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Nanoscale Mapping of Photo‐Induced Charge Carriers Generated at Interfaces of a Donor/Acceptor 2D‐Assembly by Light‐Assisted‐Scanning Tunneling Microscopy
Author(s) -
Lombana Andrés,
Battaglini Nicolas,
Zrig Samia,
Lagoute Jérôme,
ChevillotBiraud Alexandre,
Lang Philippe
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202001325
Subject(s) - materials science , photocurrent , acceptor , scanning tunneling microscope , excited state , optoelectronics , charge carrier , quantum tunnelling , photoconductivity , organic semiconductor , electron acceptor , nanotechnology , photochemistry , atomic physics , chemistry , condensed matter physics , physics
Charge transfers between donor (D) and acceptor (A) species at their excited state in a light‐assisted STM setup (LA‐STM) are investigated. Through an all‐solution process, supramolecular architectures deposited on the Au(111) surface and made of 2D islands of PC 71 BM (electron acceptor) on top of a single layer of the polymer PTB7 (electron donor) are elaborated. The STM junction under modulated laser irradiation exhibits a strong background of photothermal signal attributed both to vertical and lateral expansion of the tip. However, from the analysis of differential images obtained at opposite voltages, additional photocurrent peaks located at the PTB7/PC 71 BM interfaces are detected, providing evidence for active charge transfer between D/A species at their excited state. This phenomenon is discussed in the framework of a charge transport model at interfaces in organic electronics systems.