New Molecular Design Concurrently Providing Superior Pure Blue, Thermally Activated Delayed Fluorescence and Optical Out-Coupling Efficiencies

P Rajamalli; N Senthilkumar; P-Y Huang; C-C Ren-Wu; H-W Lin; C-H Cheng

doi:10.1021/jacs.7b03848

New Molecular Design Concurrently Providing Superior Pure Blue, Thermally Activated Delayed Fluorescence and Optical Out-Coupling Efficiencies

J Am Chem Soc. 2017 Aug 16;139(32):10948-10951. doi: 10.1021/jacs.7b03848. Epub 2017 Aug 2.

Authors

P Rajamalli¹, N Senthilkumar¹, P-Y Huang¹, C-C Ren-Wu¹, H-W Lin¹, C-H Cheng¹

Affiliation

¹ Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan.

PMID: 28745874
DOI: 10.1021/jacs.7b03848

Abstract

Simultaneous enhancement of out-coupling efficiency, internal quantum efficiency, and color purity in thermally activated delayed fluorescence (TADF) emitters is highly desired for the practical application of these materials. We designed and synthesized two isomeric TADF emitters, 2DPyM-mDTC and 3DPyM-pDTC, based on di(pyridinyl)methanone (DPyM) cores as the new electron-accepting units and di(tert-butyl)carbazole (DTC) as the electron-donating units. 3DPyM-pDTC, which is structurally nearly planar with a very small ΔE_ST, shows higher color purity, horizontal ratio, and quantum yield than 2DPyM-mDTC, which has a more flexible structure. An electroluminescence device based on 3DPyM-pDTC as the dopant emitter can reach an extremely high external quantum efficiency of 31.9% with a pure blue emission. This work also demonstrates a way to design materials with a high portion of horizontal molecular orientation to realize a highly efficient pure-blue device based on TADF emitters.

Publication types

Research Support, Non-U.S. Gov't