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Effect of Slip-Stack Self-Assembly on Aggregation-Induced Emission and Solid-State Luminescence in 1,3-Diarylpropynones
Date Issued
01-04-2019
Author(s)
Sivalingam, Soumya
Debsharma, Kingshuk
Dasgupta, Ayan
Indian Institute of Technology, Madras
Prasad, Edamana
Abstract
Co-facial stacking can result in aggregation-caused quenching (ACQ) in conjugated organic luminogens. This study provides an attractive ‘slip-stack’ self-assembly approach which can eliminate the occurrence of ACQ. The obtained results from steady-state and time-resolved optical studies, along with X-ray diffraction and computational studies demonstrate aggregation-induced emission enhancement (AIEE) of a donor-π-acceptor based 1,3-diarylpropynone, namely 1-(naphthalenyl)-3-(pyren-1-yl)prop-2-yn-1-one (PYNAP). Unlike the monomer, which exhibits poor photoluminescence in solution (φ f =2 % in ACN), the twisted manifold of PYNAP allows the orientation of the molecules in a slip-stack fashion during the course of aggregation, which not only avoids a direct co-facial arrangement, but also induces augmented rigidity, leading to restricted intramolecular rotation (RIR) and enhanced emission quantum yield (φ f =5 % in ACN/H 2 O). The aggregation behavior of PYNAP's congener, 1-phenyl-3-(pyren-1-yl)prop-2-yn-1-one (PYPH) reinforces the hypothesis that slip-stack assembly is a useful strategy for AIEE in polycyclic hydrocarbon luminogens.
Volume
84