Physics

OLED

Nanotechnology

Dipole

Organic chemistry

Quantum efficiency

Electrical efficiency

Optics

Excited state

Atomic physics

Power (physics)

Chemistry

Materials science

Pyridine

Layer (electronics)

Singlet state

Quantum mechanics

Diode

Photoluminescence

Optoelectronics

Intersystem crossing

Photochemistry

Fluorescence

Advanced Materials

Highly efficient thermally activated delayed fluorescence (TADF) molecules are in urgent demand for solid‐state lighting and full‐color displays. Here, the design and synthesis of three triarylamine‐pyridine‐carbonitrile‐based TADF compounds, TPAPPC, TPAmPPC, and tTPAmPPC, are shown. They exhibit excellent photoluminescence quantum yields of 79−100% with small Δ E ST values, fast reverse intersystem crossing (RISC), and high horizontal dipole ratios (Θ // = 86−88%) in the thin films leading to the enhancement of device light outcoupling. Consequently, a green organic light‐emitting diode (OLED) based on TPAmPPC shows a high average external quantum efficiency of 38.8 ± 0.6%, a current efficiency of 130.1 ± 2.1 cd A –1 , and a power efficiency of 136.3 ± 2.2 lm W –1 . The highest device efficiency of 39.8% appears to be record‐breaking among TADF‐based OLEDs to date. In addition, the TPAmPPC‐based device shows superior operation lifetime and high‐temperature resistance. It is worth noting that the TPA‐PPC‐based materials have excellent optical properties and the potential for making them strong candidates for TADF practical application.

Triarylamine‐Pyridine‐Carbonitriles for Organic Light‐Emitting Devices with EQE Nearly 40%