Efficient Near-Infrared Electroluminescence at 840 nm with “Metal-Free” Small-Molecule:Polymer Blends
Journal article, 2018

Due to the so-called energy-gap law and aggregation quenching, the efficiency of organic light-emitting diodes (OLEDs) emitting above 800 nm is significantly lower than that of visible ones. Successful exploitation of triplet emission in phosphorescent materials containing heavy metals has been reported, with OLEDs achieving remarkable external quantum efficiencies (EQEs) up to 3.8% (peak wavelength > 800 nm). For OLEDs incorporating fluorescent materials free from heavy or toxic metals, however, we are not aware of any report of EQEs over 1% (again for emission peaking at wavelengths > 800 nm), even for devices leveraging thermally activated delayed fluorescence (TADF). Here, the development of polymer light-emitting diodes (PLEDs) peaking at 840 nm and exhibiting unprecedented EQEs (in excess of 1.15%) and turn-on voltages as low as 1.7 V is reported. These incorporate a novel triazolobenzothiadiazole-based emitter and a novel indacenodithiophene-based transport polymer matrix, affording excellent spectral and transport properties. To the best of knowledge, such values are the best ever reported for electroluminescence at 840 nm with a purely organic and solution-processed active layer, not leveraging triplet-assisted emission.

indacenodithiophene

near-infrared

blends

organic light-emitting diodes (OLEDs)

triazolobenzothiadiazole

Author

Alessandro Minotto

University College London (UCL)

Petri Henrik Murto

Flinders University

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Zewdneh Genene

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Addis Ababa University

Andrea Zampetti

University College London (UCL)

Giuseppe Carnicella

University College London (UCL)

Wendimagegn Mammo

Addis Ababa University

Mats Andersson

Flinders University

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Ergang Wang Group

Franco Cacialli

University College London (UCL)

Advanced Materials

09359648 (ISSN) 15214095 (eISSN)

Vol. 30 34 1706584

Organic Semiconductors for NIR Optoelectronics (OSNIRO)

European Commission (FP7), 2013-10-01 -- 2017-09-30.

Subject Categories

Polymer Chemistry

Other Chemistry Topics

Condensed Matter Physics

DOI

10.1002/adma.201706584

More information

Latest update

4/3/2019 2