Fluorescent Carbon Quantum Dots Research Articles

Fluorescent carbon quantum dots synthesized from coconut shell for the detection of Fe3+ ion

Fluorescent carbon quantum dots synthesized from coconut shell for the detection of Fe3+ ion

Confined Unimolecular Micelles for Directed Self-Assembly of Ultrastable Multiple-Responsive Ratiometric Fluorescent Ultrasmall Nanoparticle Assemblies.

Ultrasmall fluorescent nanomaterials have been widely studied as novel fluorescent probes; however, these nanomaterials are prone to structural damage or aggregation, and the sensitivity and accuracy of most single emission fluorescence probes were very low. Therefore, the controlled synthesis of stable dual-emission ratiometric fluorescence ultrasmall assembly probes still remains a challenge. Herein, star-like polymer unimolecular micelles were utilized as a scaffold template to encapsulate fluorescent ultrasmall carbon quantum dots (CQDs) and gold nanoclusters (AuNCs) via the polymer template directed self-assembly strategy to obtain multiple-responsive ratiometric fluorescent assemblies. The assemblies were ultrastable, well-defined, and nearly monodispersed with controlled size, regular morphology, and pH- and thermal-responsiveness. The assemblies can be applied to realize rapid, sensitive, quantitative, and specific detection of Cu2+ and GSH. Moreover, the convenient rapid real-time detection was realized via the combination of the visualized paper-based sensor, and the multilevel information encryption was also achieved.

Sustainable carbon quantum dots enhanced photoluminescence for bioimaging applications: An in vitro and in silico analysis

This study explores the synthesis and characterization of glucose-based carbon quantum dots (CQDs) for potential applications in the field of photoluminescence. The unique properties of CQDs are investigated, highlighting their distinct features compared to traditional carbon dots. Here, commercially available L-glucose is a precursor that has been chosen as the starting material to produce fluorescent carbon quantum dots (CQDs). The low to high quantum yield CQDs were reduced by chemical reduction method using sodium borohydride and then thiol (L-cysteine) induced for the stabilizer to stabilize rigidified reduced CQDs-L-cysteine (r-CQDs-Cys). The effect of pH and the ligand effect have been investigated for the photoluminescence (PL) studies of r-CQDs-Cys, yielding emission responses that were tuned according to the pH and ligand. The optimized CQDs to r-CQDs-Cys shows the quantum yield (QY) increased from 8.56 % to 42.72 %. The fluorescent QY of the synthesized CQDs investigated for the cytotoxicity test explicates that 90 % of the cells (MCF7) maintain their normal morphology even at higher concentrations of r-CQDs-Cys at 100 µg/mL. This Cytotoxicity test suggests that r-CQDs-Cys are non-toxic biocompatible and the binding energy value −6.8 kcal/mol of the carbon quantum dots was confirmed by in-silico studies. A total of 13 hydrogen bonds, 2 carbon bonds, and one Pi bond were formed during the interaction of the MCF7 cancer cell line with carbon quantum dots. The overall results confirmed that r-CQDs-Cys enhanced QY, fluorescence emission, and superior water solubility of the while compared to others which made them suitable for bio-imaging applications.

A waterborne polyurethane‐based fluorescent tunable carbon quantum dot

AbstractFluorescent tunable materials have potential applications in lighting, display, anti‐counterfeiting, biological probes, and so on. Herein, carbon quantum dots (CQDs) with blue fluorescence (BCDs), and yellow fluorescence (YCDs) were synthesized by solvothermal method using bio‐based citric acid and lignin as carbon sources, respectively. BCDs and YCDs were anchored on polyurethane chains to prepare waterborne polyurethane‐based blue fluorescent carbon quantum dots (BCDs1.0‐WPU) and waterborne polyurethane‐based yellow fluorescent carbon quantum dots (YCDs1.0‐WPU), respectively. Compared with the corresponding BCDs and YCDs, the fluorescence intensity of both BCDs1.0‐WPU and YCDs1.0‐WPU is markedly enhanced, and the emission peaks obviously show a hypochromatic shift. A waterborne polyurethane‐based fluorescent tunable carbon quantum dots (BCDsxYPDs1‐x‐WPU) is prepared by mixing the ratio of BCDs1.0‐WPU and YCDs1.0‐WPU with the RGB method. It is noteworthy that BCDsxYCDs1‐x‐WPU not only achieves a fluent change of fluorescence from blue to yellow but also emits strong white fluorescence (CIE coordinates: X = 0.28, Y = 0.32). The absolute value of the Zeta potential of BCDsxYCDs1‐x‐WPU is greater than 40, indicating good storage stability. Furthermore, the thermal decomposition temperature is above 225 °C, implying good thermal stability. Furthermore, BCDsxYCDs1‐x‐WPU uses water as a continuous phase and has potential applications in environmentally friendly luminescence, anti‐counterfeiting and biological probes.

Onion-like multicolor thermally activated delayed fluorescent carbon quantum dots for efficient electroluminescent light-emitting diodes

Carbon quantum dots are emerging as promising nanomaterials for next-generation displays. The elaborate structural design is crucial for achieving thermally activated delayed fluorescence, particularly for improving external quantum efficiency of electroluminescent light-emitting diodes. Here, we report the synthesis of onion-like multicolor thermally activated delayed fluorescence carbon quantum dots with quantum yields of 42.3–61.0%. Structural, spectroscopic characterization and computational studies reveal that onion-like structures assembled from monomer carbon quantum dots of different sizes account for the decreased singlet-triplet energy gap, thereby achieving efficient multicolor thermally activated delayed fluorescence. The devices exhibit maximum luminances of 3785–7550 cd m−2 and maximum external quantum efficiency of 6.0–9.9%. Importantly, owing to the weak van der Waals interactions and adequate solution processability, flexible devices with a maximum luminance of 2554 cd m−2 are realized. These findings facilitate the development of high-performance carbon quantum dots-based electroluminescent light-emitting diodes that are promising for practical applications.

Lentils/urea as precursors for profound S and N doping of carbon dots for selective sequential determination of Hg(II) and S(II) in food and environmental samples

In this article, we describe a new platform for probing toxic pollutants, namely Hg2+ and S2-, in aquatic environments by tracing the “on–off-on” fluorescence signals of quantum dots. To achieve this, red lentils and urea, as natural precursors, were utilized as sources of S and N doping, respectively, to fabricate blue fluorescent carbon quantum dots, namely, Lentils/urea quantum dots (LUQDs) with good quantum yield and plentiful S-doping. In the present work, the quality-by-design (QbD) strategy was applied to control and select the optimum conditions for the microwave-aided synthesis of the carbon dots. LUQDs exhibit excitation-dependent emissions, where the maximum fluorescence emission was at 360 nm after excitation at 300 nm. During the detection step, the fluorescence of LUQDs is quenched by the incorporation of Hg2+ over the range of 0.50–70.0 μM. Next, S2- reacts with Hg2+, resulting in turning on the fluorescence emission of LUQDs in the range of 10.0–150.0 µM.The method was applied for the detection of both Hg2+ and S2- in tap, sewage, and river waters samples with a recovery rate ranging between 98.96 % and 101.26 %; in addition, Hg2+ was detected in canned Tuna samples with a recovery of 98.70 %. Furthermore, the greenness of the developed method was confirmed through various greenness metrics.

Lateral flow assemblies and allied application of carbon quantum dots derived from cigarette tobacco in biosensing, anticounterfeiting and fluorescent films: Theoretical and experimental overview

The bio-sensing activity of fluorescence based nanoprobes is one of the most significant aspects to scrutinize the analytical pursuance in modern security and lateral flow assays. Herein, potent transmogrification of waste cigarette tobacco into fluorescent carbon quantum dots (CQDs) has been achieved by calcination approach. The waste transformation to CQDs holds diverse benefits, comprising high quantum yield, low toxicity and scale up synthesis. The developed CQDs were able to identify tetracycline with phenomenal selectivity and sensitivity through fluorescence based method. The sensing mechanism was fully explored using Density Functional Theory (DFT) and Molecular docking studies. Governing features comprising tetracycline concentration, interfering studies, and real water analysis on the identification of tetracycline were also investigated. Along with, the prepared CQDs act as colorimetric probe, facilitating the detection of tetracycline with the naked eye. The lateral flow device was constructed for the on-site detection of tetracycline in real water samples. To the best of our knowledge, the present work represents a novel approach to designing CQDs and demonstrates their significant potential for application in anticounterfeiting measures and lateral flow devices. This work holds significant prospective as the prepared CQDs was fully utilized to its maximum usage in developing films and fluorescent anti-counterfeiting applications. Concisely, current work opens up distinctive opportunities for rapid on-site, real-time and visualized surveillance of tetracycline using CQDs prepared with a quite simple green approach.

Commercial Wheat and Oat Flour Derived Fluorescent Carbon Quantum Dots through Sustainable Hydrothermal Synthesis and Their Biological Activities

AbstractIn this study, we utilized processed edible commercial wheat and oat flours to synthesize highly fluorescent carbon dots using green hydrothermal synthesis. The as‐synthesized carbon quantum dots (CQDs) were characterized using UV‐vis spectrophotometry, photoluminescence spectrophotometry, high‐resolution transmission electron microscopy, and Fourier transform infrared spectroscopy. The synthesized wheat‐CQDs (W‐CQDs) and oat‐CQDs (O‐CQDs) had monodispersed spherical shapes with average sizes of 3–8 and 5–10 nm, respectively, and exhibited strong fluorescence intensity and excitation‐dependent photoluminescence. The W‐CQDs and O‐CQDs were highly dispersed in aqueous solutions and exhibited bright green and blue fluorescence, respectively, under UV light (λex=380 and 370 nm). Both CQDs contained abundant functional groups, including amino, hydroxyl, and carboxyl groups, which may play a major role in biological applications. The W‐CQDs and O‐CQDs showed good free‐radical scavenging capacity in the 2,2‐diphenylpicrylhydrazyl (DPPH) and H2O2 assays. The anti‐inflammatory activities of W‐CQDs and O‐CQDs were more effective than that of the standard, with EC50 values of 1.8 and 1.3 mg/mL, respectively, in the protein denaturation assay. Additionally, the CQDs exhibited low cytotoxicity toward NIH3T3 fibroblast and human HeLa cervical cancer cells when treated with a 5‐mg/mL concentration. Therefore, green‐synthesized W‐CQDs and O‐CQDs are easily available, less cytotoxic, and applicable to therapeutic and cell nanocarrier purposes.

PH response mechanism of bifunctional fluorescent carbon quantum dots and application in cancer detection and bioself-targeting imaging

The development of fluorescent probes suitable for lysosome visualisation as well as real-time tracking is crucial because lysosomes play a crucial role in numerous metabolic activities and diseases. In this paper, nitrogen-doped carbon quantum dots (NCQDs) enriched with a large number of hydroxyl, amino, and carboxyl groups were prepared by a simple solvothermal method using tartaric acid and 4-aminosalicylic acid as raw materials. The fluorescence intensity of NCQDs decreased with increasing pH (1–13) due to protonation and deprotonation as well as hydrolysis of surface groups in alkaline environment and detachment of chromophores. This enabled the NCQDs to achieve label-free and rapid visualisation of pH in cells. The disparity in pH levels between cancer cells and normal cells resulted in varying fluorescence brightness of NCQDs observed in these two cells, which enabled the differentiation of cancer cells from normal cells. Most importantly, when NCQDs entered the cell, lysosomes could provide protons for NCQDs, and the protonation of NCQDs' surface groups led to stronger fluorescence after endocytosis of NCQDs in lysosomes. Thus, lysosomal targeted imaging could be achieved without the need to introduce lysosomal-targeted ligands, and NCQDs had a higher biocompatibility and stability compared to commonly used commercial dyes, which made it the ideal choice of lysosomal-targeted fluorescent probes.

Biomass-derived phosphorous-doped carbon quantum dots (P-CQD): An excellent biocompatible material for in-vitro cell imaging

In this work, a simple hydrothermal process was employed to create phosphorous-doped fluorescent carbon quantum dots (P-CQD) from biomass banana stems. The formation of the P-CQDs and the surface functional group was confirmed through a variety of characterization methods, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), (transmission electron microscopy) TEM, (field emission scanning electron microscopy) FESEM, Fourier transform infrared spectroscopy (FTIR), and (ultraviolet–visible) UV–vis spectroscopy. The quantum yield of the synthesized P-CQDs was found to be 15 %. The P-CQDs showed excitation-dependent photoluminescence (PL) emission behaviour possessing a blue fluorescence under UV light. The P-CQDs was utilized for in vitro cytotoxicity effect on Muscle (L6) and Kidney cells (HEK293). The minimum cell viability for the P-CQD was 96.24 %, while the maximum cell viability was approximately 100 % at a concentration of 400 μg/mL. This study suggests that P-CQDs were non-toxic and could be employed for fluorescence-based cell imaging.

A Fluorescence Biosensor Based on Carbon Quantum Dots Prepared from Pomegranate Peel and T-Hg2+-T Mismatch for Hg2+ Detection.

Mercury ions (Hg2+) can cause damage to human health, and thus, the study of the detection of Hg2+ is extraordinarily important in daily life. This work reported a fluorescence biosensor for the detection of Hg2+. The key point of this strategy was that the fluorescence of carbon quantum dots made from pomegranate peel (P-CQDs) was quenched by hemin, and restored after G-quadruplex binding with hemin. The presence of Hg2+ caused thymine (T)-rich DNA fragments to form T-Hg2+-T mismatches, and this change allowed the release of G-quadruplex. G-quadruplex could change the fluorescence of hemin/P-CQDs. P-CQDs exhibited excellent properties through characterization analysis, such as transmission electron microscope, X-ray photoelectron spectroscopy and Fourier transform infrared. This proposed fluorescence detection strategy established the linear ranges of Hg2+ from 1 nM to 50 nM. In conclusion, this simple biosensor had the advantages of strong sensitivity, high selectivity, and low cost for Hg2+ detection in environmental water samples.

Highly fluorescent nitrogen-doped carbon quantum dots prepared using sucrose and urea: Green synthesis, characterization, and use for determination of torsemide in its tablets and plasma samples.

A simple and facile microwave-assisted method was developed for the synthesis of highly fluorescent nitrogen-doped carbon quantum dots (N-CQDs) using sucrose and urea. The produced quantum dots exhibited a strong emission band at 376 nm after excitation at 216 nm with quantum yield of 0.57. The as-prepared N-CQDs were characterized using Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) images, and ultraviolet-visible (UV-visible) spectra. The average particle size was 7.7nm. It was found that torsemide (TRS) caused an obvious quenching of the fluorescent N-CQDs; so, they were used for its spectrofluorometric estimation. An excellent linear correlation was found between the fluorescence quenching of N-CQDs and the concentration of the drug in the range of 0.10 to 1.0μg/mL with limit of quantitation (LOQ) of 0.08 μg/mL and limit of detection (LOD) of 0.027 μg/mL. The method was successfully applied for the assay of the drug in its commercial tablets and spiked human plasma samples, and the results obtained were satisfactory. Complex GAPI was used for greenness assessment of the analytical procedures and the pre-analysis steps. Interference likely to be introduced from co-administered drugs was also studied.

Fluorescent carbon quantum dots with controllable physicochemical properties fantastic for emerging applications: A review

AbstractCarbon quantum dots (CQDs) have emerged as prominent contenders in the realm of luminescent nanomaterials over the past decade owing to their tunable optical properties, robust photostability, versatile surface functionalization and doping potential, low toxicity, and straightforward synthesis utilizing environmentally friendly precursors. In this review, we commence with a concise introduction, presenting both top‐down and bottom‐up strategies for the eco‐friendly synthesis of CQDs. Subsequently, we delve into a comprehensive examination of CQDs' structure and optical characteristics, encompassing their ultraviolet–visible absorption properties, surface confinement effects, and surface state emissions contributing to room‐temperature photoluminescence (PL). This review proceeds to elucidate recent advancements in modification strategies for CQDs, specifically focusing on surface oxidation, passivation, and the incorporation of heteroatoms. These strategies serve to afford control over the physicochemical properties, facilitating the enhancement of PL through the decoration of highly visible‐responsive CQDs. This enhancement is achieved by suppressing the nonradiative recombination of electron‐hole pairs, enabling red/blue shifts in CQDs for the generation of a full‐color emission spectrum, and regulating the band‐gap and surface states to broaden the photoabsorption range. Finally, we offer an overview of the most recent developments in the applications of fluorescent CQDs, emphasizing their utility in biomedicine, fluorescent sensors, lighting, and displays, as well as photocatalysis.

Preparation of Ampicillin-derived CQDs and its Application in the Detection of Phenols in Medicinal Materials

Background: In this study, ampicillin sodium fluorescent carbon quantum dots were prepared by one-step hydrothermal method with ampicillin sodium as the carbon source and urea as the nitrogen source. Methods: The structure of CQDs were characterized by UV-Vis and fluorescence spectrophotometer. The pH, reaction time and ionic strength of phenol detected by N-CQDs were optimized. The optimum experimental conditions were 40 μL ampicillin sodium N-CQDs, 2 mL buffer solution with pH 8.0, and the reaction time was 6 min. Results: Through the detection of fluorescence spectrophotometry, p-nitrophenol had obvious fluorescence quenching phenomenon on ampicillin sodium N-CQDs, and the detection limit was 75 nM. It was used in the standard addition experiment of actual samples, and the recovery rates were more than 85%. Conclusion: Therefore, the N-CQDs could be used as fluorescent probe to analyze the content of p-nitrophenol in the actual environment.

Comprehensive Overview of Controlled Fabrication of Multifunctional Fluorescent Carbon Quantum Dots and Exploring Applications

AbstractIn recent years, carbon dots (CDs) have garnered increasing attention due to their simple preparation methods, versatile performances, and wide‐ranging applications. CDs can manifest various optical, physical, and chemical properties including quantum yield (QY), emission wavelength (Em), solid‐state fluorescence (SSF), room‐temperature phosphorescence (RTP), material‐specific responsivity, pH sensitivity, anti‐oxidation and oxidation, and biocompatibility. These properties can be effectively regulated through precise control of the CD preparation process, rendering them suitable for diverse applications. However, the lack of consideration given to the precise control of each feature of CDs during the preparation process poses a challenge in obtaining the requisite features for various applications. This paper is to analyze existing research and present novel concepts and ideas for creating CDs with different distinct features and applications. The synthesis methods of CDs are discussed in the first section, followed by a comprehensive overview of the important properties of CDs and the modification strategy. Subsequently, the application of CDs and their requisite properties are reviewed. Finally, the paper outlines the current challenges in controlling CDs properties and their applications, discusses potential solutions, and offers suggestions for future research.

The Brown Sugar Mediated Carbon Quantum Dots as a Novel Fluorescence Sensor for Sensitive Detection of Gentamicin and Its Application in Foods.

In this work, a novel fluorescence sensing strategy was proposed for the detection of gentamicin based on fluorescent carbon quantum dots (CQDs) and gold nanoparticles (AuNPs). Herein, the CQDs were green-synthesized for the first time via a one-step hydrothermal method utilizing brown sugar as the precursor. In the presence of citrate-stabilized AuNPs, the fluorescence of CQDs was quenched efficiently. Gentamicin, on the other hand, had a higher affinity for AuNPs and was able to compete with CQDs for a preferential binding to AuNPs, which ultimately led to the aggregation of AuNPs and freeing of CQDs in solution, causing the fluorescence recovery of CQDs. Based on the above phenomenon, the concentrations of gentamicin could be ascertained by detecting the variations in fluorescence intensity of CQDs. This sensing strategy exhibited excellent selectivity in various antibiotics. At the same time, the method displayed outstanding sensitivity for gentamicin, which was successfully applied to real samples detection.

Synthesis of fluorescent carbon quantum dots from Manihot esculenta waste peels for nonlinear optical and biological applications

The synthesis of carbon quantum dots using cassava (Manihot esculenta) waste peels by simple hydrothermal method. Carbon quantum dots were studied using PXRD, and HRTEM analysis, signifying an amorphous graphite carbon structure. The carbon quantum dots have two absorption peaks in the UV–vis spectrum, around 272 and 304 nm which lead to the π–π* and n–π* transitions. The produced CQDs exhibit excitation dependent fluorescence characteristics, with a fluorescence quantum yield of 4.664% at an excitation wavelength of 330 nm. The CQDs revealed a white light emitting diode with the Commission Internationale d'Eclairage (CIE) coordinates (0.35, 0.35). The nonlinear optical absorption 0.294×10−4 (cm/W), nonlinear refractive index 1.8138×10−8 (cm2/W), and third-order NLO susceptibility 5.5 × 10−6 (esu) were calculated using Z-Scan analysis. The synthesized CQDs were utilized for their antibacterial activity used S. aureus (23 mm), B. cereus (33 mm), E. coli (43 mm), and P. aeruginosa (30 mm) as harmful microbes. Our results suggest that Manihot esculenta waste peels CQDs have potential for application in NLO devices, optical switching, and pharmaceuticals.

Development of a highly sensitive fluorescent probe using Delonix regia (Gulmohar) tree pod shell for precise sarcosine detection in human urine samples: advancing prostate cancer diagnosis

We designed a highly sensitive fluorescent sensor for the early detection of sarcosine, a potential biomarker for prostate cancer. This sensor was based on surface-cobalt-doped fluorescent carbon quantum dots (Co-CD) using a FRET-based photoluminescent sensing platform. Blue luminescent carbon quantum dots (CQD) were synthesised through a hydrothermal approach, utilizing Delonix regia tree pod shells. Cobalt was employed to functionalize the CQD, enhancing the quantum-entrapped effects and minimizing surface flaws. To optimize Co-CD preparation, we employed a Box-Behnken design (BBD), and response surface methodology (RSM) based on single-factor experiments. The Co-CD was then used as a fluorescent probe for selective Cu2+ detection, with Cu2+ quenching Co-CD fluorescence through an energy transfer process, referred to as ‘turn-off’. When sarcosine was introduced, the fluorescence intensity of Co-CD was restored, creating a ‘turn-on’ response. The sensor exhibited a Cu2+ detection limit (LOD) of 2.4 µM with a linear range of 0 μM to 10 µM. The sarcosine detection in phosphate buffer saline (PBS, pH 7.4) resulted in an LOD of 1.54 μM and a linear range of 0 to 10 µM. Importantly, the sensor demonstrated its suitability for clinical analysis by detecting sarcosine in human urine. In summary, our rapid and highly sensitive sensor offers a novel approach for the detection of sarcosine in real samples, facilitating early prostate cancer diagnosis. Communicated by Ramaswamy H. Sarma

Harnessing fluorescent carbon quantum dots from natural resource for advancing sweat latent fingerprint recognition with machine learning algorithms for enhanced human identification.

Nowadays, it is fascinating to engineer waste biomass into functional valuable nanomaterials. We investigate the production of hetero-atom doped carbon quantum dots (N-S@MCDs) to address the adaptability constraint in green precursors concerning the contents of the green precursors i.e., Tagetes erecta (marigold extract). The successful formation of N-S@MCDs as described has been validated by distinct analytical characterizations. As synthesized N-S@MCDs successfully incorporated on corn-starch powder, providing a nano-carbogenic fingerprint powder composition (N-S@MCDs/corn-starch phosphors). N-S@MCDs imparts astounding color-tunability which enables highly fluorescent fingerprint pattern developed on different non-porous surfaces along with immediate visual enhancement under UV-light, revealing a bright sharp fingerprint, along with long-time preservation of developed fingerprints. The creation and comparison of latent fingerprints (LFPs) are two key research in the recognition and detection of LFPs, respectively. In this work, developed fingerprints are regulated with an artificial intelligence program. The optimum sample has a very high degree of similarity with the standard control, as shown by the program's good matching score (86.94%) for the optimal sample. Hence, our results far outperform the benchmark attained using the conventional method, making the N-S@MCDs/corn-starch phosphors and the digital processing program suitable for use in real-world scenarios.

Lemon peel-based fluorescent carbon quantum dots as a functional filler in polyvinyl alcohol-based films for active packaging applications

Carbonation of agro-waste into high-value-added products is becoming a promising strategy for producing functional active materials and for reducing landfills. Carbon quantum dots (CQDs) are of great attention due to their non-toxic, antibacterial, antioxidant, fluorescent, and other functional properties. The current study demonstrated the hydrothermal synthesis of dried lemon peel-based carbon quantum dots (LCQDs) and their incorporation in polyvinyl alcohol for developing active films. The developed LCQDs exhibit excellent fluorescence, antioxidant, and antibacterial activities against S. aureus, B. cereus, S. enterica, L. monocytogenes, and E. coli. Interestingly, as confirmed by FE-SEM and FTIR, LCQDs showed excellent compatibility with PVA-based films. The mechanical and water vapor barrier properties were improved by adding 3% LCQDs to the PVA film, which also resulted in improved UVC (99.9%), UVB (99.9%) and UVA (99.1%) blocking effects. Additionally, PVA film containing 3% LCQDs showed 98.9% radical scavenging activity by ABTS method and was 100% effective against S. aureus and S. enterica. Therefore, 3% LCQDs-incorporated PVA films could have excellent potential as active food packaging materials.