Open AccessMechano-Optical Switching of a Single Molecule with Doublet Emission
Author(s) -
Jiří Doležal,
Pingo Mutombo,
Dachtigallová,
Pavel Jelı́nek,
Pablo Merino,
Martin Švec
Publication year - 2020
Publication title -
acs nano
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.554
H-Index - 382
eISSN - 1936-086X
pISSN - 1936-0851
DOI - 10.1021/acsnano.0c03730
Subject(s) - exciton , materials science , scanning tunneling microscope , quantum tunnelling , ionic bonding , molecule , common emitter , optoelectronics , luminescence , dielectric , coulomb , electronic structure , electron , molecular physics , atomic physics , nanotechnology , condensed matter physics , chemistry , physics , ion , organic chemistry , quantum mechanics
The ability to control the emission from single-molecule quantum emitters is an important step toward their implementation in optoelectronic technology. Phthalocyanine and derived metal complexes on thin insulating layers studied by scanning tunneling microscope-induced luminescence (STML) offer an excellent playground for tuning their excitonic and electronic states by Coulomb interaction and to showcase their high environmental sensitivity. Copper phthalocyanine (CuPc) has an open-shell electronic structure, and its lowest-energy exciton is a doublet, which brings interesting prospects in its application for optospintronic devices. Here, we demonstrate that the excitonic state of a single CuPc molecule can be reproducibly switched by atomic-scale manipulations permitting precise positioning of the molecule on the NaCl ionic crystal lattice. Using a combination of STML, AFM, and ab initio calculations, we show the modulation of electronic and optical bandgaps and the exciton binding energy in CuPc by tens of meV. We explain this effect by spatially dependent Coulomb interaction occurring at the molecule-insulator interface, which tunes the local dielectric environment of the emitter.