White Light Emitting Polymers from a Luminogen with Local Polarity Induced Enhanced Emission

Abstract

Aggregation induced enhanced emission (AIEE) is considered as an important tool to circumvent the aggregation caused quenching (ACQ) effect in organic light emitting diodes (OLEDs). Charge trapping and surplus long wavelength electroluminescence is a cause of concern in single polymer based white OLEDs. However, the potential of luminogens with AIEE property as a credible tool to offset the above problems in white light emitting single polymer is not properly explored. In this study design, synthesis and spectral characterization of a polymerizable luminogen, (2Z,2′Z)-6,6′-(2,7dibromo-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl)bis(2-cyano-3-(10-hexyl-10H-phenothiazin-3-yl)acrylate(FCPA) with AIEE property and its copolymers is presented. Lippert-Mataga studies showed that reduced local polarity caused by aliphatic chains in condensed state of FCPA resulted in AIEE property. The copolymers P(FCPA-1) and P(FCPA-0.5) with 1% and 0.5% FCPA moieties showed white electroluminescence and enhanced thin film photoluminescence that matched very closely. The superior performance of OLEDs is attributed to the presence of a phenothiazine group in FCPA that resulted in nearly equal electron and hole injection barriers.

Effect of Slip‐Stack Self‐Assembly on Aggregation‐Induced Emission and Solid‐State Luminescence in 1,3‐Diarylpropynones

“…Upon aggregation, significant enhancement of fluorescence lifetime was observed where the obtained lifetimes at maximum f w (%) (τ 1 =2.66 ns, τ 2 =8.86 ns for ACN/H 2 O mixture and τ 1 =1.89 ns, τ 2 =7.23 ns for THF/H 2 O, Table S8) were found to be sufficiently higher compared to the monomer lifetime. This enhancement undoubtedly indicates the lower k nr of PYNAP in aggregated state compared to that in monomeric state (Table S7), endorsing the better luminogenic behavior ,. Corresponding fluorescence decay profiles at higher f w (%) were fitted biexponentially.…”

Anthracene-Resorcinol Derived Covalent Organic Framework as Flexible White Light Emitter

“…Developing white light emitters from single-source fluorophores can contribute immensely to solid-state lighting devices and displays. Current literature indicates that white light emission can be obtained from small conjugated organic molecules, − from composite heterostructures such as hybrid GaN/organic-small-molecule via aggregation-induced emission, from inorganic–organic compounds such as lead halide perovskites, − and from simple metal–organic complexes, , and more pertinently, from amorphous organic polymers via donor–acceptor assemblies, by encapsulating optically active quantum dots, , by mixing blue–green–red light-emitting organic polymers, − and by implanting organic dyes into porous matrices . The recently reported COF-based near-white light emitter is limited by inadequacies in engineering them into membranes …”

Photophysical Characteristics of Polarity‐Sensitive and Lipid Droplet‐Specific Phenylbenzothiadiazoles

“…Steady increase in fluorescence intensity (up to ca . 40 % f w ) is characteristic of aggregation‐induced enhanced emission (AIEE) [23] and subsequent decrease in intensity is consistent with polarity‐induced quenching [11g,11,23a–e] . From f w =60 %, the latter effect overcomes the AIEE and suppresses the emission.…”