Time-Resolved Fluorescence Study of Aggregation-Induced Emission Enhancement by Restriction of Intramolecular Charge Transfer State

Abstract

Cyano-substituted oligo (alpha-phenylenevinylene)-1,4-bis(R-cyano-4-diphenylaminostyryl)-2,5-diphenylbenzene (CNDPASDB) molecules are studied in solution and aggregate state by time-resolved fluorescence techniques. CNDPASDB exhibits a strong solvent polarity dependent characteristic of aggregation-induced emission (AIE). By time-dependent spectra, the gradual transition from local excited state to intramolecular charge transfer state with the increasing solvent polarity is clearly resolved. The transition time in high polarity solvent DMF is very fast, around 0.5 ps, resulting in a low fluorescence quantum yield. While in aggregate state, the intramolecular torsion is restricted and the local environment becomes less polar. Thus, the intramolecular charge transfer state is eliminated and efficient AIE occurs.

Design and synthesis of theranostic antibiotic nanodrugs that display enhanced antibacterial activity and luminescence

“…2D). These observations are consistent with many other AIE-active luminogens having donor-acceptor structures (21,22,37,(39)(40)(41), where the aggregation hampers the intramolecular motion between the donor and the acceptor, hence leading to enhanced fluorescent emission as well as a blue shift in the emission peak (15). Spherical nanoaggregates were observed at high water content (≥99 vol %) (Fig.…”

Restriction of Photoinduced Twisted Intramolecular Charge Transfer

“…To date, however, discoveries of organic AIEE systems are still quite limited, especially considering the enormously increasing number of luminescent compounds. Furthermore, intensive investigations of the AIEE mechanism, especially the structure-property relationship [20,21] and the related molecular photophysics, [22][23][24][25] which…”

Control of Emission Color of High Quantum Yield CH3NH3PbBr3 Perovskite Quantum Dots by Precipitation Temperature

“…The reprecipitation technique employed here has been used for organic nanoparticles, polymer dots and organolead halide perovskites via the similar solvent mixing scheme 32, 33, 34, 35, 36, 37, 38, 39. In the present system, good solvent ( N ‐dimethylformamide, DMF) containing precursors and long‐chain ligands (typically with 18 carbon atom chains, which is longer than previously reported by the Pérez‐Prieto and co‐workers22 and Zhang et al 26.…”