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Blue Emission from Charge-Transfer Excitons in Hybrid Organic–Inorganic Quantum Wires: (ABT) [PbCl3]
journal contribution
posted on 2019-10-18, 21:13 authored by O. Medhioub, H. Barkaoui, A. Samet, S. Pillet, S. Triki, Y. AbidOrganic–inorganic
hybrid (OIH) materials have the potential
of providing synergetic properties and promising novel optical properties.
This work focuses on the charge-transfer (CT) excitons which play
a critical role in a new OIH material, with formula (C7H7N2S) [PbCl3] abbreviated as ABTPbCl3. Its crystal structure is built up from edge-sharing [PbCl6] octahedra, forming one-dimensional infinite double chains
surrounded by 2-aminobenzothiazole (ABT) organic molecules. The density
of states calculations demonstrate that ABTPbCl3 has a
type-II band alignment, where the valence band and conduction band
of the inorganic wires lie upon those of the organic component, respectively.
Under UV excitation, the photoluminescence spectrum of ABTPbCl3 shows a band emission centered at 483 nm. Based on the band
alignment, we attribute this bluish emission to CT excitons, which
have a lifetime of 5.64 ns. The carrier dynamics is investigated by
measuring the luminescence spectra as a function of temperature. At
temperature below 210 K, the recombination of carriers is dominated
by delocalized excitons, while the mixture of delocalized excitons,
electrons, and holes is dominating at higher temperature.