Interlayer charge transfer coupled with acoustic phonon in organic/inorganic van der Waals stacked heterostructures: Self-assembled Pt(II) complex on a PtSe2 monolayer
Journal
Journal of Physical Chemistry C
Journal Volume
124
Journal Issue
46
Pages
25538-25546
Date Issued
2020
Author(s)
Abstract
Interlayer charge-transfer (CT) excitons in heterostructures are of great importance because of their crucial roles in manipulating the device performance and many-body quantum behaviors. Nonetheless, enigmas arise in organic/inorganic heterointerfaces because localized excitons and inhomogeneity in organic materials hinder the interlayer CT processes. Here, we demonstrate that the interlayer CT excitons form in the new organic/inorganic heterostructure composed by the Pt(II) complex 4Me and monolayered transition-metal dichalcogenide PtSe2. The “edge-on” alignment of 4Me is resolved by high-resolution transmission electron microscopy and grazing-incidence X-ray diffraction. Photoelectron spectroscopies verify that the interlayer CT was promoted by the type-II energy band alignment. Moreover, steady-state vis/NIR spectroscopy captures the interlayer CT optical transition and transient absorption spectroscopies unveil the fast charge separation (0.4 ps) coupled with the out-of-plane acoustic phonon mode (0.40 THz) from the PtSe2 monolayer, followed by the slow charge recombination (0.86 μs). This work systematically characterizes the morphology of the 2D heterointerface and the photophysical mechanism of interlayer CT processes, which expand the vision of the material design in organic/inorganic heterostructures and monolayer-based devices. ? 2020 American Chemical Society
Subjects
Acoustic spectroscopy
Alignment
Charge transfer
Electromagnetic wave emission
Excitons
High resolution transmission electron microscopy
Monolayers
Phonons
Photoelectron spectroscopy
Selenium compounds
Terahertz spectroscopy
Transition metals
Van der Waals forces
Charge recombinations
Charge separations
Device performance
Energy-band alignment
Grazing incidence X-ray diffraction
Transient absorption spectroscopies
Transition metal dichalcogenides
Vis/NIR spectroscopy
Platinum compounds
Type
journal article