TY  - JOUR
A1  - Piersimoni, Fortunato
A1  - Schlesinger, Raphael
A1  - Benduhn, Johannes
A1  - Spoltore, Donato
A1  - Reiter, Sina
A1  - Lange, Ilja
A1  - Koch, Norbert
A1  - Vandewal, Koen
A1  - Neher, Dieter
T1  - Charge Transfer Absorption and Emission at ZnO/Organic Interfaces
T2  - The journal of physical chemistry letters
N2  - We investigate hybrid charge transfer states (HCTS) at the planar interface between a-NPD and ZnO by spectrally resolved electroluminescence (EL) and external quantum efficiency (EQE) measurements. Radiative decay of HCTSs is proven by distinct emission peaks in the EL spectra of such bilayer devices in the NIR at energies well below the bulk a-NPD or ZnO emission. The EQE spectra display low energy contributions clearly red-shifted with respect to the a-NPD photocurrent and partially overlapping with the EL emission. Tuning of the energy gap between the ZnO conduction band and a-NPD HOMO level (E-int) was achieved by modifying the ZnO surface with self-assembled monolayers based on phosphonic acids. We find a linear dependence of the peak position of the NIR EL on E-int, which unambiguously attributes the origin of this emission to radiative recombination between an electron on the ZnO and a hole on a-NPD. In accordance with this interpretation, we find a strictly linear relation between the open-circuit voltage and the energy of the charge state for such hybrid organicinorganic interfaces.
Y1  - 2015
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/39169
SN  - 1948-7185
VL  - 6
IS  - 3
SP  - 500
EP  - 504
PB  - American Chemical Society
CY  - Washington
ER  -