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Pyridal[2,1,3]thiadiazole as strong electron-withdrawing and less sterically-hindered acceptor for highly efficient donor–acceptor type NIR materials
- Source :
- Journal of Materials Chemistry C. 5:11053-11058
- Publication Year :
- 2017
- Publisher :
- Royal Society of Chemistry (RSC), 2017.
-
Abstract
- Pyridal[2,1,3]thiadiazole (PT) is an analogue of benzo[1,2,5]thiadiazole (BT), which is a common acceptor in charge transfer (CT) chromophores. Compared with BT, PT is more electron-deficient and less sterically hindered. Herein we demonstrate the effect of using PT as proto-acceptor in the design of D–A type NIR emitting materials. The compound p-TPA-PT-CN was synthesized, which combines PT with the donor triphenylamine (TPA) and cyano-substituent (CN), and shows NIR emission at ∼700 nm with a high PL efficiency of 0.3 in both solution and solid state. The strong D–A interaction within p-TPA-PT-CN results in a low energy charge-transfer state. The pyridine nitrogen of PT reduces the steric hindrance between PT and the adjacent TPA donor segment, resulting in increased planarity and strong mixing (hybridization) of CT and π–π states (HLCT). Such strong mixing contributes towards a higher luminous efficiency. The OLEDs fabricated with p-TPA-PT-CN as the emitting layer exhibited an EQE of 1.47% and Lmax = 640 cd m−2, which are amongst the highest values reported for NIR-OLED devices.
- Subjects :
- Steric effects
Materials science
02 engineering and technology
General Chemistry
Chromophore
010402 general chemistry
021001 nanoscience & nanotechnology
Triphenylamine
Photochemistry
01 natural sciences
Acceptor
0104 chemical sciences
chemistry.chemical_compound
chemistry
Pyridine
Materials Chemistry
Polar effect
OLED
0210 nano-technology
Luminous efficacy
Subjects
Details
- ISSN :
- 20507534 and 20507526
- Volume :
- 5
- Database :
- OpenAIRE
- Journal :
- Journal of Materials Chemistry C
- Accession number :
- edsair.doi...........0431c37e0fa53101e9e0dfd46f664b4a