Highly efficient deep-red TADF organic light-emitting diodes via increasing the acceptor strength of fused polycyclic aromatics

Molecular Design Strategy for Orange Red Thermally Activated Delayed Fluorescence Emitters in Organic Light‐Emitting Diodes (OLEDs)

“…A similar approach was adopted by Liao et al in 2021 by substituting electron-deficient pyridinyl (PY), trifluoromethyl (CF 3 ), and cyano (CN) moieties at ortho position to rigid cyano fused phenazine acceptor with triphenylamine donor. [30] Three emitters, PY-TPA, CF3-TPA, and CN-TPA, showed similar TADF performance and high PLQY of over 88 %. When the LUMO level got deeper, the emission wavelength shifted dramatically towards the red region due to the narrow bandgap.…”

NIR TADF emitters and OLEDs: challenges, progress, and perspectives

“…Devices based on CN-TPA exhibited a leading EQE max of 18.41% at 688 nm and 15.05% at 698 nm. 51 This work provided new insights on the design of efficient NIR TADF emitters.…”

“…Within this range, the near-infrared (NIR) region typically spans from the longest wavelength of red light (680 nm) to 2500 nm. 1 In recent years, NIR materials have attracted great attention in organic light-emitting diodes (OLEDs), 2,3 solar cells, 4–6 bioimaging, 7–10 information storage, 11,12 and phototherapy devices. 13 As one of the most important applications of NIR luminescent materials, NIR OLEDs play important roles not only in the fields of night-vision devices, optical communication and information-secured displays, but also in the fields of flat panel displays and lighting fixtures.…”

An extended π-backbone for highly efficient near-infrared thermally activated delayed fluorescence with enhanced horizontal molecular orientation

“…4,5-Diamino-4′-(bis(4-( tert -butyl)phenyl)amino)-[1,1′-biphenyl]-2-carbonitrile was prepared according to the literature method. 13 The acid-catalyzed condensation reaction between the precursor diamine and 1,10-phenanthroline-5,6-dione yielded the dipyrido[3,2- a :2′,3′- c ]phenazine derivatives (1 and TPA-CN-N4). The further Suzuki–Miyaura coupling reaction between dibromide (1) and 3-pyridylboronic acid in toluene/ethanol/water finished the synthesis of TPA-CN-N4-2PY at a high yield of 71.4%.…”