ORCID Profile
0000-0001-6557-453X
Current Organisation
City University of Hong Kong
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Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1TC04184C
Abstract: Aryl carbonyl-based triplet harvesting luminescent materials are reviewed, with special focus on their molecular design strategies and the relationship among their structures, physical properties and performances.
Publisher: IOP Publishing
Date: 19-06-2017
Abstract: Polymer dots (Pdots) have emerged as a new type of fluorescent probe material for biomedical applications and have attracted great interest due to their excellent optical properties and biocompatability. In this work, we report on a red-emitting P
Publisher: Springer Science and Business Media LLC
Date: 03-05-2023
DOI: 10.1038/S41467-023-38237-7
Abstract: Epitaxial growth is one of the most commonly used strategies to precisely tailor heterostructures with well-defined compositions, morphologies, crystal phases, and interfaces for various applications. However, as epitaxial growth requires a small interfacial lattice mismatch between the components, it remains a challenge for the epitaxial synthesis of heterostructures constructed by materials with large lattice mismatch and/or different chemical bonding, especially the noble metal-semiconductor heterostructures. Here, we develop a noble metal-seeded epitaxial growth strategy to prepare highly symmetrical noble metal-semiconductor branched heterostructures with desired spatial configurations, i.e., twenty CdS (or CdSe) nanorods epitaxially grown on twenty exposed (111) facets of Ag icosahedral nanocrystal, albeit a large lattice mismatch (more than 40%). Importantly, a high quantum yield (QY) of plasmon-induced hot-electron transferred from Ag to CdS was observed in epitaxial Ag-CdS icosapods (18.1%). This work demonstrates that epitaxial growth can be achieved in heterostructures composed of materials with large lattice mismatches. The constructed epitaxial noble metal-semiconductor interfaces could be an ideal platform for investigating the role of interfaces in various physicochemical processes.
Publisher: Wiley
Date: 18-07-2018
Abstract: Exploring of new catalyst activation principle holds a key to unlock catalytic powers of cheap and earth-abundant materials for large-scale applications. In this regard, the vacancy defects have been proven to be effective to initiate catalytic active sites and endow high electrocatalytic activities. However, such electrocatalytically active defects reported to date have been mostly formed by anion vacancies. Herein, it is demonstrated for the first time that iron cation vacancies induce superb water splitting bifunctionality in alkaline media. A simple wet-chemistry method is developed to grow ultrathin feroxyhyte (δ-FeOOH) nanosheets with rich Fe vacancies on Ni foam substrate. The theoretical and experimental results confirm that, in contrast to anion vacancies, the formation of rich second neighboring Fe to Fe vacancies in δ-FeOOH nanosheets can create catalytic active centers for both hydrogen and oxygen evolution reactions. The atomic level insight into the new catalyst activation principle based on metal vacancies is adaptable for developing other transition metal electrocatalysts, including Fe-based ones.
Publisher: Wiley
Date: 23-08-2018
Abstract: Multifunctional emitting materials are scarce and need to be further explored. Now, a newly anthraquinone derivative, 2-(phenothiazine-10-yl)-anthraquinone (PTZ-AQ) was designed and synthesized and found to demonstrate polymorphism, multi-color emission, aggregation-induced emission (AIE), mechanochromic luminescence (MCL), and thermally activated delayed fluorescence (TADF) in its different solid forms. It is shown for the first time that TADF properties of a compound can be systematically tuned via its aggregation state. The optimized PTZ-AQ crystal shows a small singlet-triplet energy splitting of 0.01 eV and exhibits red TADF with a photoluminescence quantum yield as high as 0.848. This study shows that the unique multiple functions can be integrated into one single compound through controlling the aggregation states, which provides a new strategy for the investigation and application of multifunctional organic materials.
Publisher: Wiley
Date: 25-08-2016
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.BIOMATERIALS.2018.07.042
Abstract: Understanding the relationship between polymer chemical structure and its performance of photoacoustic imaging (PAI) and photothermal therapy (PTT) is important for developing ideal PAI/PTT agents. In this report, four semiconducting polymer nanoparticles (SPNs) with different donor-acceptor architectures are self-assembled for highly effective PAI-guided PTT. In particular, SPN1 with the longest π-conjugation length and the highest mass extinction coefficient which are beneficial for intramolecular charge transfer as well as light harvesting, exhibits the highest photothermal conversion efficiency up to 52.6%. Moreover, the as-prepared SPN1 possess good water-dispersibility, robust size-stability and excellent photothermal properties. Furthermore, the SPN1 not only exhibits a remarkable cancer cell-killing ability but also shows a prominent tumor inhibition capacity. Finally, the as-prepared water-dispersible SPN1 displays good biocompatibility and biosafety, making it a promising candidate for future biomedical applications. Considering the plenty of near-infrared absorbing semiconducting polymer available, our work provides fundamental insights for rational design and preparation of highly efficient SPN-based PAI/PTT agents for cancer theranostics.
Publisher: American Chemical Society (ACS)
Date: 10-02-2017
Abstract: Ruthenium(II) tris(bipyridyl) cationic complex (Ru(bpy)
Publisher: AIP Publishing
Date: 05-2015
DOI: 10.1063/1.4921993
Abstract: A comprehensive study on inverted organic solar cells (OSCs) with a moth’s eye nanostructured (MEN) active layer was carried out. Performance of the MEN-based OSCs and the corresponding control planar cells, fabricated with blend of poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bA] dithiophene-2, 6-diyl][3-fluoro-2-[(2- ethylhexyl) carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7):[6,6]- phenyl-C70- butyric-acid-methyl-ester (PC70BM) was analyzed. The efficiency of the MEN-based OSCs was optimized by adjusting the height of MEN pattern in the active layer. Our experimental and theoretical results reveal that the MEN pattern enhances light absorption in the PTB7:PC70BM active layer, especially over the long wavelength region. This leads to a 7.8% increase in short circuit current density and a 6.1% increase in power conversion efficiency over those of the control planar cell.
Publisher: American Chemical Society (ACS)
Date: 08-07-2015
Abstract: Enhancing light outcoupling in flexible organic light-emitting diodes (FOLEDs) is an important task for increasing their efficiencies for display and lighting applications. Here, a strategy for an angularly and spectrally independent boost in light outcoupling of FOLEDs is demonstrated by using plastic substrates with a low refractive index, consisting of a bioinspired optical coupling layer and a transparent conductive electrode composed of a silver network. The good transmittance to full-color emission (>94% over the whole visible wavelength range), ultralow sheet resistance to carrier injection (<5 Ω sq(-1)), and high tolerance to mechanical bending of the ameliorated plastic substrates synergistically optimize the device performance of FOLEDs. The maximum power efficiencies reach 47, 93, 56, and 52 lm W(-1) for red, green, blue, and white emissions, which are competitive with similarly structured OLEDs fabricated on traditional indium-tin-oxide (ITO) glass. This paradigm for light outcoupling enhancement in ITO-free FOLEDs offers additional features and design freedoms for highly efficient flexible optoelectronics in large-scale and low-cost manufacturing without the need for a high-refractive-index plastic substrate.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0CC08323B
Abstract: Applying the heavy-atom effect to TADF photosensitizers achieves ultra-high 1 O 2 generation ( Ф Δ = 0.91) by the synergetic effect of small Δ E ST and considerable SOC.
Publisher: American Chemical Society (ACS)
Date: 27-04-2020
Publisher: Wiley
Date: 12-07-2017
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.BIOMATERIALS.2022.121730
Abstract: Transforming growth factor β (TGF-β) is a well-known key mediator for the progression and metastasis of lung carcinoma. However, cost-effective anti-TGF-β therapeutics for lung cancer remain to be explored. Specifically, the low efficacy in drug delivery greatly limits the clinical application of small molecular inhibitors of TGF-β. In the present study, specific inhibitor of Smad3 (SIS3) is developed into a self-carried nanodrug (SCND-SIS3) using the reprecipitation method, which largely improves its solubility and bioavailability while reduces its nephrotoxicity. Compared to unmodified-SIS3, SCND-SIS3 demonstrates better anti-cancer effects through inducing tumor cell apoptosis, inhibiting angiogenesis, and boosting NK cell-mediated immune responses in syngeneic Lewis Lung Cancer (LLC) mouse model. Better still, it could achieve comparable anti-cancer effect with just one-fifth the dose of unmodified-SIS3. Mechanistically, RNA-sequencing analysis and cytokine array results unveil a TGF-β/Smad3-dependent immunoregulatory landscape in NK cells. In particular, SCND-SIS3 promotes NK cell cytotoxicity by ameliorating Smad3-mediated transcriptional inhibition of Ndrg1. Furthermore, improved NK cell cytotoxicity by SCND-SIS3 is associated with higher expression of activation receptor Nkp46, and suppressed levels of Trib3 and TSP1 as compared with unmodified-SIS3. Taken together, SCND-SIS3 possesses superior anti-cancer effects with enhanced bioavailability and biocompatibility, therefore representing as a novel therapeutic strategy for lung carcinoma with promising clinical potential.
Publisher: Wiley
Date: 09-01-2023
Abstract: The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo‐controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric‐demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo‐planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo‐controllable luminescent radical system is employed for a high‐level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart‐responsive materials for advanced applications.
Publisher: American Chemical Society (ACS)
Date: 22-10-2018
DOI: 10.1021/ACS.NANOLETT.8B03043
Abstract: To make nanomedicine potentially applicable in a clinical setting, several methods have been developed to synthesize pure nanodrugs (PNDs) without using any additional inert carriers. In this work, we report a novel green, low-cost, and scalable ice-template-assisted approach which shows several unique characteristics. First, the whole process only requires adding a drug solution into an ice template and subsequent melting (or freeze-drying), allowing easy industrial mass production with low capital investment. Second, the production yield is much higher than that of the traditional reprecipitation approach. The yield of Curcumin (Cur) PNDs is over two orders (∼140 times) magnitude higher than that obtained in a typical reprecipitation preparation. By adjusting simple processing parameters, PNDs with different sizes (∼20-200 nm) can be controllably obtained. Finally, the present approach can be easily applicable for a wide range of hydrophobic therapeutic drugs without any structural modification.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TC00086B
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NJ01921A
Abstract: A new pyrene cored small organic molecule exhibiting a high PLQY and blue emission was designed and synthesized.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC05130H
Abstract: We applied organic nanostructures based on TADF emitters for singlet oxygen generation.
Publisher: Wiley
Date: 28-12-2015
Publisher: Wiley
Date: 16-04-2021
Abstract: Extensive recent efforts have been put on the design of high‐performance organic near‐infrared (NIR) photothermal agents (PTAs), especially over NIR‐II bio‐window (1000–1350 nm). So far, the development is mainly limited by the rarity of molecules with good NIR‐II response. Here, we report organic nanoparticles of intermolecular charge‐transfer complexes (CTCs) with easily programmable optical absorption. By employing different common donor and acceptor molecules to form CTC nanoparticles (CT NPs), absorption peaks of CT NPs can be controllably tuned from the NIR‐I to NIR‐II region. Notably, CT NPs formed with perylene and TCNQ have a considerably red‐shifted absorption peak at 1040 nm and achieves a good photothermal conversion efficiency of 42 % under 1064 nm excitation. These nanoparticles were used for antibacterial application with effective activity towards both Gram‐negative and Gram‐positive bacteria. This work opens a new avenue into the development of efficient PTAs.
Publisher: Wiley
Date: 23-08-2018
Publisher: Wiley
Date: 15-02-2017
Publisher: Springer Science and Business Media LLC
Date: 13-09-2023
Publisher: Springer Science and Business Media LLC
Date: 19-04-2016
DOI: 10.1038/SREP24476
Abstract: Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm 2 V −1 s −1 ), on/off ratio (10 7 ), and other desirable field-effect properties that meet impactful OFET application requirements.
Publisher: American Chemical Society (ACS)
Date: 11-12-2018
Abstract: Many highly ordered structures with smart functions are generated by self-assembly with stimuli responsiveness. Despite that electron microscopes enable us to directly observe the end products, it is hard to visualize the initial step and the kinetic stimuli-responsive behavior of self-assembly. Here, we report the design and synthesis of stereogenic hiphiles, namely, ( Z)-TPE-OEG and ( E)-TPE-OEG, with aggregation-induced emission (AIE) characteristics from the hydrophobic tetraphenylethene core and thermoresponsive behavior from the hydrophilic oligoethylene glycol monomethyl ether chain. The two isomers can be easily isolated by high-performance liquid chromatography and characterized by 2D NMR spectroscopy. While ( Z)-TPE-OEG self-assembles into vesicles, its ( E)-cousin forms micelles in water. The initial step of their self-assembly processes can be visualized based on AIE characteristics, with a sensitivity much higher than the method based on transmittance measurement. The entrapment and release capabilities of the ( Z)-stereogenic hiphile are demonstrated by employing pyrene as a guest. The thermoresponsive behavior of the ( Z)- hiphile results in its continuous phase transition from microscopic self-assembly to macroscopic aggregation, which is successfully visualized in situ by confocal laser scanning microscopy accompanied by the AIE technique. Such a kinetic process shows different stages according to the microscopic visualization, and these stages have never been monitored through roughly observing the appearance of precipitates. It is anticipated that this study can deepen the understanding of the self-assembly processes for better monitoring and controlling them in different systems.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TC03690A
Abstract: Two new solution processable pyrene based electroluminescent organic semiconductors ( PY-PH & PY-CA ) and their OLED performance reported.
Publisher: Springer Science and Business Media LLC
Date: 02-12-2021
DOI: 10.1038/S41377-021-00676-6
Abstract: The benchmark tin oxide (SnO 2 ) electron transporting layers (ETLs) have enabled remarkable progress in planar perovskite solar cell (PSCs). However, the energy loss is still a challenge due to the lack of “hidden interface” control. We report a novel ligand-tailored ultrafine SnO 2 quantum dots (QDs) via a facile rapid room temperature synthesis. Importantly, the ligand-tailored SnO 2 QDs ETL with multi-functional terminal groups in situ refines the buried interfaces with both the perovskite and transparent electrode via enhanced interface binding and perovskite passivation. These novel ETLs induce synergistic effects of physical and chemical interfacial modulation and preferred perovskite crystallization-directing, delivering reduced interface defects, suppressed non-radiative recombination and elongated charge carrier lifetime. Power conversion efficiency (PCE) of 23.02% (0.04 cm 2 ) and 21.6% (0.98 cm 2 , V OC loss: 0.336 V) have been achieved for the blade-coated PSCs (1.54 eV E g ) with our new ETLs, representing a record for SnO 2 based blade-coated PSCs. Moreover, a substantially enhanced PCE ( V OC ) from 20.4% (1.15 V) to 22.8% (1.24 V, 90 mV higher V OC , 0.04 cm 2 device) in the blade-coated 1.61 eV PSCs system, via replacing the benchmark commercial colloidal SnO 2 with our new ETLs.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Wiley
Date: 16-04-2021
Abstract: Extensive recent efforts have been put on the design of high‐performance organic near‐infrared (NIR) photothermal agents (PTAs), especially over NIR‐II bio‐window (1000–1350 nm). So far, the development is mainly limited by the rarity of molecules with good NIR‐II response. Here, we report organic nanoparticles of intermolecular charge‐transfer complexes (CTCs) with easily programmable optical absorption. By employing different common donor and acceptor molecules to form CTC nanoparticles (CT NPs), absorption peaks of CT NPs can be controllably tuned from the NIR‐I to NIR‐II region. Notably, CT NPs formed with perylene and TCNQ have a considerably red‐shifted absorption peak at 1040 nm and achieves a good photothermal conversion efficiency of 42 % under 1064 nm excitation. These nanoparticles were used for antibacterial application with effective activity towards both Gram‐negative and Gram‐positive bacteria. This work opens a new avenue into the development of efficient PTAs.
Publisher: Wiley
Date: 15-03-2016
Publisher: American Chemical Society (ACS)
Date: 21-12-2021
DOI: 10.1021/JACS.1C11313
Publisher: Springer Science and Business Media LLC
Date: 24-12-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC01956H
Abstract: A series of strong electron-rich small molecules based on acenes were designed and synthesized for application in green/blue organic light-emitting diodes and perovskite solar cells.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TB01154D
Abstract: Novel photoactive metal–organic framework nanoparticles were developed using a facile post-synthetic conjugation method to achieve tunable combinational PDT and PTT.
Publisher: Royal Society of Chemistry (RSC)
Date: 26-09-2014
DOI: 10.1039/C4CP03693J
Abstract: In this work, three novel pyrene cored small conjugated molecules, namely 1,3,6,8-tetrakis(6-(octyloxy)naphthalene-2-yl)pyrene (PY-1), 1,3,6,8-tetrakis((E)-2-(6-(n-octyloxy)naphthalene-2-yl)vinyl)pyrene (PY-2) and 1,3,6,8-tetrakis((6-(n-octyloxy)naphthalene-2-yl)ethynyl)pyrene (PY-3) have been synthesized by Suzuki, heck and Sonogashira organometallic coupling reactions, respectively. The effects of single, double and triple bonds on their optical, electrochemical, and thermal properties are studied in detail. These are all materials fluorescent and they have been used in organic light-emitting diodes (OLEDs) and their electroluminescent properties have been studied.
Publisher: American Chemical Society (ACS)
Date: 29-04-2016
Abstract: In this study, we report fluorescent organic nanoprobes with intense blue, green, and orange-red emissions prepared by self-assembling three carbazole derivatives into nanorods/nanoparticles. The three compounds consist of two or four electron-donating carbazole groups linked to a central dicyanobenzene electron acceptor. Steric hindrance from the carbazole groups leads to noncoplanar 3D molecular structures favorable to fluorescence in the solid state, while the donor-acceptor structures endow the molecules with good two-photon excited emission properties. The fluorescent organic nanoprobes exhibit good water dispersibility, low cytotoxicity, superior resistance against photodegradation and photobleaching. Both one- and two-photon fluorescent imaging were shown in the A549 cell line. Two-photon fluorescence imaging with the fluorescent probes was demonstrated to be more effective in visualizing and distinguishing cellular details compared to conventional one-photon fluorescence imaging.
Publisher: Elsevier BV
Date: 06-2015
Publisher: Ivyspring International Publisher
Date: 2017
DOI: 10.7150/THNO.18460
Publisher: Wiley
Date: 09-01-2023
Abstract: The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo‐controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric‐demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo‐planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo‐controllable luminescent radical system is employed for a high‐level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart‐responsive materials for advanced applications.
Publisher: American Chemical Society (ACS)
Date: 19-11-2015
Abstract: Fluorescent organic nanoparticles based on small molecules have been regarded as promising candidates for bioimaging in recent years. In this study, we report a highly stable near-infrared (NIR) fluorescent organic nanoprobes based on nanoparticles of an anthraquinone derivate with strong aggregation-induced emission (AIE) characteristics and a large Stokes shift (>175 nm). These endow the nanoprobe with high fluorescent brightness and high signal-to-noise ratio. On the other hand, the nanoprobe also shows low cytotoxicity, good stability over a wide pH range, superior resistance against photodegradation and photobleaching comparing to typical commercial fluorescent organic dyes such as fluorescein sodium. Endowed with such merits in term of optical performance, biocompatibility, and stability, the nanoprobe is demonstrated to be an ideal fluorescent probe for noninvasive long-term cellular tracing and imaging applications. As an ex le, it is shown that strong red fluorescence from the nanoprobe can still be clearly observed in A549 human lung cancer cells after incubation for six generations over 15 days.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR04436G
Abstract: The core–shell nanoparticles are constructed by encapsulating the g-C 3 N 4 nanosheet into ZIF-8 shells for dual-color fluorescence imaging and combined photo-chemo therapy.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TA09138A
Abstract: FeS nanoparticles embedded in porous carbon matrix with unique structure was successfully synthesized and shows impressive lithium ion battery performances.
Publisher: American Chemical Society (ACS)
Date: 13-01-2015
DOI: 10.1021/AM5072833
Abstract: Tunable charge-trapping behaviors including unipolar charge trapping of one type of charge carrier and ambipolar trapping of both electrons and holes in a complementary manner is highly desirable for low power consumption multibit flash memory design. Here, we adopt a strategy of tuning the Fermi level of reduced graphene oxide (rGO) through self-assembled monolayer (SAM) functionalization and form p-type and n-type doped rGO with a wide range of manipulation on work function. The functionalized rGO can act as charge-trapping layer in ambipolar flash memories, and a dramatic transition of charging behavior from unipolar trapping of electrons to ambipolar trapping and eventually to unipolar trapping of holes was achieved. Adjustable hole/electron injection barriers induce controllable Vth shift in the memory transistor after programming operation. Finally, we transfer the ambipolar memory on flexible substrates and study their charge-trapping properties at various bending cycles. The SAM-functionalized rGO can be a promising candidate for next-generation nonvolatile memories.
No related grants have been discovered for Chun-Sing LEE.