Theoretical design and performance prediction of deep red/near-infrared thermally activated delayed fluorescence molecules with through space charge transfer

• Published in: Physical chemistry chemical physics : PCCP 2024-02, Vol.26 (9), p.776-7717
• Main Authors: Li, Xiaofang, Wang, Xiaofei, Wu, Zhimin, Zhang, Kai, Li, Rui, Song, Yuzhi, Fan, Jianzhong, Wang, Chuan-Kui, Lin, Lili
• Format: Article
• Language: English
• Subjects: Charge transfer; Coupling (molecular); Doppler effect; Emission analysis; Emitters; First principles; Fluorescence; Mathematical analysis; Near infrared radiation; Performance prediction; Red shift; Space charge; Spin-orbit interactions
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp05670h

Thermally activated delayed fluorescence (TADF) molecules with through-space charge transfer (TSCT) have attracted much attention in recent years because of their ability to simultaneously reduce the energy difference (Δ E ST ) and enlarge the spin-orbit coupling (SOC). In this paper, 40 molecules are theoretically designed by changing the different substitution positions of the donors and acceptors, and systematically investigated based on the first-principles calculations and excited-state dynamics study. It is found that the emission wavelengths of v-shaped molecules with intramolecular TSCT are larger than those of the molecules without TSCT. Therefore, the intramolecular TSCT can induce the red-shift of the emission and realize the deep-red/near-infrared emission. Besides intramolecular TSCT can simultaneously increase the SOC as well as the oscillator strength and reduce the Δ E ST . In addition, PXZ or PTZ can also favor the realization of smaller Δ E ST and red-shift emission. Our calculations suggest that intramolecular TSCT and suitable donors (-PXZ or -PTZ) are an effective strategy for the design of efficient deep red/near-infrared TADF emitters. Thermally activated delayed fluorescence (TADF) molecules with through-space charge transfer (TSCT) simultaneously reduce the energy difference (Δ E ST ) and enlarge the spin-orbit coupling (SOC).