TY  - JOUR
A1  - Hörmann, Ulrich
A1  - Zeiske, Stefan
A1  - Park, Soohyung
A1  - Schultz, Thorsten
A1  - Kickhoefel, Sebastian
A1  - Scherf, Ullrich
A1  - Blumstengel, Sylke
A1  - Koch, Norbert
A1  - Neher, Dieter
T1  - Direct observation of state-filling at hybrid tin oxide/organic interfaces
JF  - Applied physics letters
N2  - Electroluminescence (EL) spectra of hybrid charge transfer states at metal oxide/organic type-II heterojunctions exhibit bias-induced spectral shifts. The reasons for this phenomenon have been discussed controversially and arguments for either electric field-induced effects or the filling of trap states at the oxide surface have been put forward. Here, we combine the results of EL and photovoltaic measurements to eliminate the unavoidable effect of the series resistance of inorganic and organic components on the total voltage drop across the hybrid device. For SnOx combined with the conjugated polymer [ladder type poly-(para-phenylene)], we find a one-to-one correspondence between the blue-shift of the EL peak and the increase of the quasi-Fermi level splitting at the hybrid heterojunction, which we unambiguously assign to state filling. Our data are resembled best by a model considering the combination of an exponential density of states with a doped semiconductor. Published under license by AIP Publishing.
Y1  - 2019
U6  - https://doi.org/10.1063/1.5082704
SN  - 0003-6951
SN  - 1077-3118
VL  - 114
IS  - 18
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Megow, Jörg
A1  - Körzdörfer, Thomas
A1  - Renger, Thomas
A1  - Sparenberg, Mino
A1  - Blumstengel, Sylke
A1  - Henneberger, Fritz
A1  - May, Volkhard
T1  - Calculating Optical Absorption Spectra of Thin Polycrystalline Organic Films: Structural Disorder and Site-Dependent van der Waals Interaction
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - We propose a new approach for calculating the change of the absorption spectrum of a molecule when moved from the gas phase to a crystalline morphology. The so-called gas-to-crystal shift Delta epsilon(m) is mainly caused by dispersion effects and depends sensitively on the molecules specific position in the nanoscopic setting. Using an extended dipole approximation, we are able to divide Delta epsilon(m)= -QW(m) in two factors, where Q depends only on the molecular species and accounts for all nonresonant electronic transitions contributing to the dispersion while W-m is a geometry factor expressing the site dependence of the shift in a given molecular structure. The ability of our approach to predict absorption spectra is demonstrated using the example of polycrystalline films of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI).
Y1  - 2015
U6  - https://doi.org/10.1021/acs.jpcc.5b01587
SN  - 1932-7447
VL  - 119
IS  - 10
SP  - 5747
EP  - 5751
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - INPR
A1  - Megow, Jörg
A1  - Körzdörfer, Thomas
A1  - Renger, Thomas
A1  - Sparenberg, Mino
A1  - Blumstengel, Sylke
A1  - May, Volkhard
T1  - Reply to "Comment on 'Calculating Optical Absorption Spectra of Thin Polycrystalline Organic Films: Structural Disorder and Site-Dependent van der Waals Interaction"
T2  - The journal of physical chemistry : C, Nanomaterials and interfaces
Y1  - 2015
U6  - https://doi.org/10.1021/acs.jpcc.5b05536
SN  - 1932-7447
VL  - 119
IS  - 32
SP  - 18818
EP  - 18820
PB  - American Chemical Society
CY  - Washington
ER  -