Purely organic near-infrared afterglow systems based on a triplet excimer donor

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 12; no. 11; pp. 3924 - 393
• Main Authors: Lin, Faxu, Chen, Jinzheng, Miao, Yiling, Long, Xiang, Wang, Wen, Hu, Wei, Wang, Haiyang, Huang, Huahua, Liang, Guodong, Chi, Zhenguo
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 14.03.2024
• Subjects: Afterglows; Emission; Energy transfer; Excimers; Near infrared radiation; Phosphorescence; Polyvinyl alcohol; Room temperature
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d3tc04708c

An efficient near-infrared (NIR) afterglow emission at over 750 nm is highly valuable for the advanced detection technology. Herein, a new kind of organic NIR afterglow system with persistent emission (0.16 s) at 808 nm is prepared by using a red room temperature phosphorescence (RTP) excimer as a donor and a NIR dye cyanine 7 (Cy7) as an acceptor. In the pyren-1-ylboronic acid@poly(vinyl alcohol) (PYB@PVA) system, its red persistent RTP emission at over 590 nm is proved to be derived from the triplet excimer of PYB. So, the bright NIR afterglow is achieved via only a single triplet-to-singlet Förster-resonance energy transfer process between PYB@PVA and Cy7. Moreover, PYB 2 @PVA with more triplet excimers is beneficial to improve NIR emission intensity with a quantum yield of 1.6%. This work demonstrates that exploiting triplet excimers is meaningful to develop purely organic red or NIR afterglow materials with the emission at a long wavelength. A kind of NIR afterglow with a lifetime of 0.16 s at 808 nm was prepared using triplet excimer (PVB@PVA) as the donor. PYB 2 @PVA containing more excimers is beneficial to improve luminescence of Cy7 acceptor via a triplet-to-singlet energy transfer.