Kinetics of Photoinduced Electron Transfer in Alternately Stacked Eu3+:LaNb2O7– and W2O72– Nanosheets As Demonstrated by f–f Radiative Transition of Doped Eu3+

Abstract

We successfully demonstrated that the kinetics of photoinduced electron transfer (PET) between alternately stacked Eu3+-doped LaNb2O7– (Eu3+:LaNb2O7–) nanosheets and W2O72– nanosheets can be investigated by the millisecond luminescence decay of an emissive relaxation between 4f orbitals of the doped Eu3+. The emission of the doped Eu3+ is triggered by energy transfer (EnT) from the band gap excitation energy of LaNb2O7–, and the EnT process competes with PET from LaNb2O7– to W2O72–, meaning that the kinetics of the PET can be estimated from the time-resolved emission behavior of doped Eu3+. Alternately stacked nanosheets were synthesized by a thiol-ene click reaction of organic moieties immobilized on each nanosheet where the center-to-center distance of neighboring nanosheets was precisely controlled to be 1.94, 2.04, and 2.20 nm by changing the number of carbons in the covalent bridge generated by the thiol-ene click reaction. When the center-to-center distances of neighboring nanosheets were 1.94 and 2...