Hao Sun

Bio: Hao Sun is an academic researcher from China University of Mining and Technology. The author has contributed to research in topics: Methyl group & BODIPY. The author has an hindex of 1, co-authored 1 publications receiving 15 citations.

Tuning the fluorescence based on the combination of TICT and AIE emission of a tetraphenylethylene with D–π–A structure

Abstract: A simple D–π–A structured tetraphenylethylene with two electron-rich methyloxy groups and two electron withdrawing cyano groups, which features both twisted intramolecular charge-transfer (TICT) and aggregation-induced emission (AIE) properties, namely TPEOMeCN has been prepared. The emission of TPEOMeCN examined in various solvents is dependent on the polarities of solvents, which indicates the TICT character. The emission intensity of the compound also enhances with the increasing water fraction in H2O–DMSO mixtures, demonstrating the typical AIE property. Excitingly, the TICT and AIE emission could be observed separately or simultaneously by adjusting the water fraction or viscosity of the solvent. Encouragingly, the combined emission of the TPEOMeCN derived from this single molecule could be readily tuned via regulating the viscosity of the system, resulting in a broad emission peak which covers the visible spectrum (400–700 nm). This work provides a general strategy for designing molecules combining TICT emission and AIE for application as full-color emitters.

Donor–Acceptor Type Pendant Conjugated Molecules Based on a Triazine Center with Depressed Intramolecular Charge Transfer Characteristics as Gain Media for Organic Semiconductor Lasers

Abstract: A set of fluorene-capped pendant conjugated molecules (T-m and T-p), which consist of a triazine center with three carbazole substituents as the donor-acceptor (D-A) type pendant structure, were designed, synthesized, and investigated as gain media for organic semiconductor lasers (OSLs). In particular, varying the capping positions of the fluorene units on the pendant core structures results in significantly different intramolecular charge transfer (ICT) properties, where T-m manifested depressed ICT characteristic and high fluorescence quantum yield. The lowest amplified spontaneous emission (ASE) threshold in neat films was recorded as 1.9 μJ cm-2 for T-m and 83.8 μJ cm-2 for T-p, which indicated that the depressed ICT characteristics in the case of T-m help to enhance the ASE properties. Remarkably, the ASE threshold remained almost unchanged and the ASE spectra showed very small shifts (within 1 nm) for T-m with film samples annealed up to 180 °C in open air. In contrast, its linear counterpart 2FEtCz-m showed a clearly increased ASE threshold upon annealing above 100 °C. The results suggest that the selective construction of conjugated pendant molecules with depressed ICT characteristics is beneficial for finely modulating the optical and electrical properties as well as improving the thermostability and photostability, which manifests the great potential as a robust gain media for OSLs.