Optically induced charge separation at the naphthalenediimide–phenothiazine interface

Title data

Trepl, Thomas ; de Assis, Renan G. ; Isborn, Christine M. ; de Queiroz, Thiago B. ; Kümmel, Stephan:
Optically induced charge separation at the naphthalenediimide–phenothiazine interface.
In: Physical Chemistry Chemical Physics. Vol. 27 (2025) . - pp. 24806-24815.
ISSN 1463-9084
DOI: https://doi.org/10.1039/d5cp02934a

Project information

Abstract in another language

Naphthalenediimide (NDI) is stable under ambient air and an efficient electron acceptor due to its high
electron affinity. Phenothiazine derivatives are paradigm electron donors due to their relatively low
oxidation potentials and cations of high stability. Combining these two system classes therefore appears
as a promising strategy for obtaining a material with attractive optoelectronic properties. We here
investigate molecular models of p-coupled junctions of N,N0-bis[3-(triethoxysilyl)propyl]-1,4,5,8-
naphthalenediimide (NDI-silane) and 3,7-di-t-butylphenothiazine (TBP) using time-dependent density
functional theory. We calculate the electronic excitations for systems with frozen nuclei, and in a
second step also investigate the influence that the dynamics of the nuclei has on the electronic
excitations. We find optically active excitations around 1.5 eV that are associated with a charge transfer
at the interface. We further calculate the electronic couplings between the states that are the most
relevant ones for charge separation. Our findings can be seen as indicators for these materials’ suitability
for photovoltaic applications. First experimental results are in line with the theoretical conclusions