Achieving highly efficient long-wavelength phosphorescence emission of large singlet-triplet energy gap materials by host-guest doping

• Published in: Science China. Chemistry Vol. 67; no. 6; pp. 1922 - 1928
• Main Authors: Zhang, Shasha, Yao, Wei, Lv, Anqi, Liu, Kun, Zhang, Yusheng, Zhou, Chifeng, Ma, Huili, Shi, Huifang, An, Zhongfu
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 2024; Springer Nature B.V
• Subjects: Atomic energy levels; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Communications; Crystals; Data encryption; Efficiency; Emission; Energy; Energy gap; Excitons; Host-guest materials; Lifetime; Luminescence quenching; Phosphorescence; Quantum efficiency; Room temperature; Spin-orbit interactions; Temperature; singlet-triplet energy gap; heavy atom effect; room temperature phosphorescence; host-guest doping; red phosphorescence
• ISSN: 1674-7291; 1869-1870
• DOI: 10.1007/s11426-023-1935-y

High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap (Δ E ST ) materials are essential for applications in biology and display. However, few long-wavelength phosphorescence emissions of large Δ E ST materials have been reported due to the weak spin-orbit coupling (SOC) and strong non-radiative transitions. Herein, we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence (RTP) emission of large Δ E ST materials, which display bright red RTP emission with above 400 µs lifetime and 6.5% phosphorescent quantum efficiency. Our experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons, and heavy atoms effectively promote the intersystem crossing (ISC) process for highly efficient long-wavelength phosphorescence emission. The universality of the method for highly efficient long-wavelength RTP emission of large Δ E ST materials was further investigated in various guests. Moreover, these materials with large Δ E ST manifest the advantages of large color contrast on the display and utilization potentiality in information encryption. This strategy paves the way for the high contrast display and development of information encryption with RTP emission.