ORCID Profile
0000-0001-6012-8856
Current Organisation
Hong Kong University of Science and Technology
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Publisher: Wiley
Date: 09-05-2021
Abstract: Development of simple and efficient red emissive luminogens is desirable yet challenging for optoelectronic devices due to the limited molecular design and the difficulties of synthesis. Red emitting molecules possess large π‐conjugated systems, which permit quenching in the solid state due to π–π stacking and are detrimental to the performance of devices. Furthermore, traditional red emitters usually exhibit emission far from pure red in the standard red, green, and blue (sRGB) gamut. Herein, two red luminogens, DCMa and DCIs, with aggregation‐induced emission (AIE) characteristics based on simple donor–acceptor (D–A) structures are explored. They show high fluorescence quantum yields (QYs) of 13.2% and 7.8% in the film state. Efficient nondoped solution‐processed organic light emitting diodes (OLEDs) with a configuration of indium tin oxide (ITO) oly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) oly[(9,9‐dioctylfluorenyl‐2,7‐diyl)‐ co ‐(4,40‐( N ‐(4‐sec‐butylphenyl)diphenylamine)] (TFB)/DCMa or DCIs/(1,3,5‐tris(2‐ N ‐phenylbenzimidazolyl)benzene) (TPBi)/LiF/Al are fabricated, which emit red electroluminescence at 652 and 711 nm, respectively. Furthermore, they exhibit International Commission on Illumination (CIE) coordinates of (0.63, 0.36) and (0.64, 0.35), respectively, which are close to the value of the primary red color (0.63, 0.34) according to the digital television standard. These results of small molecules DCMa and DCIs suggest future methods for designing new red emitters for nondoped solution‐processed OLEDs.
Publisher: American Chemical Society (ACS)
Date: 03-08-2018
Abstract: Far-red and near-infrared (NIR) fluorescent materials possessing the characteristics of strong two-photon absorption and aggregation-induced emission (AIE) as well as specific targeting capability are much-sought-after for bioimaging and therapeutic applications due to their deep penetration depth and high resolution. Herein, a series of dipolar far-red and NIR AIE luminogens with a strong push-pull effect are designed and synthesized. The obtained fluorophores display bright far-red and NIR solid-state fluorescence with a high quantum yield of up to 30%, large Stokes shifts of up to 244 nm, and large two-photon absorption cross-sections of up to 887 GM. A total of three neutral AIEgens show specific lipid droplet (LD)-targeting capability, while the one with cationic and lipophilic characteristics tends to target the mitochondria specifically. All of the molecules demonstrate good biocompatibility, high brightness, and superior photostability. They also serve as efficient two-photon fluorescence-imaging agents for the clear visualization of LDs or mitochondria in living cells and tissues with deep tissue penetration (up to 150 μm) and high contrast. These AIEgens can efficiently generate singlet oxygen upon light irradiation for the photodynamic ablation of cancer cells. All of these intriguing results prove that these far-red and NIR AIEgens are excellent candidates for the two-photon fluorescence imaging of LDs or mitochondria and organelle-targeting photodynamic cancer therapy.
Publisher: Wiley
Date: 21-05-2022
Abstract: Liquid‐liquid phase separation (LLPS) drives membraneless organelles (MLOs) formation for organizing biomolecules. Artificial MLOs (AMLOs) have been constructed mostly via the LLPS of engineered proteins capable of regulating limited types of biomolecules. Here, leveraging a minimalist AMLO, driven by LLPS of polymer‐oligopeptide hybrids, enrichment, recruitment, and release of multifaceted cargoes are quantitatively shown, including small fluorescent molecules, fluorophore‐containing macromolecules, proteins, DNAs, and RNAs. Cargoes show up to 10 5 ‐fold enrichment, whilst recruitment and release are triggered by variations of temperature, pH, and/or ionic strength. Also, the first efficacious, rapid, and reversible control of aggregation‐induced emission with over 30 folds of modulation of overall fluorescence intensity is achieved, by intensifying the aggregation of luminogens in AMLO. The AMLO is a simple yet versatile platform for potential drug delivery and biosensor applications.
Publisher: American Chemical Society (ACS)
Date: 15-05-2023
Publisher: Wiley
Date: 28-09-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2MH00537A
Abstract: Leveraging complex coacervation of a polycation and a bivalent anion with aggregation-induced emission characteristics, we accomplish eight basic logic operations, producing Boolean-like ‘outputs’ with contrast higher than one order of magnitude.
Publisher: Wiley
Date: 10-01-2022
Abstract: Phototheranostic agents have thrived as promising tools for cancer theranostics because of the integration of sensitive in situ fluorescence imaging and effective multi‐model synergistic therapy. However, how to manipulate the intangible photon energy transfer to balance the competitive radiative and nonradiative processes is still challenging. Although numerous phototheranostic molecules are reported, their complicated molecular design and tedious synthesis often stumble further their development. Herein, three simple molecules with electron donating−accepting structures are developed. The electron acceptor engineering on molecules by introducing acridinium unit gives rise to TPEDCAc with aggregation‐induced second near‐infrared emission (AIE NIR‐II), high reactive oxygen species generation capability, and excellent photothermal conversion efficiency (44.8%) due to the drastic intramolecular motion of large acridinium rotor and balanced AIE effect. Experimental analysis and calculation on the controlled molecules suggested that large torsional angle and the strong electron‐withdrawing ability of the acridinium unit are keys for NIR‐II emission and balanced photodynamic hotothermal conversion. Impressively, the positively charged TPEDCAc shows mitochondria‐targeting capability and high performance in in vivo multi‐modal cancer theranostics under NIR laser irradiation. Hence, this work not only provides a single NIR‐II AIE‐based multi‐modal cancer theranostic system but inspires new insights into future development of new theranostic platforms.
Publisher: American Chemical Society (ACS)
Date: 24-07-2023
Publisher: American Chemical Society (ACS)
Date: 28-03-2019
DOI: 10.1021/JACS.9B00636
Abstract: Although photodynamic therapy (PDT) has thrived as a promising treatment, highly active photosensitizers (PSs) and intense light power can cause treatment overdose. However, extra therapeutic response probes make the monitoring process complicated, ex situ and delayed. Now, this challenge is addressed by a self-reporting cationic PS, named TPE-4EP+, with aggregation-induced emission characteristic. The molecule undergoes mitochondria-to-nucleus translocation during apoptosis induced by PDT, thus enabling the in situ real-time monitoring via fluorescence migration. Moreover, by molecular charge engineering, we prove that the in situ translocation of TPE-4EP+ is mainly attributed to the enhanced interaction with DNA imposed by its multivalent positive charge. The ability of PS to provide PDT with real-time diagnosis help control the treatment dose that can avoid excessive phototoxicity and minimize potential side effect. Future development of new generation of PS is envisioned.
No related grants have been discovered for Tianfu Zhang.