Effect Of Carbon Quantum Dots Research Articles

Effect of carbon quantum dots doping on structural, optical, and antibacterial properties of barium tungstate nanocomposite material

Local bacterial infection remains an increasingly severe threat to human health worldwide, and infection control is still a challenging task. Carbon Quantum Dots (CQSs) and barium tungstate show antibacterial properties. CQDs doped Barium Tungstate (BaWO4) are synthesized by using a hydrothermal route and their optical and antimicrobial activities against the Gram-positive bacteria staphylococcus aureus and optical properties were investigated. The UV–Vis reveals a shift in the bandgap from 3.62 eV to 2.93 eV due to doping of CQDs in BaWO4. The structure of the CQDs/BaWO4 were studied by XRD, which shows CQDs doped BaWO4 samples possess tetragona4 werelite structure with the preferred orientation of (112) identified by XRD at 26° having crystallite size ∼ 31 nm. Nanocomposite BaWO4/CQDs exhibit a spherical-like shape and are composed of Ba, O, W and C according to the design of the experiment. Zeta sizer of CQDs by DLS shows the size of CQDs is 7.65 nm. The FT-IR shows the presence of functional groups in doped material like CC, CO, and COOH bonds which indicate that the C-dots are functionalized with epoxy, carbonyl, hydroxyl, and carboxylic acid groups. Their elemental composition and surface morphology were studied by EDS which shows the percentage variation of CQDs in BaWO4, SEM results show the change in shape of the sample by adding CQDs to BaWO4. The TEM image proves the presence of doped material in the BaWO4. The PL spectra reveals the emission spectra shift towards a higher wavelength and absorption increases. The qualitative analysis shows the antimicrobial activity and enlargement of the inhibition zone and quantitative analysis confirms it.

Biogenic carbon quantum dots from marine endophytic fungi (Aspergillus flavus) to enhance the curcumin production and growth in Curcuma longa L

In this study, we have investigated the effect of carbon quantum dots (FM-CQDs) synthesized from marine fungal extract on Curcuma longa to improve the plant growth and curcumin production. The isolated fungus, Aspergillus flavus has produced a high amount of indole-3-acetic acid (IAA) (0.025 mg g-1), when treated with tryptophan. CQDs were synthesized from the A. flavus extract and it was characterized using ultraviolet visible spectrophotometer (UV–Vis) and high-resolution transmission electron microscopy (HR-TEM). The synthesized CQDs were excited at 365 nm in an UV–Vis and the HR-TEM analysis showed approximately 7.4 nm in size with a spherical shape. Both fungal crude extract (FCE) at 0–100 mg L−1 and FM-CQDs 0–5 mg L−1 concentrations were tested on C. longa. About 80 mg L−1 concentration FCE treated plants has shown a maximum height of 21 cm and FM-CQDs at 4 mg L−1 exhibited a maximum height of 25 cm compared to control. The FM-CQDs significantly increased the photosynthetic pigments such as total chlorophyll (1.08 mg g−1 FW) and carotenoids (17.32 mg g−1 FW) in C. longa. Further, antioxidant enzyme analysis confirmed that the optimum concentrations of both extracts did not have any toxic effects on the plants. FM-CQDs treated plants increased the curcumin content up to 0.060 mg g−1 by HPLC analysis. Semi quantitative analysis revealed that FCE and FM-CQDs significantly upregulated ClCURS1 gene expression in curcumin production.

Economic and Performance Analysis of Modified Solar Distillation System Coupling Different Integrations Using Carbon Quantum Dot Nanoparticles: Generalized Thermal Model

Abstract Clean drinking water and electricity production utilizing non-conventional sources of energy is the global demand for sustainable development. Ultrafast heat transfer fluids have delivered impressive results in photovoltaic (PV)-integrated solar thermal systems, in recent times. Efforts have been made for the productivity and electricity augmentation of solar still equipped with helically coilled heat exchanger and coupled with different integrations, viz., (a) partially covered N-photovoltaic thermal compound parabolic concentrator (N-PVT-CPC), (b) partially covered N-photovoltaic thermal flat plate collector (N-PVT-FPC), (c) N-FPC-CPC, and (d) N-flat plate collector (N-FPC). System design has also been modified by adding a roof-top semi-transparent PV module and built-in passive copper condenser (circulation mode), and effect of carbon quantum dots (CQDs) water-based nanofluids, nanoparticles volume concentration, and packing factor (βc) of the PV module has been studied by developing generalized thermal modeling of the system (special cases). Overall, 41.1%, 21.52%, 22.01%, and 10.01% rise in evaporative HTCs is observed in FPC-CPC, PVT-CPC, FPC, and PVT-FPC integrations, respectively. Thermal exergy is found to be higher for FPC-CPC integration, and it follows the enhancement order as FPC-CPC (max-0.147 kW) > PVT-CPC (0.088 kW) > FPC (0.038 kW) > PVT-FPC (0.028 kW). In reference to the base fluid, significant enhancement in the daily productivity is observed for FPC-CPC (10.9%) and PVT-CPC (5.16%) integrations using CQD-NPs. The production cost of potable water has also been estimated for all the cases for n = 30 and n = 50 years life span and i = 4% and 8% interest rates, and it is found to be the lowest (0.014 $/L) for FPC-CPC integration using CQD-NPs (n = 30 years, i = 4%).

Effect of carbon quantum dots’ surface functional groups on tribological performance of polyethylene glycol

Nano additives play an important role in improving the lubricating properties and enhancing the bearing capacity of lubricants. However, traditional nano-additives contain harmful elements such as heavy metals, sulfur, phosphorus, which have a non-negligible impact on the green production of modern industry. In this study, four kinds of carbon quantum dots (CQDs) were prepared by hydrothermal synthesis method, namely CQDs, amino modified CQDs (CQDs-NH2), alkyl modified CQDs (CQDs-CH3), and hydroxyl modified CQDs (CQDs-OH). The microscopic morphology, chemical structure and luminescence of CQDs were characterized. The effects of four kinds of CQDs additives on the tribological properties of polyethylene glycol (PEG) were studied. The results showed that compared with PEG, the average friction coefficient and wear volume of PEG containing 3% CQDs-OH decreased by 60.50% and 95.05%, respectively. A composite protective film containing carbon, nitrogen, FeO, Fe2O3 forms on the worn surface, due to the end hydroxyl group of CQDs-OH has good adsorption. In addition, after 3 months of dispersion experiment, the PEG containing 3% CQDs-OH showed the best dispersion stability, and the antifriction effect was still better than that of pure PEG. Therefore, CQDs-OH is a new type of environmentally friendly lubricating additive with great potential.

Silver nanoparticles coated cellulose-based flexible membrane with excellent UV resistance, high infrared reflection and water resistance for personal thermal management

Designing of a green and multifunctionally integrated cellulose-based flexible wearable material with personal thermoregulation, water and ultraviolet (UV) resistance is essential for the development of personal thermal management and smart textiles. Herein, a hydrophobic silver nanoparticles cellulose-based membrane (H-AgNPs/CEPCM) was prepared through simple solution blending, spin-coating process and chemical vapor modification. The prepared membrane exhibited excellent UV resistance due to the synergistic effect of carbon quantum dots (CQDs) as well as UV-absorbing functional groups. The spin-coated AgNPs layer with high infrared reflectivity has great radiant insulation, and temperature was reduced by 3.4 °C compared with H-CEPCM in indoor environment. Furthermore, the mechanical properties of H-AgNPs/CEPCM were significantly improved by the introduction of amide and ether bonds, as well as a large number of hydrogen bonds. This led to a tensile strength of 23.21 MPa and an elongation at break of 16.57 %, while also providing water resistance. Additionally, the H-AgNPs/CEPCM exhibited outstanding thermal stability and hydrophobicity. This work may provide a feasible and promising strategy for the construction of multifunctional integrated cellulose membrane materials for radiant insulation, outdoor textiles and novel UV protection applications.

Neglected negative effect of carbon quantum dots (CQDs) entering the ocean on marine organisms living in different water layers

Carbon quantum dots (CQDs) are well dispersed in water, but their potential risks in the marine environment have not been described. This study characterized CQDs and investigated their biological effects (including growth, photosynthesis and behavioural changes) in three marine organisms living in different water layers (the surface phytoplankton Phaeodactylum tricornutum and zooplankton Artemia salina and the benthic coral Zoanthus sp. at the bottom). The results showed that over 78 % of CQDs were suspended in seawater after 96 h. The biomass and photosynthesis of P. tricornutum were significantly affected, with a maximum reduction of 89.49 % in algal cells. CQDs accumulated in the intestinal tract of A. salina, reducing grazing and filtration rates by up to 71.88 % and 89.46 %, respectively. In contrast, CQD exposure had irreversible effects on the tentacle expansion behaviour of Zoanthus sp. This study helps clarify the environmental effects and ecological risks associated with the release of CQDs into the ocean.

Effect of carbon quantum dots and Zn2+ ion on perovskite solar cells

Perovskite solar cells (PSCs) have a great attention due to their remarkable performance and a high-quality perovskite film is necessary to achieve high power conversion efficiency (PCE). The effect of carbon quantum dots (CQDs) and Zn2+ ions on perovskite layer of methyl ammonium lead iodide (MAPbI3) was investigated. The optical, structural, and morphological properties of perovskite films with different Zn2+ ratios and CQDs contents were investigated. It was observed that 1% ZnCl2 /0.05 mg/mL CQDs perovskite film composed of uniform grains distribution, complete surface coverage with negligible pinholes, and a larger grain size of 1.8 μm. In addition, it was found that increasing CQDs contents to 0.1 and 0.25 mg/mL enlarged the grain size to ~ 4.2 μm. Moreover, the incorporation of CQDs enhanced crystallinity and grain size. Consequently, these improvements were reflected on the solar cell performance and the efficiency of PSCs with additive of 1% ZnCl2-0.05 mg/mL CQDs was improved from 4.21 to 8.08%.

Improvement of photostability and thermal stability of PVC by carbon quantum dots loaded on TiO2

AbstractTitanium dioxide (TiO2) has a strong oxidation effect when absorbing ultraviolet light. Therefore, when TiO2 is used as a light stabilizer in polyvinyl chloride (PVC), it will cause the photodegradation of PVC. Herein, carbon quantum dots (CQDs) coated TiO2 composite (TiO2@CQDs) was prepared by a one‐step hydrothermal method. The prepared TiO2@CQDs were characterized by transmission electron microscopy (TEM), UV–Vis spectroscopy, X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD). The photostability of PVC film containing TiO2@CQDs was investigated via photodegradation conductivity test, weight loss rate test, and ultraviolet aging test. Due to the down‐conversion effect of CQDs under ultraviolet light, its existence can alleviate the photoaging of PVC. In addition, the thermal stability of PVC containing TiO2@CQDs was studied by conductivity tests and oven thermal aging tests. The presence of CQDs significantly improved the thermal stability of PVC. Meanwhile, the HCl absorption capacity of CQDs could reach 30.8 mg/gcat. According to the DFT calculations, this high absorption capacity is attributed to the HCl immobilization effect via forming hydrogen bonds between HCl and the keto oxygen, carboxyl keto oxygen in CQDs. The hydroxyl group in CQDs could also combine ZnCl2 by forming a coordination bond.

Effect of carbon quantum dots derived from extracts of UV-B-exposed Eclipta alba on alcohol-induced liver cirrhosis in Golden Hamster.

The Eclipta alba plant is considered hepatoprotective, owing to its phytoconstituents wedelolactone. In the current study, effect of elevated ultraviolet-B (eUV-B) radiation was investigated on biochemical, phytochemical, and antioxidative enzymatic activities of E. alba (Bhringraj) plant. The UV-B exposure resulted in an increase in oxidative stress, which has caused an imbalance in phytochemical, biochemical constituents, and induced antioxidative enzymatic activities. It was observed that the UV-B exposure promoted wedelolactone yield by 23.64%. Further, the leaf extract of UV-B-exposed plants was used for the synthesis of carbon quantum dots (CQDs) using low cost, one-step hydrothermal technique and its biocompatibility was studied using in vitro MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay on HepG2 liver cell line. It revealed no toxicity in any treatment groups in comparison to the control. Both CQDs and leaf extract were orally administered to the golden hamster suffering from alcohol-induced liver cirrhosis. In the morphometric study, it was clearly observed that a combination of UV-B-exposed leaf extract and synthesized CQDs delivered the best result with maximum recovery of liver tissues. The present study reveals the positive impact of UV-B exposure on the medicinally important plant, increased yield of wedelolactone, and its enhanced hepatoprotective efficacy for the treatment of damaged liver tissues.

An optimization strategy for photo-Fenton-like catalysts: Based on crystal plane engineering of BiVO4 and electron transfer properties of 0D CQDs

Herein, we report a novel Cu2(OH)3 F/CQDs-BiVO4 composite photo-Fenton-like system, which used BiVO4 and Cu2(OH)3F as electron donor and acceptor, respectively, and achieved efficient electron transfer between them through the electron bridging effect of Carbon quantum dots (CQDs). The material exhibited excellent ciprofloxacin (CIP) removal efficiency in the photo-Fenton-like coupled system. Cu2(OH)3 F/CQDs-BiVO4 had an incredibly fast response rate, eliminating 98.1% of CIP from the solution in just 1 h, according to the reaction kinetics. Exploratory tests proved that the catalyst kept up a sufficient level of activity across a wide pH range of 3–11 and in the presence of various anions. The activity, morphology, and crystal structure of the samples did not appreciably alter after five recycles. Finally, a possible reaction mechanism was also proposed based on the band structure, position and reaction species.

Ratiometric electrochemiluminescence lab-on-paper device for DNA methylation determination based on highly conductive copper paper electrode

Herein, a ratiometric electrochemiluminescence (ECL) lab-on-paper platform, based on enhancing effect of the N-(4-aminobutyl)-N-ethylisoluminol-functionalized glutathione-coated cobalt/gold bimetallic nanoclusters (GCAL) and quenching effect of carbon quantum dots (CQDs), as well as benefiting from high conductivity copper paper electrode, was developed to achieve accurate and sensitive analysis of DNA methylation. Concretely, due to one-to-multiple amplification effect, one target DNA could initiate the formation of supersandwich structure with multiple signal probes labeled with GCAL. Thus, the GCAL signal enhancement effect was realized. Simultaneously, multiple signal probes are connected to hinder the electron conduction rate on the electrode surface, which results in the quenching of CQDs signal. With the method proposed here, wide linear relationship in the range of 1 fM to 10 pM with a low detection limit of 0.27 fM for sensitive detecting methylated DNA was achieved. It is believed that this work provided a rapid, low-cost and stabilized method for specific determination of methylated DNA, and the immediate detection of cancer in the clinic will become possible in the future.

In-situ one-step synthesis of porous monolayer carbon nitride nanosheets doped with carbon quantum dots for photocatalytic degradation of Meloxicam

The energy storage and upconversion effect of carbon quantum dots (CQDs) could improve the photocatalytic efficiency of materials. In this study, a visible-light-driven photocatalyst, CQDs-doped carbon nitride nanosheets composite (CNS/CQDs) was in-situ synthesized by the thermal stripping of carbon nitride bulk (CNB). The as-prepared CNS/CQDs photocatalyst was systematically characterized and applied to the removal of Meloxicam (Mel) in water. The results showed that the introduction of CQDs could improve the visible light utilization of the carbon nitride. Mel (50 mL, 10 mg L−1) was degraded by 99.60% in 45 min with CNS/CQDs (20 mg). The stability and recycling experiments showed that CNS/CQDs could maintain high photocatalytic activity under complex matrix and multiple cycles. This work will provide a new attempt to synthesize the CQDs doped photocatalytic materials for the effective removal of organic pollutants in water under visible light.

Morphology-engineered carbon quantum dots embedded on octahedral CdIn2S4 for enhanced photocatalytic activity towards pollutant degradation and hydrogen evolution

In recent years, carbon quantum dots (CQDs) and CdIn2S4 have considered as the representatives of the most potential photocatalysts applied in the field of photocatalysis for efficiently solving energy shortage and environmental pollution. In this work, a novel CQDs hybridized CdIn2S4 (CQDs/CIS) heterostructure with 2D nanosheet/3D nanooctahedra morphology was successfully fabricated by a simple in-situ solvothermal method. Most interestingly, the morphology of hybrid gradually evolved from 3D octahedron to 2D nanosheet with the increase of CQDs. This unique 2D/3D structure and synergistic effect between CQDs and CdIn2S4 increased the multi-dimensional active reaction sites and enhanced the quantum yield and the separation efficiency of photogenerated electron pairs. Therefore, CQDs/CIS hybrids showed excellent photocatalytic activities of H2 generation, RhB and TCH degradation. Especially, CQDs/CIS-3 heterostructure presented the highest photocatalytic efficiency and its hydrogen generation activity (956.79 μmol g−1 h−1) was 7.57-fold improvement by contrast with pure CdIn2S4 (126.35 μmol g−1 h−1). Moreover, RhB and TCH degradation rate constants of CQDs/CIS-3 were about 8.14 and 2.32 times higher than those of CdIn2S4, respectively. Furthermore, the effect of CQDs on the evolution of heterostructure morphology and photocatalytic mechanism were also proposed. This research work would offer useful enlightenment for elucidating the affect of CQDs on the morphology evolution and construction of CQDs-based hybrid with excellent performances for H2 production and pollutant removal.

Effect of Carbon Quantum Dots Doping on Structural, Optical and Antibacterial Properties of Barium Tungstate Nanocomposite Material

Effect of Carbon Quantum Dots Doping on Structural, Optical and Antibacterial Properties of Barium Tungstate Nanocomposite Material

Anti-aggregation effect of carbon quantum dots on diabetogenic and beta-cell cytotoxic amylin and beta amyloid heterocomplexes.

Pancreatic islet amyloid deposition is a pathological hallmark of Type 2 diabetes (T2D), contributing to reduced functional β-cell mass. Islet amyloids result not only from the aggregation and fibrillation of human islet amyloid polypeptide (hIAPP), but also from beta-amyloid 42 (Aβ42), the key amyloidogenic peptide linked to Alzheimer's disease. Importantly, Aβ42 and hIAPP aggregates (IAPP:Aβ42) can interact with each other and form some harmful heterocomplex fibrils. While it is well-documented that hIAPP aggregation occurs only when islets are exposed to a diabetic environment, including hyperglycemia and/or elevated concentrations of saturated fatty acids (SFAs), it remains unclear if hIAPP and IAPP:Aβ42 heteromer fibrillations are directly or indirectly triggered by this environment. In this study, we show the interplay between high glucose concentrations and palmitate as the SFA in the aggregation of hIAPP. In addition, we outline that the interaction of hIAPP and Aβ42 leads to the formation of complex protein aggregates, which are toxic to β-cells. Carbon nanocolloids in the form of positively charged carbon quantum dots (CQD-pos) efficiently prevent single amyloid aggregation and the formation of IAPP:Aβ42 heterocomplexes. We provide clear evidence with this study that the diabetogenic environment of islets could directly contribute to the formation of homomeric and heteromeric amyloid aggregates and fibrils in T2D. We also propose carbon nanocolloids as biocompatible nanomaterials for developing innovative therapeutic strategies that prevent the decline of functional β-cell mass.

Carbon quantum dots in hard carbon: An approach to achieving PIB anodes with high potassium adsorption

Potassium ion batteries have become one of the most promising candidates for Lithium batteries replacement. Here we report a carbon quantum dots@hard carbon (CQDHC) composite electrode material for PIBs that was fabricated by a one-step low-temperature pyrolysis process for the first time. Without complicated post-processing steps, the as-obtained CQDHC can be directly used as a negative potassium electrode. The oxygen-rich carbon quantum dots (CQDs) were in-situ synthesized and randomly located in the hard carbon matrix, enhancing the disorder of CQDHC and promoting potassium adsorption. As a result, the initial charge capacity reaches 361 mAhg−1 and maintains a capacity of 237 mAhg−1 (75.7%) after 150 cycles at 100 m A g−1. The CQDHC electrode also shows long-term stable charge-discharge reproducibility and high columbic efficiency (97%). Even though with low surface area, the CQDHC electrode still offers better rate performance than most of hard carbon materials owing to the synergy effect of carbon quantum dots. The detailed, quantitative analysis of the K+ storage process reveals the dual-mechanism in carbon quantum dots@hard carbon. The present study sheds light on using carbon quantum dots to enhance the performance of carbon electrodes in potassium ion batteries.

Effect of carbon quantum dots on the photo‐absorption, photo‐response and photoelectrochemical performance of KNb 3 O 8 film photoelectrode

The KNb3O8 crystals and carbon quantum dots were synthesized via hydrothermal reaction method, their crystal structural and morphological properties were investigated by X-ray diffraction, scanning electron microscope and transmission electron microscope, respectively. The X-ray diffraction patterns of KNb3O8 film on FTO glass (SnO2 conductive glass doped with fluorine) show that the thin KNb3O8 crystals are apt to stack along the [020] direction of KNb3O8 crystal structure. Scanning electron microscope and transmission electron microscope results indicate that most of KNb3O8 crystals have a width of about 0.5 μm and a length of more than 5 μm and the carbon quantum dot has a graphite structure with a size of about 3 nm. The UV-response KNb3O8 thin film electrode was loaded by carbon quantum dots and showed broader photo-absorption characteristic (up to visible light region) and higher photocurrent (a bias of 0.4 V vs SCE), as compared of the pristine KNb3O8 film electrode. In addition, their photo-electrochemical (PEC) performances were also investigated under different light irradiation conditions with an applied potential between −0.4 and 0.7 V versus SCE.

Study on the influence of embedded structure of carbon quantum dots of the organic solar cells with the territory active layer structure of P3HT: PC61BM: CQDs

In this work, carbon quantum dots (CQDs) were inserted into the poly(3-hexylthiophene):(6,6)-phenyl-C61 butyric acid acrylic (P3HT:PC61BM) system as the third component. Therefore, organic solar cells (OSCs) based on the ternary active layer structure of P3HT:PC61BM:CQDs were prepared. The lattice distance of CQDs was performed using transmission electron microscopy (TEM). The excellent fluorescence emission and light absorption of CQDs were characterized by photoluminescence (PL) and UV–vis absorption spectra. The characterization results of atomic force microscope (AFM) and electrochemical impedance spectroscopy (EIS) indicate that the introduction of CQDs in the active layer can improve the performance of the device but not significantly change the properties of the film. The device based on P3HT:PC61BM:CQDs ternary structure obtains a power conversion efficiency (PCE) of 3.32%, which has a 32.8% increase compared to the reference device (2.50%). Besides, the best short-circuit current density attends to 18.9 mA/cm2, which is increased by 25% compared to the reference device. The improvement is attributed to the photoluminescence effect and the multiple exciton generation (MEG) effect of CQDs. This work provides a new method to improve the performance of organic solar cells.

One-pot synthesis of natural amine-modified biocompatible carbon quantum dots with antibacterial activity

In the present study, the thermal decomposition of citric acid in the presence of biogenic amine was used to synthesize four different functionalized carbon quantum dots (CQDs), namely, histamine-(HCQDs), putrescine-(PCQDs), cadaverine-(CCQDs) and spermine-(SCQDs). The thermal decomposition of the precursors resulted in a decrease in stability and the formation of surface amides via a cross-linking process between the carboxyl and amine groups. The deposition of biogenic amines was confirmed by a structural characterization of the synthesized CQDs. The resulting CQDs, with a net zero charge, exhibited excellent stability in environments with different pH values. Through a set of different cytotoxicity tests, the absence of gene mutations, apoptosis, necrosis or disruption in cell membranes revealed the high biocompatibility of the CQDs. The antimicrobial activity of the synthesized CQDs was investigated against different bacterial species (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia). We determined the growth kinetics, production of reactive oxygen species (ROS), cell viability and changes in membrane integrity by scanning electron microscopy (SEM). The minimal inhibitory concentrations (MICs) for S. aureus ranged from 3.4 to 6.9 µg/mL. Regarding E.coli and K. pneumonia, all CQD formulations reduced growth, and the MICs were determined for CCQDs and HCQDs (6.9–19.4 µg/mL). The antibacterial activity mechanism was attributed to the oxidative stress generated after CQD treatment, which resulted in the destabilization of the bacterial membrane. The bacterial permeability to propidium iodide indicated a change in membrane integrity, and the effect of CQDs on the morphology of the bacterial cells was evidenced by SEM.

PMMA Thin Film with Embedded Carbon Quantum Dots for Post-Fabrication Improvement of Light Harvesting in Perovskite Solar Cells.

Perovskite solar cells (PSCs) with a standard sandwich structure suffer from optical transmission losses due to the substrate and its active layers. Developing strategies for compensating for the losses in light harvesting is of significant importance to achieving a further enhancement in device efficiencies. In this work, the down-conversion effect of carbon quantum dots (CQDs) was employed to convert the UV fraction of the incident light into visible light. For this, thin films of poly(methyl methacrylate) with embedded carbon quantum dots (CQD@PMMA) were deposited on the illumination side of PSCs. Analysis of the device performances before and after application of CQD@PMMA photoactive functional film on PSCs revealed that the devices with the coating showed an improved photocurrent and fill factor, resulting in higher device efficiency.