CD-based Materials Research Articles

Carbon Dot-Based Composite with Color Excitation-Dependent Room-Temperature Phosphorescence for Advanced Optical Encryption and Anticounterfeiting.

The phenomenon of multicolor afterglow emission has attracted considerable attention in information encryption, bioimaging, and sensing. Consequently, there is a growing demand for the development of multicolor afterglow and phosphorescence switching methods utilizing carbon dot (CD) materials. Herein, multicolor room-temperature phosphorescence (RTP) emission in CD-based materials (PM-CD@BA composite) was achieved by developing multiple emission centers and tuning the excitation wavelength. The color of the afterglow observed in this composite covered from the deep-blue to the green region. The experimental results reveal that under heating treatment, the CDs embedded in inorganic boric acid/B2O3 matrix materials and a rigid framework generated in the composite system effectively suppressed the nonradiative transition and promoted the RTP emission. Finally, high-resolution multilevel RTP 2D code data encryption was realized by inkjet printing technology. The developed concepts of information encryption and anticounterfeiting exhibit the significant potential of CD-based afterglow materials applied in advanced optical applications.

Ultra-broadband triple-peak white light-emitting carbonized polymer dots materials based on Förster resonance energy transfer

Carbonized polymer dots (CPDs) with white-light-emitting property have greatly promising application in next generation of lighting and display technologies. However, most of the reported CPD materials exhibit single peak emission and narrow emission band, resulting in difficulty to obtain white-light emission. In this work, the ultra-broadband triple-peak emission (red, green, and blue) CD-based materials with high-efficiency white light-emitting property are realized for the first time by the Förster resonance energy transfer (FRET). Blue and green emissions are derived from the fluorescence and phosphorescence of donor CPDs, while the red light is derived from receptor by FRET. Remarkably, the fabricated CPD materials show bright pure white-light emission with high overall quantum yield (QY) of 36% and the full width at half maximum of 235 nm. Besides, afterglow colors of CPD-based materials can be tuned from green to red by adjusting the ratio of donor and acceptor. Based on the high-efficiency and wide-spectrum pure white light emission characteristics of CPD-based composites, white light emitting diodes were fabricated and they exhibit bright warm white light with CIE and CCT of (0.35, 0.31) and 4041 K.

Efficient TaON/CdZnS nanorods with enhanced interfacial charge transfer for visible-light-driven hydrogen evolution

Constructing an efficient photoelectron transfer route to improve carrier separation efficiency is crucial for photocatalytic H2 evolution. Herein, TaON nanoparticles modified CdZnS nanorods were successfully prepared via a simple hydrothermal method for efficient H2 evolution under visible light irradiation. Experimental results show that the obtained 12 wt% TaON/CdZnS nanocomposites exhibit remarkable photocatalytic activity reaching to 7.43 mmol h−1 g−1, which was 1.5 times higher than that of pristine CdZnS nanorods. The TaON/CdZnS nanorods promote the abilities of charge separation and transfer by establishing n-n type heterojunctions, thereby promoting photocatalytic hydrogen performance. This work not only demonstrates the TaON as a promising co-catalyst in photocatalysis but also provides a model system for further improvement in Cd-based materials for H2 production.

Ultra-stable and long-lived multi-color room temperature phosphorescent carbon dot and silica composites for data encryption and anti-counterfeiting

Carbon dot (CD)-based room temperature phosphorescence (RTP) materials have garnered fundamental attention due to their unique and irreplaceable advantages. However, developing CD-based materials with stable multi-color RTP emission is also desired. Herein, we present a rational design of carbon dots and SiO2 composite (CD@ Silica) fabrication, which demonstrates excellent stability in its RTP, showcases multi-color emission, and experiences thermal enhancement. Multi-color afterglow emission is achieved in CD/fluorescence dyes@ Silica composite systems due to the high efficiency of the Förster resonant energy transfer (FRET) processes between CDs and fluorescence dyes. The covalent interactions between CDs and silica shells protect the triplet state, and the structure significantly promotes the multi-color RTP emission realized in some challenging environments (such as in acid or alkaline aqueous solution). Utilizing the stable phosphorescence emission, we successfully implement the concepts of multi-level information encryption and fingerprint anti-counterfeiting through CD@ Silica composites.

General Synthesis of Carbon Dot-Based Composites with Triple-Mode Luminescence Properties and High Stability.

Carbon dot (CD)-based luminescent materials have attracted great attention in optical anti-counterfeiting due to their excellent photophysical properties in response to ultraviolet-to-visible excitation. Hence, there is an urgent need for the general synthesis of CD-based materials with multimode luminescence properties and high stability; however, their synthesis remains a formidable challenge. Herein, CDs were incorporated into a Yb,Tm-doped YF3 matrix to prepare CDs@YF3:Yb,Tm composites. The YF3 plays a dual role, not only serving as a host for fixing rare earth luminescent centers but also functioning as a rigid matrix to stabilize the triplet state of the CDs. Under the excitation of 365 nm ultraviolet light and 980 nm near-infrared light, CDs@YF3:Yb,Tm exhibited blue fluorescence and green room-temperature phosphorescence of CDs and upconversion luminescence of Tm3+, respectively. Due to the strong protection of the rigid matrix, the stability of CDs@YF3:Yb,Tm is greatly improved. This work provides a general synthesis strategy for achieving multimode luminescence and high stability of CD-based luminescent materials and offers opportunities for their applications in advanced anti-counterfeiting and information encryption.

Cyclodextrins for Lithium Batteries Applications.

Due to their high energy and power density, lithium-ion batteries (LIBs) have gained popularity in response to the demand for effective energy storage solutions. The importance of the electrode architecture in determining battery performance highlights the demand for optimization. By developing useful organic polymers, cyclodextrin architectures have been investigated to improve the performance of Li-based batteries. The macrocyclic oligosaccharides known as cyclodextrins (CDs) have relatively hydrophobic cavities that can enclose other molecules. There are many industries where this "host-guest" relationship has been found useful. The hydrogen bonding and suitable inner cavity diameter of CD have led to its selection as a lithium-ion diffusion channel. CDs have also been used as solid electrolytes for solid-state batteries and as separators and binders to ensure adhesion between electrode components. This review gives a general overview of CD-based materials and how they are used in battery components, highlighting their advantages.

Optimization of solution-processed amorphous cadmium gallium oxide for high-performance thin-film transistors

Cd-based materials, despite high electron mobility and wide bandgap, are understudied for thin-film transistors. Our study explores solution-processed cadmium gallium oxide as a high-performance thin-film transistors.

Recent Advancements in Cyclodextrin-Based Adsorbents for the Removal of Hazardous Pollutants from Waters.

Water is an essential substance for the survival on Earth of all living organisms. However, population growth has disturbed the natural phenomenon of living, due to industrial growth to meet ever expanding demands, and, hence, an exponential increase in environmental pollution has been reported in the last few decades. Moreover, water pollution has drawn major attention for its adverse effects on human health and the ecosystem. Various techniques have been used to treat wastewater, including biofiltration, activated sludge, membrane filtration, active oxidation process and adsorption. Among the mentioned, the last method is becoming very popular. Moreover, among the sorbents, those based on cyclodextrin have gained worldwide attention due to their excellent properties. This review article overviewed recent contributions related to the synthesis of Cyclodextrin (CD)-based adsorbents to treat wastewater, and their applications, especially for the removal of heavy metals, dyes, and organic pollutants (pharmaceuticals and endocrine disruptor chemicals). Furthermore, new adsorption trends and trials related to CD-based materials are also discussed regarding their regenerative potential. Finally, this review could be an inspiration for new research and could also anticipate future directions and challenges associated with CD-based adsorbents.

Synthesis of Doped/Hybrid Carbon Dots and Their Biomedical Application.

Carbon dots (CDs) are a novel type of carbon-based nanomaterial that has gained considerable attention for their unique optical properties, including tunable fluorescence, stability against photobleaching and photoblinking, and strong fluorescence, which is attributed to a large number of organic functional groups (amino groups, hydroxyl, ketonic, ester, and carboxyl groups, etc.). In addition, they also demonstrate high stability and electron mobility. This article reviews the topic of doped CDs with organic and inorganic atoms and molecules. Such doping leads to their functionalization to obtain desired physical and chemical properties for biomedical applications. We have mainly highlighted modification techniques, including doping, polymer capping, surface functionalization, nanocomposite and core-shell structures, which are aimed at their applications to the biomedical field, such as bioimaging, bio-sensor applications, neuron tissue engineering, drug delivery and cancer therapy. Finally, we discuss the key challenges to be addressed, the future directions of research, and the possibilities of a complete hybrid format of CD-based materials.

Advances and Classification of Cyclodextrin-Based Polymers for Food-Related Issues.

Cyclodextrins (CDs) are a good alternative to reduce or enhance different biomolecule characteristics and have demonstrated great results in food science. However, CDs present intrinsic limitations that can be solved by derivative synthesis. This review represents a survey of the state of the art of CD-based materials and their uses in food science. A deep review of the structure is carried out and different groups for ordination are suggested. After that, different applications such as cholesterol complexation or its use as sensors are reviewed. The derivatives show novel and promising activities for the industry. A critical perspective of the materials suggests that they might not present toxicity, although more studies are required. These points suggest that the research in this field will be increased in the following years.

Terminal Structure of Triethylene Glycol-Tethered Chains on β-Cyclodextrin-Threaded Polyrotaxanes Dominates Temperature Responsivity and Biointeractions.

Pharmacological and biomedical applications of cyclodextrin (CD)-threaded polyrotaxanes (PRXs) have gained increasing attention. We had previously investigated the therapeutic effects of oligo(ethylene glycol) (OEG)-modified β-CD PRXs in congenital metabolic disorders. Although the chemical modification of PRXs is crucial for these applications, the influences of the chemical structure of OEG modified on PRXs were not completely understood. The current study focuses on the terminal group structures of triethylene glycol (TEG)-tethered chains, wherein three series of TEG-tethered PRXs (TEG-PRXs) with various TEG terminal group structures (hydroxy, methoxy, and ethoxy) were synthesized to investigate their physicochemical properties and biointeractions. The methoxy and ethoxy-terminated TEG-PRXs exhibited temperature-dependent phase transitions in phosphate buffer saline and formed coacervate droplets above their cloud points. A comprehensive analysis revealed that the hydrophobicity of the terminal group structures of the TEG-tethered chains played a dominant role in exhibiting temperature-dependent phase transition. Furthermore, the hydrophobicity of the terminal group structures of TEG-tethered chains on PRXs also affected the interactions with lipids and proteins, with the hydrophobic ethoxy-terminated TEG-tethered chains showing the highest interactions. However, in normal human skin fibroblasts, the moderately hydrophobic methoxy-terminated TEG-modified PRXs showed the highest intracellular uptake levels. As a result, we concluded that methoxy-terminated TEG is a suitable chemical modification for the biomedical applications of PRXs due to the negligible temperature responsivity around physiological temperature and significant intracellular uptake levels. The findings of this study shall contribute significantly to the rational design of PRXs and CD-based materials for future pharmacological and biomedical applications.

Application of carbon dots in analysis and detection of antibiotics

抗生素的过度使用对环境造成了极大破坏,对其进行监测控制刻不容缓。常用的分析检测技术,如高效液相色谱(HPLC)、气相色谱(GC)、高效液相色谱-串联质谱(HPLC-MS/MS)等具有高效快速、重现性好、可自动化操作等优点。但对环境样品中抗生素的检测存在样品前处理过程繁琐、检测灵敏度低、实验成本高等问题。结合现有的检测技术发展新型材料,对提高抗生素的检测灵敏度具有重要意义。碳点(CDs)是一种尺寸介于0~10 nm之间的新型纳米材料,具有小尺寸效应、优异的电学和光学性质、良好的生物相容性等优点,已被广泛应用于环境样品中抗生素的检测。该综述对近5年CDs与传感器、色谱分析技术结合检测抗生素的应用进行了总结,并对其发展前景进行了展望。该文总结了CDs与分子印迹传感器、适配体传感器、电化学发光传感器、荧光传感器及电化学传感器相结合,及其在抗生素检测中的应用;对涉及的比率型传感器、阵列传感器等先进分析方法进行了举例评述;对CDs作为色谱固定相分离抗生素进行了阐述。文献表明,CDs结合传感器检测抗生素可有效提高检测灵敏度,但对复杂环境样品中抗生素的检测还面临着构建高选择性传感器、开发新型材料及数据处理等方面的挑战;目前,CDs作为色谱固定相对抗生素的材料分离,仍处于初步研究阶段,分离机理尚不明确,有待进一步深入研究。总之,CDs在环境样品中抗生素的检测方面仍面临一系列问题,随着人们对CDs的深入研究以及各种分析检测技术的不断发展,CDs将会在抗生素等环境污染物的检测中发挥重要作用。

Scavenging organic micropollutants from water with nanofibrous hypercrosslinked cyclodextrin membranes derived from green resources

As a principal constituent of living organisms, water is crucial to sustain life on Earth. However, its pollution by major human activities leading to clean water scarcity is a significant issue. Industrial activities release toxic pollutants, such as textile dyes and polycyclic aromatic hydrocarbons (PAHs), which pollute water resources and endanger the marine ecosystem and human life. To address this issue, we developed a highly effective sorbent platform based on a nanofibrous membrane, comprising hypercrosslinked cyclodextrin networks (HCNs). Cyclodextrins (CDs) are cyclic oligosaccharides with a truncated cone shape featuring a partially hydrophobic cavity interior, which can form complexes with organic micropollutants. The nanofibrous HCN membrane was produced via the electrospinning of highly concentrated CD solutions containing a naturally occurring graphitic acid linker. The thermal crosslinking of the nanofibrous membrane resulted in a robust covalent polymer network of CD macrocycles, which can retain its shape in aqueous and organic solvents. The membrane was produced by exclusively using green resources including a novel natural crosslinker (i.e., graphitic acid), which has not been previously employed for any CD-based materials. Molecular modeling revealed that the crosslinking had a negligible effect on the host–guest complexation of the nanofibrous CD networks. The HCN membrane was used for scavenging textile dyes and PAHs from polluted water, and it demonstrated high sorption performance (Qmax = 692 mg g−1 dye), and excellent reusability upon the application of acidic methanol treatment. The nanofibrous HCN membrane can be used for rapid and efficient scavenging of organic micropollutants in aqueous environments.

Cyclic Oligosaccharides as Active Drugs, an Updated Review.

There have been many reviews of the cyclic oligosaccharide cyclodextrin (CD) and CD-based materials used for drug delivery, but the capacity of CDs to complex different agents and their own intrinsic properties suggest they might also be considered for use as active drugs, not only as carriers. The aim of this review is to summarize the direct use of CDs as drugs, without using its complexing potential with other substances. The direct application of another oligosaccharide called cyclic nigerosyl-1,6-nigerose (CNN) is also described. The review is divided into lipid-related diseases, aggregation diseases, antiviral and antiparasitic activities, anti-anesthetic agent, function in diet, removal of organic toxins, CDs and collagen, cell differentiation, and finally, their use in contact lenses in which no drug other than CDs are involved. In the case of CNN, its application as a dietary supplement and immunological modulator is explained. Finally, a critical structure–activity explanation is provided.

Carbon dot-based nanocomposite: Long-lived thermally activated delayed fluorescence for lifetime thermal sensing

Temperature sensors with unique temperature-dependent luminescent properties have a great advantage to be used as noncontact luminescence thermometers especially in biological applications. To date, most of the photoluminescent materials for temperature sensing are based on the temperature-dependent luminescent intensity or short-lived emission lifetime, which suffer from the interference from excitation power, sample concentration, or background fluorescence. Herein, we report a carbon dot (CD)-based nanocomposite showing distinct long-lived thermally activated delayed fluorescence (TADF) property with the lifetime of 30.85 ms at room temperature and under an air atmosphere. Notably, the TADF emission presents variable long-lived lifetimes under different temperatures, which demonstrates its promising application in lifetime thermal sensing. The interaction between the functional groups of CD and SiO2 matrix by forming Si–O–C bonds plays a key role for the synthesis process, which further improves the confinement of vibrations and rotation and harvests the triplet state efficiently. This work introduces a new perspective to prepare nanothermometers, which opens up the potential application of CD-based materials with long-lived TADF emission in highly sensitive temperature sensing with their convenience and high efficiency.

Multinary copper-based chalcogenide semiconductor nanocrystals: synthesis and applications in light-emitting diodes and bioimaging

Colloidal semiconductor nanocrystals have been extensively used for illumination, displays, bioimaging, and other fields. However, the most extensively used Cd-based nanocrystals are toxic. Recently, non-toxic multinary copper-based chalcogenide semiconductor nanocrystals have been studied intensively. The mostly studied in these materials are ternary Cu–In–S nanocrystals which have large adjustable luminescence range, good luminescence efficiency, and excellent device applications. Therefore, this material has been the most potential candidates to replace Cd-based materials. To date, different synthetic methods have been developed to prepare ternary Cu–In–S nanocrystals, which include hot-injection, non-injection, thermal decomposition, and solvothermal route. In order to enhance the luminescence property, incorporating of Zn2+ or overgrowth of a ZnS shell is the comment ways that researchers often use. This review will introduce the synthesis methods of multinary copper-based chalcogenide semiconductor nanocrystals and their potential applications in quantum-dot light-emitting diodes and bioimaging fields. Finally, the conclusion and prospect are provided.

A co-crystallization induced surface modification strategy with cyanuric acid modulates the bandgap emission of carbon dots.

Along the line of offering surface modification strategies to tune emission properties of carbon dots (CDs), a co-crystallization strategy with cyanuric acid (CA) was developed to modulate the bandgap emissions of CDs and produce highly emissive solid composite CD-based materials. The original blue emission of the CDs changed to a green emission of the CDs@CA crystals, which showed a high photoluminescence quantum yield of 62% and room temperature phosphorescence. The CA molecules firmly bonded to the surface of the CDs and cannot be disrupted by polar solvents or temperature stimuli under ambient conditions, which influenced electron transitions of CDs leading to improved luminescence with excellent thermal stability both in solution and solid states.

Theranostic Carbon Dots with Innovative NIR-II Emission for in Vivo Renal-Excreted Optical Imaging and Photothermal Therapy.

Carbon dots (CDs) with low biotoxicity, high photostability, and well-controlled size are highly desirable imaging agents for optical bioimaging. However, most of the CDs triggered by ultraviolet/blue light present visible/first near-infrared emissions shorter than 820 nm, impairing their imaging applications in vivo by low penetration depth. Hence, developing novel CD-based materials with second near-infrared (NIR-II) emission located in 1000-1700 nm region is an urgent task. Here, a novel NIR-II-emitting CD-based nanoprobe triggered by 808 nm laser is developed. The designed CDs with 900-1200 nm luminescence possess high quantum yield (QY-0.4%) and high biocompatibility, which have proven to be effective probes for in vivo NIR-II bioimaging. Notably, nearly 65% CDs are excreted from mouse urine within 6 h, demonstrating the rapid renal clearance of CDs. Furthermore, the designed CDs also exhibit high photothermal efficiency (30.6%), making them ideal materials for thermal ablation of cancer. Our findings pave the way of designing a multifunctional CD-based theranostic platform for simultaneously integrating the advanced NIR-II bioimaging and photothermal therapy of cancer.

Blue, green, and red full-color ultralong afterglow in nitrogen-doped carbon dots.

Carbon dots (CDs) with tunable emission colors and multiple emission modes are highly desirable in advanced optical anti-counterfeiting. Some pioneering efforts to trigger additional long-lived emission modes, nevertheless, did not perfectly solve the issue of printability and color-tunability in practical applications. Herein, we developed an encapsulating-dissolving-recrystallization route for the synthesis of CD-based anti-counterfeiting inks, and accordingly realized blue, green, and red full-color afterglow emissions from these CD-based inks when printed on paper. The printed inks simultaneously possessed triple emission modes including fluorescence (FL), delayed fluorescence (DF), and room-temperature phosphorescence (RTP), among which the long-lived emissions (DF and RTP) could be selectively activated by using different excitation wavelengths. We believe that the proposed synthetic route in this work may promote the development of multicolor-encoded and multiple-mode-integrated optical anti-counterfeiting systems, and will expand the application of CD-based materials to the fields of sensing, photodynamic therapy and bio-imaging.

Simultaneous removal of five triazole fungicides from synthetic solutions on activated carbons and cyclodextrin-based adsorbents.

In this study, an adsorption-oriented process for the removal of fungicides from polycontaminated aqueous solutions was applied. To remove triazole fungicides from aqueous mixtures of propiconazole (PROPI), tebuconazole (TEBU), epoxiconazole (EPOXI), bromuconazole (BROMU) and difenoconazole (DIFENO), several materials used as adsorbents were compared using batch experiments, namely two conventional activated carbons (ACs) and five nonconventional cross-linked cyclodextrin (CD)-based materials (α-CDP, β-CDP, γ-CDP, αβγ-CDP mixture, and hydroxypropyl-β-CDP). This article presents the abatements obtained. As expected, ACs exhibited the highest levels of triazole fungicide removal: the treatment lowered the five azoles by more than 99%, and adsorption was non-selective. Concerning CD-based materials employed for the first time for the removal of fungicides from polycontaminated aqueous solutions, results were interesting in particular for hydroxypropyl-β-CDP: 1 g of adsorbent placed in 1 L of solution containing 1 mg of each of five triazoles (5 mg in total) was able to remove over half of the fungicide amount (2.97 mg). The order obtained was the following: BROMU << PROPI ≅ EPOXI < TEBU << DIFENO. This indicates that, in the mixture studied, strong competition prevailed among fungicides for the binding sites.