Despite the success of thermally activated delayed fluorescent (TADF) materials in steering the next generation of organic light-emitting diodes (OLEDs), effective near infrared (NIR) TADF emitters are still very rare. Here, we present a simple and extremely high electron-deficient compound, 5,6dicyano[2,1,3]benzothiadiazole (CNBz), as a strong electronaccepting unit to develop a sufficiently strong donor-acceptor (DÀ A) interaction for NIR emission. End-capping with the electron-donating triphenylamine (TPA) unit created an effective DÀ AÀ D type system, giving rise to an efficient NIR TADF emissive molecule (λ em = 750 nm) with a very small ΔE ST of 0.06 eV. The electroluminescent device using this NIR TADF emitter exhibited an excellent performance with a high maximum radiance of 10020 mW Sr À 1 m À 2 , a maximum EQE of 6.57% and a peak wavelength of 712 nm.

Triplet–triplet annihilation (TTA) mechanism utilizing the conversion of low triplet energy excitons to generate singlet excitons has been successfully employed in realizing highly efficient fluorescent organic light‐emitting diodes (OLEDs). Herein, new anthracene‐based TTA molecules (TPNACN and TPBACN) are developed as deep‐blue emitters for high‐efficiency non‐doped TTA‐OLEDs. Their structural, physical, and photophysical properties are experimentally and theoretically investigated. These compounds in solid‐state exhibit different photophysical properties due to a discrepancy in the molecular packing. Particularly, in the crystal of TPNACN, anthracene moieties are arranged with dimeric π–π stacking, and the material shows a strong excimer emission in the deep‐blue region with ΦPL close to the ideal theoretical value. The non‐doped TTA‐OLED based on TPNACN attains a high maximum external quantum efficiency of 7.89% (6.63 cd A−1) with a low turn‐on voltage of 2.6 V, and displays deep‐blue emission with CIE coordinates of (0.146, 0.101). These results prove that a separated dimeric π‐stacked molecular alignment of anthracene enhances not only the fluorescence efficiency in the solid state but also the ratio of singlet exciton harvested by the TTA process in the device, bringing about excellent device electroluminescent properties. This can be a new tactic to designing new emissive materials for efficient OLED devices.

Two D–A–D type emitters exhibited superior simple hole-transporting free solution-processed OLEDs with maximum EQE of 1.52%, low efficiency roll-off and maximum radiance of 4463 mW Sr−1 m−2, which is one the best solution-processed NIR-OLEDs.

The hybridized local and charge-transfer (HLCT) excited state is a successful approach to accomplish both high external and internal quantum efficiency. To attain deep blue emissive HLCT emitters, two cyanophenyl...

New triphenylethylene-phenanthrocarbazole (PCTrPE) was the first small molecule that exhibited dual fluorescence emission in the solid state providing a new strategy to realize a single-molecule white emissive material for white OLEDs.