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

Yi-Kuan Chen; Jayachandran Jayakumar; Chia-Min Hsieh; Tien-Lin Wu; Chun-Cheng Liao; Jayabalan Pandidurai; Chang-Lun Ko; Wen-Yi Hung; Chien-Hong Cheng

doi:10.1002/adma.202008032

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

Adv Mater. 2021 Sep;33(35):e2008032. doi: 10.1002/adma.202008032. Epub 2021 Jul 23.

Authors

Affiliations

¹ Department of Chemistry, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Rd., Hsinchu, 30013, Taiwan.
² Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
³ Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung, 20224, Taiwan.
⁴ Department of Chemistry, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.

PMID: 34297444
DOI: 10.1002/adma.202008032

Abstract

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 ΔE_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.

Keywords: external quantum efficiency of nearly 40%; molecular orientation; operational stability; organic light-emitting diodes; pyridine-carbonitrile; thermally activated delayed fluorescence; triphenylamine.