Delocalized Nonbonding Orbitals of Thioxanthone in Polycyclic Aromatic Hydrocarbons for Reduced Energy Gap and Narrowband Emission

Zhihai Yang; Denghui Liu; Xiangyi Cheng; Tong Wang; Zhizhi Li; Guo-Xi Yang; Zijian Chen; Juntao Hu; Yu Fu; Xuewei Nie; Yongxia Ren; Yitong Zeng; Yuling Chen; Kunkun Liu; Mengke Li; Shi-Jian Su

doi:10.1002/anie.202423602

Delocalized Nonbonding Orbitals of Thioxanthone in Polycyclic Aromatic Hydrocarbons for Reduced Energy Gap and Narrowband Emission

Angew Chem Int Ed Engl. 2025 Jan 8:e202423602. doi: 10.1002/anie.202423602. Online ahead of print.

Authors

Zhihai Yang¹, Denghui Liu¹, Xiangyi Cheng¹, Tong Wang¹, Zhizhi Li¹, Guo-Xi Yang¹, Zijian Chen¹, Juntao Hu¹, Yu Fu¹, Xuewei Nie¹, Yongxia Ren¹, Yitong Zeng¹, Yuling Chen¹, Kunkun Liu¹, Mengke Li¹, Shi-Jian Su²

Affiliations

¹ South China University of Technology School of Materials Science and Engineering, State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, CHINA.
² South China University of Technology School of Materials Science and Engineering, State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, 381 Wushan Road, 510640, Guangzhou, CHINA.

PMID: 39779478
DOI: 10.1002/anie.202423602

Abstract

Chalcogen-containing carbonyls, specifically thioxanthone (TX), hold great potential in organic light-emitting diodes (OLEDs). While the development of narrowband OLEDs with chalcogen-containing carbonyls remains challenging due to difficulties in achieving both high device efficiency and narrow emission spectra. Herein, via a strategic incorporation of the TX moiety, two orange-red narrowband emitters, 2TXBN and BNTXBN, are designed and synthesized for the first time. Both 2TXBN and BNTXBN exhibit bright orange-red emissions with peaks at 582 and 585 nm, respectively, along with narrow full widths at half maximum of 30 and 32 nm. Notably, 2TXBN demonstrates delocalization of the nonbonding orbital within the TX segment, which raises the first triplet energy level and reduces the singlet-triplet energy gap. This electronic structural adjustment effectively shortens the delayed fluorescence lifetime, leading to enhanced device performance. Accordingly, OLED employing 2TXBN as the emitter achieves remarkable performance, with a maximum external quantum efficiency of 31.0%, a current efficiency of 69.0 cd A-1, and a power efficiency of 76.0 lm W-1, highlighting the efficacy of the nonbonding orbital delocalization strategy in achieving bathochromic-shifted narrowband OLED materials.

Keywords: Chalcogen-containing carbonyls; narrowband emission; organic light-emitting diode; polycyclic aromatic hydrocarbons; thermally activated delayed fluorescence.