ORCID Profile
0000-0001-6534-4953
Current Organisations
The Chinese University of Hong Kong, Shenzhen
,
Hong Kong University of Science and Technology
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Publisher: American Chemical Society (ACS)
Date: 20-01-2022
DOI: 10.1021/JACS.1C11480
Abstract: Long-persistent luminescence (LPL), also known as afterglow, is a phenomenon in which the material shows long-lasting luminescence after the cessation of the excitation source. The research of LPL continues to attract much interest due to its fundamental nature and its potential in the development of the next generation of functional materials. However, most of the current LPL materials are multicomponent inorganic systems obtained after harsh synthetic procedures and often use rare-earth metals. Recently, metal free organic long-persistent luminescence (OLPL) has gained much interest because it can bypass many of the disadvantages of inorganic systems. To date, the most successful method to generate OLPL systems is to access charge-separated states through binary donor-acceptor exciplex systems. However, it has been reported that the ratios of the binary systems affect OLPL properties, complicating the reproducibility and large-scale production of OLPL materials. Simpler OLPL systems can overcome these issues for the benefit of the development and adoption of OLPL systems. Here, we report on the rational design and synthesis of a single-component OLPL system with detectable afterglow for at least 12 min under ambient conditions. This work exemplifies an easy design principle for new OLPL materials. The investigation of the material provides valuable insights toward the generation of OLPL from a single-component system.
Publisher: Wiley
Date: 28-02-2019
Publisher: American Chemical Society (ACS)
Date: 19-01-2021
Publisher: American Chemical Society (ACS)
Date: 28-01-2021
DOI: 10.1021/JACS.0C13178
Publisher: Wiley
Date: 28-02-2019
Abstract: The development of molecular machines requires new building blocks which are easy to characterize and visualize to realize a complexity comparable to their natural counterparts such as biological enzymes. Furthermore, with the desire to build functional nanobots capable of navigating living organisms, it is necessary that the building blocks show mobility even in the solid state. Herein we report a system which is emissive in the amorphous state but is non-fluorescent in the crystalline state due to the formation of extensive π-π interactions. This dual nature could be exploited for easy visualization of its solid-state molecular rearrangement. The emission of the amorphous film was quenched as the molecules spontaneously formed π-π interactions even in the solid state. Scratching the non-emissive film destroyed the interactions and restored the emission of the film. The emission quickly disappeared with an average lifetime of 20 s as the compound reformed the π-network even at room temperature.
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Chemical Society (ACS)
Date: 24-07-2023
Publisher: Wiley
Date: 22-04-2020
Publisher: Springer Science and Business Media LLC
Date: 14-11-2019
DOI: 10.1038/S41467-019-13048-X
Abstract: Purely organic room temperature phosphorescence (RTP) has attracted wide attention recently due to its various application potentials. However, ultralong RTP (URTP) with high efficiency is still rarely achieved. Herein, by dissolving 1,8-naphthalic anhydride in certain organic solid hosts, URTP with a lifetime of over 600 ms and overall quantum yield of over 20% is realized. Meanwhile, the URTP can also be achieved by mechanical excitation when the host is mechanoluminescent. Femtosecond transient absorption studies reveal that intersystem crossing of the host is accelerated substantially in the presence of a trace amount of 1,8-naphthalic anhydride. Accordingly, we propose that a cluster exciton spanning the host and guest forms as a transient state before the guest acts as an energy trap for the RTP state. The cluster exciton model proposed here is expected to help expand the varieties of purely organic URTP materials based on an advanced understanding of guest/host combinations.
Publisher: American Chemical Society (ACS)
Date: 27-09-2017
Publisher: Wiley
Date: 13-01-2023
Abstract: Photoswitches with multiple fluorescence states known as photofluorochromism upon photo‐induced isomerization show practical applications in information storage, anticounterfeiting, and sensors. However, it is still challenging to realize rapid isomerization, efficient fluorescence, and gradient signal output simultaneously. Herein, by incorporating luminogenic units with aggregation‐induced emission (AIE) features into photo‐responsive hydrazone, a series of novel photofluorochromic AIE compounds are developed. These newly designed compounds exhibit quantum yields of up to 38.4% and could undergo reversible and swift photo‐isomerization upon 450/365 nm irradiation. Accordingly, the fabricated photopatterns based on them are utilized as quantitatively described images for information storage, which show excellent rewritability and intensity‐variable fluorescence with a high resolution of 10 µm. This work provides a new strategy to develop intelligent photopattern systems with continuous gradient fluorescence for information storage and cybernetics.
Publisher: Wiley
Date: 04-10-2021
Abstract: Microscopic control of macroscopic phenomena is one of the core subjects in materials science. Particularly, the spatio‐temporal control of material behaviors through a non‐contact way is of fundamental importance but is difficult to accomplish. Herein, a strategy to realize remote spatio‐temporal control of luminescence behaviors is reported. A multi‐arm salicylaldehyde benzoylhydrazone‐based aggregation‐induced emission luminogen (AIEgen)/metal‐ion system, of which the fluorescence can be gated by the UV irradiation with time dependency, is developed. By changing the metal‐ion species, the fluorescence emission and the intensity can also be tuned. The mechanism of the UV‐mediated fluorescence change is investigated, and it is revealed that a phototriggered aggregation‐induced emission (PTAIE) process contributes to the behaviors. The AIEgen is further covalently integrated into a polymeric network and the formed gel/metal‐ion system can achieve laser‐mediated mask‐free writing enabled by the PTAIE process. Moreover, by further taking advantage of the time‐dependent self‐healing property of hydrazone‐based dynamic covalent bond, transformable 4D soft patterns are generated. The findings and the strategy increase the ways to manipulate molecules on the supramolecule or aggregate level. They also show opportunities for the development of controllable smart materials and expand the scope of the materials in advanced optoelectronic applications.
Publisher: Wiley
Date: 25-09-2017
Abstract: The detection of food spoilage is a major concern in food safety as large amounts of food are transported globally. Direct analysis of food s les is often time-consuming and requires expensive analytical instrumentation. A much simpler and more cost-effective method for monitoring food fermentation is to detect biogenic amines generated as a by-product during food decomposition. In this work, a series of 1,2-dihydroquinoxaline derivatives (DQs) with aggregation-induced emission (AIE) characteristics were synthesised and their protonated forms, that is, H
Publisher: Chinese Chemical Society
Date: 05-08-2022
Publisher: Wiley
Date: 17-06-2021
Abstract: The unique advantages and the exciting application prospects of AIEgens have triggered booming developments in this area in recent years. Among them, stimuli‐responsive AIEgens have received particular attention and impressive progress, and they have been demonstrated to show tremendous potential in many fields from physical chemistry to materials science and to biology and medicine. Here, the recent achievements of stimuli‐responsive AIEgens in terms of seven most representative types of stimuli including force, light, polarity, temperature, electricity, ion, and pH, are summarized. Based on typical ex les, it is illustrated how each type of systems realize the desired stimuli‐responsive performance for various applications. The key work principles behind them are ultimately deciphered and figured out to offer new insights and guidelines for the design and engineering of the next‐generation stimuli‐responsive luminescent materials for more broad applications.
Publisher: American Chemical Society (ACS)
Date: 28-07-2020
DOI: 10.1021/JACS.0C06305
No related grants have been discovered for parvej alam.