Diboron-Based Delayed Fluorescent Emitters with Orange-to-Red Emission and Superior Organic Light-Emitting Diode Efficiency

Chia-Min Hsieh; Tien-Lin Wu; Jayachandran Jayakumar; Ying-Chun Wang; Chang-Lun Ko; Wen-Yi Hung; Tzu-Chieh Lin; Hsin-Hui Wu; Kuan-Heng Lin; Cheng-Hung Lin; Shuchen Hsieh; Chien-Hong Cheng

doi:10.1021/acsami.0c03711

Diboron-Based Delayed Fluorescent Emitters with Orange-to-Red Emission and Superior Organic Light-Emitting Diode Efficiency

ACS Appl Mater Interfaces. 2020 May 20;12(20):23199-23206. doi: 10.1021/acsami.0c03711. Epub 2020 May 7.

Authors

Chia-Min Hsieh¹, Tien-Lin Wu^{1

2}, Jayachandran Jayakumar¹, Ying-Chun Wang¹, Chang-Lun Ko³, Wen-Yi Hung³, Tzu-Chieh Lin⁴, Hsin-Hui Wu⁴, Kuan-Heng Lin⁴, Cheng-Hung Lin⁴, Shuchen Hsieh^{5

6}, Chien-Hong Cheng^{1

5}

Affiliations

¹ Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
² Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
³ Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 20224, Taiwan.
⁴ AU Optronics Corporation, Hsinchu 30078, Taiwan.
⁵ Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
⁶ Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.

PMID: 32326694
DOI: 10.1021/acsami.0c03711

Abstract

For the application of organic light-emitting diodes (OLEDs) in lighting and panels, the basic requirement is to include a full spectrum color range. Compared with the development of blue and green luminophores in thermally activated delayed fluorescence (TADF) technology, the progress of orange-to-red materials is slow and needs further investigation. In this study, three diboron compound-based materials, dPhADBA, dmAcDBA, and SpAcDBA, were designed and synthesized by nucleophilic arylation of three amine donors on 9,10-diboraanthracene (DBA) in a two-step reaction. With increasing electron-donating ability, they show orange-to-red emission with TADF characteristics. The electroluminescence of these diboron compounds exhibits emissions λ_max at 613, 583, and 567 nm for dPhADBA, dmAcDBA, and SpAcDBA, respectively. It is noteworthy that the rod-like D-A-D structures can achieve high horizontal ratios (84-86%) and outstanding device performance for orange-to-red TADF OLEDs: the highest external quantum efficiencies for dPhADBA, dmAcDBA, and SpAcDBA are 11.1 ± 0.5, 24.9 ± 0.5, and 30.0 ± 0.8%, respectively. Therefore, these diboron-based molecules offer a promising avenue for the design of orange-to-red TADF emitters and the development of highly efficient orange-to-red OLEDs.

Keywords: 9,10-diboraanthracene; diboron compound; horizontal dipole ratio; orange-red color; organic light-emitting diode; thermally activated delayed fluorescence.