TY  - JOUR
A1  - Zu, Fengshuo
A1  - Warby, Jonathan
A1  - Stolterfoht, Martin
A1  - Li, Jinzhao
A1  - Shin, Dongguen
A1  - Unger, Eva
A1  - Koch, Norbert
T1  - Photoinduced energy-level realignment at interfaces between organic semiconductors and metal-halide perovskites
JF  - Physical review letters
N2  - In contrast to the common conception that the interfacial energy-level alignment is affixed once the interface is formed, we demonstrate that heterojunctions between organic semiconductors and metal-halide perovskites exhibit huge energy-level realignment during photoexcitation. Importantly, the photoinduced level shifts occur in the organic component, including the first molecular layer in direct contact with the perovskite. This is caused by charge-carrier accumulation within the organic semiconductor under illumination and the weak electronic coupling between the junction components.
Y1  - 2021
U6  - https://doi.org/10.1103/PhysRevLett.127.246401
SN  - 0031-9007
SN  - 1079-7114
VL  - 127
IS  - 24
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Zhao, Yuhang
A1  - Opitz, Andreas
A1  - Eljarrat, Alberto
A1  - Kochovski, Zdravko
A1  - Koch, Christoph
A1  - Koch, Norbert
A1  - Lu, Yan
T1  - Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform
BT  - implications for the charge transfer complex of Ag-F(4)TCNQ
JF  - ACS applied nano materials
N2  - In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.
KW  - Ag nanoparticles
KW  - F(4)TCNQ
KW  - phase transfer
KW  - kinetics
KW  - electron transfer
KW  - surface interaction
Y1  - 2021
U6  - https://doi.org/10.1021/acsanm.1c02153
SN  - 2574-0970
VL  - 4
IS  - 11
SP  - 11625
EP  - 11635
PB  - American Chemical Society
CY  - Washington
ER  -