Aggregates a constructive and functional molecular assembly as potential photonic material

Abstract

Light and light emitting materials remain captivating both in everyday life newlineand in the realms of science and technology. Luminescent materials find a newlinewide array of applications in photonics, including optoelectronic devices, newlinebiomedical imaging, sensors, displays, and more. Despite the anticipation newlinefor these materials to perform proficiently in liquid and solid state, a newlinesignificant proportion of luminophores are predominantly utilized at newlineindustries in solid state. However, fluorescence of most luminophores are newlineweakened or completely quenched in solutions at higher concentrations or newlinein solid state because of molecular aggregation. Notably, a major newlinedrawback is that many conventional luminophores experience emission newlinequenching, either partially or entirely, when transitioning into an newlineaggregate state compared to their behaviour in a dilute solution. newlineaggregation caused quenching (ACQ) is a notorious photophysical newlinephenomenon that mainly occurs in aromatic molecules, rendering them newlineunsuitable for the fabrication of solid-state devices and for applications newlinethat rely on concentration-dependent sensing. Aggregation induced newlineemission (AIE) is an interesting photophysical phenomenon, first coined newlineby B. Z. Tang in 2001. This phenomenon is associated with chromophore newlineaggregation and can be described as a process in which a non-emissive newlinemolecule in solution state is induced to emit upon aggregation which is newlineexactly an opposite effect of ACQ. In this thesis, systematic newlineinvestigations on AIE effect of selected organic molecules were newlineii newlineperformed and also explored their AIE property for versatile photonic newlineapplications like nonlinear optics (NLO), FRET assisted chemosensing, newlinewhite light emission (WLE), etc. newline