TY  - JOUR
A1  - Dietzsch, Julia
A1  - Bialas, David
A1  - Bandorf, Johannes
A1  - Würthner, Frank
A1  - Höbartner, Claudia
T1  - Tuning Exciton Coupling of Merocyanine Nucleoside Dimers by RNA, DNA and GNA Double Helix Conformations
JF  - Angewandte Chemie International Edition
N2  - Exciton coupling between two or more chromophores in a specific environment is a key mechanism associated with color tuning and modulation of absorption energies. This concept is well exemplified by natural photosynthetic proteins, and can also be achieved in synthetic nucleic acid nanostructures. Here we report the coupling of barbituric acid merocyanine (BAM) nucleoside analogues and show that exciton coupling can be tuned by the double helix conformation. BAM is a nucleobase mimic that was incorporated in the phosphodiester backbone of RNA, DNA and GNA oligonucleotides. Duplexes with different backbone constitutions and geometries afforded different mutual dye arrangements, leading to distinct optical signatures due to competing modes of chromophore organization via electrostatic, dipolar, - stacking and hydrogen-bonding interactions. The realized supramolecular motifs include hydrogenbonded BAM–adenine base pairs and antiparallel as well as rotationally stacked BAM dimer aggregates with distinct absorption, CD and fluorescence properties.
KW  - Chromophore Assembly
KW  - Merocyanine
KW  - Nucleobase Analogue
KW  - Supramolecular Element
KW  - Nucleic Acids
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254565
ER  - 
TY  - JOUR
A1  - Kim, Jin Hong
A1  - Schembri, Tim
A1  - Bialas, David
A1  - Stolte, Matthias
A1  - Würthner, Frank
T1  - Slip‐Stacked J‐Aggregate Materials for Organic Solar Cells and Photodetectors
BT  - This paper is dedicated to Prof. Daoben Zhu on the occasion of his 80th birthday
JF  - Advanced Materials
N2  - Dye–dye interactions affect the optical and electronic properties in organic semiconductor films of light harvesting and detecting optoelectronic applications. This review elaborates how to tailor these properties of organic semiconductors for organic solar cells (OSCs) and organic photodiodes (OPDs). While these devices rely on similar materials, the demands for their optical properties are rather different, the former requiring a broad absorption spectrum spanning from the UV over visible up to the near‐infrared region and the latter an ultra‐narrow absorption spectrum at a specific, targeted wavelength. In order to design organic semiconductors satisfying these demands, fundamental insights on the relationship of optical properties are provided depending on molecular packing arrangement and the resultant electronic coupling thereof. Based on recent advancements in the theoretical understanding of intermolecular interactions between slip‐stacked dyes, distinguishing classical J‐aggregates with predominant long‐range Coulomb coupling from charge transfer (CT)‐mediated or ‐coupled J‐aggregates, whose red‐shifts are primarily governed by short‐range orbital interactions, is suggested. Within this framework, the relationship between aggregate structure and functional properties of representative classes of dye aggregates is analyzed for the most advanced OSCs and wavelength‐selective OPDs, providing important insights into the rational design of thin‐film optoelectronic materials.
KW  - crystal engineering
KW  - exciton coupling
KW  - J‐aggregates
KW  - organic photodiodes
KW  - organic solar cells
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276537
VL  - 34
IS  - 22
ER  -