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  - 
TY  - JOUR
A1  - Stolte, Matthias
A1  - Hecht, Reinhard
A1  - Xie, Zengqi
A1  - Liu, Linlin
A1  - Kaufmann, Christina
A1  - Kudzus, Astrid
A1  - Schmidt, David
A1  - Würthner, Frank
T1  - Crystal Engineering of 1D Exciton Systems Composed of Single‐ and Double‐Stranded Perylene Bisimide J‐Aggregates
JF  - Advanced Optical Materials
N2  - Single crystals of three at bay area tetraphenoxy‐substituted perylene bisimide dyes are grown by vacuum sublimation. X‐ray analysis reveals the self‐assembly of these highly twisted perylene bisimides (PBIs) in the solid state via imide–imide hydrogen bonding into hydrogen‐bonded PBI chains. The crystallographic insights disclose that the conformation and sterical congestion imparted by the phenoxy substituents can be controlled by ortho‐substituents. Accordingly, whilst sterically less demanding methyl and isopropyl substituents afford double‐stranded PBI chains of complementary P and M atropo‐enantiomers, single hydrogen‐bonded chains of homochiral PBIs are observed for the sterically more demanding ortho‐phenyl substituents. Investigation of the absorption and fluorescence properties of microcrystals and thin films of these PBIs allow for an unambiguous interpretation of these exciton systems. Thus, the J‐aggregates of the double‐stranded crystals exhibit a much larger (negative) exciton coupling than the single‐stranded one, which in contrast has the higher solid‐state fluorescence quantum yield.
KW  - fluorescence
KW  - J‐aggregates
KW  - perylene bisimides
KW  - reabsorption
KW  - single crystal structure
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218221
VL  - 8
IS  - 18
ER  -