Triplet excitation and electroluminescence from a supramolecular monolayer embedded in a boron nitride tunnel barrier
Publication Date
January 7, 2020
Creators
Description
We show that ordered monolayers of organic molecules stabilized by hydrogen bonding on the surface of exfoliated few-layer hexagonal boron nitride (hBN) flakes may be incorporated into van der Waals heterostructures with integral few-layer graphene contacts forming a molecular/2D hybrid tunneling diode. Electrons can tunnel from through the hBN/molecular barrier under an applied voltage VSD and we observe molecular electroluminescence from an excited singlet state with an emitted photon energy > eVSD, indicating up-conversion by energies up to ~ 1 eV. We show that tunnelling electrons excite embedded molecules into singlet states in a two-step process via an intermediate triplet state through inelastic scattering and also observe direct emission from the triplet state. These heterostructures provide a solid-state device in which spin-triplet states, which cannot be generated by optical transitions, can be controllably excited and provide a new route to investigate the physics, chemistry and quantum spin-based applications of triplet generation, emission and molecular photon up-conversion.
Collection dates:
01.02.2019 - 01.07.2019
Related resources
Subjects (LCSH)
Subjects
Subjects (JACS)
Divisions
University of Nottingham, UK Campus::Faculty of Science::School of Physics and Astronomy
Data type
Raw data files: AFM images (.ibw), photoluminescence and electroluminescence spectra (.ls6 and .txt), current vs. voltage measurement files (.txt), optical microscopy images (.jpg)
Funders
Leverhulme Trust
MEXT
Grant Number
EP/N033906/1
RPG-2016-104
JPMJCR15F3
EP/P020232/1
Data collection method
Optical microscopy, Fluorescence microscopy, Atomic force microscopy, probe station current-voltage measurements
Resource languages
English
Publisher
The University of Nottingham
Date Issued
December 10, 2019
Except where otherwise noted, this item's license is described as
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Name
PTCDI_Devices_Raw_Data.zip
Size
381.26 MB
Format
Unknown
Checksum (MD5)
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