Highly efficient TADF molecules are in urgent demand for solid-state lighting and full-color displays.[1] Here, the design and synthesis of three triarylamine-pyridine-carbonitrile-based TADF compounds TPAPPC, TPAmPPC, and tTPAmPPC were shown.[2] They exhibited excellent photoluminescence quantum yields of 79~100% with small △EST values, fast reverse intersystem crossing, and high horizontal dipole ratios (θ// = 86~88%) in thin films leading to the enhancement of device light outcoupling.[3] Consequently, a green OLED based on TPAmPPC showed a high average EQE 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 record-breaking among TADF-based OLEDs to date.[4] In addition, the TPAmPPC-based device showed 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 it a strong candidate for TADF practical application.

Reference

1. H. Nakanotani ,* Y. Tsuchiya, C. Adachi* Chem. Lett. 2021, 50, 938.

2. Y.-K. Chen, J. Jayakumar, C.-M. Hsieh, T.-L. Wu, C.-C. Liao, J. Pandidurai, C.-L. Ko, W.-Y. Hung, C.-H. Cheng* Adv. Mater. 2021, 33, 2008032.

3. K.-H. Kim, J.-J. Kim, Adv. Mater. 2018, 1705600.

4. (a) S. S. Kothavale, J. Y. Lee* Adv. Opt. Mater. 2020, 8, 2000922; (b) Y. Liu, C. Li, Z. Ren*, S. Yan* M. R. Bryce* Nat. Rev. Mater. 2018, 3, 18020.