TY  - JOUR
A1  - Kim, Jin Hong
A1  - Liess, Andreas
A1  - Stolte, Matthias
A1  - Krause, Ana-Maria
A1  - Stepanenko, Vladimir
A1  - Zhong, Chuwei
A1  - Bialas, David
A1  - Spano, Frank
A1  - Würthner, Frank
T1  - An Efficient Narrowband Near-Infrared at 1040 nm Organic Photodetector Realized by Intermolecular Charge Transfer Mediated Coupling Based on a Squaraine Dye
JF  - Advanced Materials
N2  - A highly sensitive short-wave infrared (SWIR, λ > 1000 nm) organic photodiode (OPD) is described based on a well-organized nanocrystalline bulk-heterojunction (BHJ) active layer composed of a dicyanovinyl-functionalized squaraine dye (SQ-H) donor material in combination with PC\(_{61}\)BM. Through thermal annealing, dipolar SQ-H chromophores self-assemble in a nanoscale structure with intermolecular charge transfer mediated coupling, resulting in a redshifted and narrow absorption band at 1040 nm as well as enhanced charge carrier mobility. The optimized OPD exhibits an external quantum efficiency (EQE) of 12.3% and a full-width at half-maximum of only 85 nm (815 cm\(^{-1}\)) at 1050 nm under 0 V, which is the first efficient SWIR OPD based on J-type aggregates. Photoplethysmography application for heart-rate monitoring is successfully demonstrated on flexible substrates without applying reverse bias, indicating the potential of OPDs based on short-range coupled dye aggregates for low-power operating wearable applications.
KW  - squaraine dyes
KW  - crystal engineering
KW  - J-aggregates
KW  - near-infrared sensitivity
KW  - organic photodiodes
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256374
VL  - 33
IS  - 26
ER  - 
TY  - JOUR
A1  - Bold, Kevin
A1  - Stolte, Matthias
A1  - Shoyama, Kazutaka
A1  - Krause, Ana‐Maria
A1  - Schmiedel, Alexander
A1  - Holzapfel, Marco
A1  - Lambert, Christoph
A1  - Würthner, Frank
T1  - Macrocyclic Donor‐Acceptor Dyads Composed of Oligothiophene Half‐Cycles and Perylene Bisimides
JF  - Chemistry – A European Journal
N2  - A series of donor‐acceptor (D−A) macrocyclic dyads consisting of an electron‐poor perylene bisimide (PBI) π‐scaffold bridged with electron‐rich α‐oligothiophenes bearing four, five, six and seven thiophene units between the two phenyl‐imide substituents has been synthesized and characterized by steady‐state UV/Vis absorption and fluorescence spectroscopy, cyclic and differential pulse voltammetry as well as transient absorption spectroscopy. Tying the oligothiophene strands in a conformationally fixed macrocyclic arrangement leads to a more rigid π‐scaffold with vibronic fine structure in the respective absorption spectra. Electrochemical analysis disclosed charged state properties in solution which are strongly dependent on the degree of rigidification within the individual macrocycle. Investigation of the excited state dynamics revealed an oligothiophene bridge size‐dependent fast charge transfer process for the macrocyclic dyads upon PBI subunit excitation.
KW  - donor-acceptor dyad
KW  - macrocycle
KW  - oligothiophene
KW  - perylene bisimide
KW  - photoinduced electron transfer
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276435
VL  - 28
IS  - 30
ER  -