Recently, conjugated donor-acceptor (D-A) based organic fluorophores have been emerged as an attractive class of molecules with unique photophysical characteristics suitable for wide range of applications in optoelectronics, sensing and stimuli responsive devices fabrication.1,2 The processing and applicability of such molecular systems exclusively depend upon the judicious selection of fluorophores, allowing pivotal modulations of both electronic and optoelectronic properties, which are prerequisite to make the resultant conjugates emissive in aggregated/solid state. Rigid, planar and polycyclic fluorophores are usual candidates for fluorescent based studies because they are highly emissive in dilute solutions. However, their luminescence efficiency is greatly suppressed in concentrated solutions or in solid state due to spontaneous aggregation where severe face-to-face arrangement amongst the molecules induces delocalization of electrons which ultimately leads to the thorny effect of aggregation caused quenching (ACQ).1 This damaging effect seriously limits the practical applications of π-conjugated organic luminogens as any optoelectronics and sensing device necessitates organic fluorophores in aggregated and/or solid state where ACQ is unavoidable. Therefore one of the ways to overcome ACQ is to prepare self-assembled systems which exhibit aggregation and/or gelation-induced enhanced emission (AIE and/or GIE) with high solid state luminescence, through restricted intramolecular rotation (RIR) mechanism.2,3
The colloquium will provide a detailed description of the design, synthesis and photophysical characteristics of the developed novel AIE/GIE-based multifunctional fluorophores from our laboratory, which induce ACQ-to-AIE transformation through a unique self-assembly strategy.4 In addition, AIE/GIE based real-world applications of the developed molecular systems in dual-sensing of acid/amine, developing mechano-fluorochromic materials with isotropic/anisotropic pressures as well as sensing of cyanide from water along with fabrication of hydrophobic surface with excellent water repellence property will be explained.
References
1. J. Mei, N. L. Leung, R. T. Kwok, J. W. Lam, B. Z. Tang, Chem. Rev. 2015, 115, 11718-11940.
2. B. K. An, J. Gierschner, S. Y. Park, Acc. Chem. Res. 2012, 45, 544-554.
3. Y. Hong, J. W. Lam, B. Z. Tang, Chem. Commun. 2009, 4332-4353.
4. (a) K. Debsharma, J. Santhi, B. Baire, E. Prasad, ACS Appl. Mater. Interfaces 2019, 11, 48249-48260; (b) K. Debsharma, S. Sivalingam, A. Dasgupta, S. Sankararaman, E. Prasad, ChemPlusChem 2019, 84, 392-402.