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Piezochromism of Cruciform‐Shaped Luminophores: Suitable Molecular Design to Enhance Colour Difference and Sensitivity
Author(s) -
Wang Bin,
Wang Kai,
Wei ChunYing
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202000566
Subject(s) - cruciform , diphenylamine , materials science , excited state , benzocyclobutene , dihedral angle , photoluminescence , fluorescence , optoelectronics , photochemistry , molecule , chemistry , optics , organic chemistry , nuclear physics , dielectric , metallurgy , composite material , hydrogen bond , physics
Two cruciform‐shaped piezochromic materials, PBM‐DPA and PBM‐BCbz , have been developed. PBM‐DPA exhibits a higher photoluminescence quantum yields (PLQY) and redder emission than PBM‐BCbz owing to the formation of a hybridized local and charge‐transfer (HLCT) excited state. Furthermore, high‐pressure measurements indicate that PBM‐DPA displays a higher sensitivity (9.4 nm/GPa) than PBM‐BCbz (6.4 nm/GPa) under the same pressure range. Information from the crystal structures suggests that this is because of the easier planarization of diphenylamine (DPA) in PBM‐DPA . In contrast, PBM‐BCbz possesses a twisty conformation, owing to the large dihedral between the central benzene ring and carbazole (Cbz), which hinders the coplanarization of the whole PBM‐BCbz molecule. This phenomenon reveals that molecular structure can efficiently influence piezochromic contrast and sensitivity. Both the planarization and the HLCT excited‐state characteristics make PBM‐DPA a high‐performance piezochromic material. This research will help to design high‐performance pressure‐response materials.