , Eu­(NO 3 ) 3 , Eu­(NO 3 ) 3 (H 2 O) 4 , Eu­(NO 3 ) 2 (H 2 O) 5 + , and Eu­(NO 3 )­(H 2 O) 7 2+ , showing different shapes of I – V curves; thus, we expect that any other moiety will most likely show different I – V behavior.…”

Photo-modulated wide-spectrum chromism in Eu3+ and Eu3+/Tb3+ photochromic coordination polymer gels: application in decoding secret information

“…The data of the lifetime for Eu-pcCPG-O and Eu-pcCPG-C were tted using bi-exponential decay, 69 indicating the presence of two distinct emitting centres which are most likely to appear due to two different coordination environments around the Eu 3+ centre in the Eu-pcCPG. The Eu 3+ centre in Eu-pcCPG carries two terpyridine units (occupying six coordination sites) and the remaining two coordination sites could be occupied by the water or nitrate anions or both (one water and one nitrate anion), 70,71 which leads to the Eu 3+ centres in two different coordination environments. This would change the ligand eld strength around the Eu 3+ centre in Eu-pcCPG that eventually results in the biexponential decay.…”