Exploiting racemism enhanced organic room-temperature phosphorescence to demonstrate Wallach’s rule in the lighting chiral chromophores

Xiugang Wu, Chun Ying Huang, Deng Gao Chen, Denghui Liu, Chichi Wu, Keh Jiunh Chou, Bin Zhang, Yafei Wang, Yu Liu, Elise Y. Li, Weiguo Zhu, Pi Tai Chou

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Abstract

The correlation between molecular packing structure and its room-temperature phosphorescence (RTP), hence rational promotion of the intensity, remains unclear. We herein present racemism enhanced RTP chiral chromophores by 2,2-bis-(diphenylphosphino)-1,1-napthalene (rac-BINAP) in comparison to its chiral counterparts. The result shows that rac-BINAP in crystal with denser density, consistent with a long standing Wallach’s rule, exhibits deeper red RTP at 680 nm than that of the chiral counterparts. The cross packing between alternative R- and S- forms in rac-BINAP crystal significantly retards the bimolecular quenching pathway, triplet-triplet annihilation (TTA), and hence suppresses the non-radiative pathway, boosting the RTP intensity. The result extends the Wallach’s rule to the fundamental difference in chiral-photophysics. In electroluminescence, rac-BINAP exhibits more balanced fluorescence versus phosphorescence intensity by comparison with that of photoluminescence, rendering a white-light emission. The result paves an avenue en route for white-light organic light emitting diodes via full exploitation of intrinsic fluorescence and phosphorescence.

Original languageEnglish
Article number2145
JournalNature Communications
Volume11
Issue number1
DOIs
Publication statusPublished - 2020 Dec 1

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Wu, X., Huang, C. Y., Chen, D. G., Liu, D., Wu, C., Chou, K. J., Zhang, B., Wang, Y., Liu, Y., Li, E. Y., Zhu, W., & Chou, P. T. (2020). Exploiting racemism enhanced organic room-temperature phosphorescence to demonstrate Wallach’s rule in the lighting chiral chromophores. Nature Communications, 11(1), [2145]. https://doi.org/10.1038/s41467-020-15976-5