CdS QDs Research Articles

Biosynthesis of CdS Quantum Dots Mediated by Volatile Sulfur Compounds Released by Antarctic Pseudomonas fragi.

Previously we reported the biosynthesis of intracellular cadmium sulfide quantum dots (CdS QDs) at low temperatures by the Antarctic strain Pseudomonas fragi GC01. Here we studied the role of volatile sulfur compounds (VSCs) in the biosynthesis of CdS QDs by P. fragi GC01. The biosynthesis of nanoparticles was evaluated in the presence of sulfate, sulfite, thiosulfate, sulfide, cysteine and methionine as sole sulfur sources. Intracellular biosynthesis occurred with all sulfur sources tested. However, extracellular biosynthesis was observed only in cultures amended with cysteine (Cys) and methionine (Met). Extracellular nanoparticles were characterized by dynamic light scattering, absorption and emission spectra, energy dispersive X-ray, atomic force microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Purified QDs correspond to cubic nanocrystals of CdS with sizes between 2 and 16 nm. The analysis of VSCs revealed that P. fragi GC01 produced hydrogen sulfide (H2S), methanethiol (MeSH) and dimethyl sulfide (DMS) in the presence of sulfate, Met or Cys. Dimethyl disulfide (DMDS) was only detected in the presence of Met. Interestingly, MeSH was the main VSC produced in this condition. In addition, MeSH was the only VSC for which the concentration decreased in the presence of cadmium (Cd) of all the sulfur sources tested, suggesting that this gas interacts with Cd to form nanoparticles. The role of MeSH and DMS on Cds QDs biosynthesis was evaluated in two mutants of the Antarctic strain Pseudomonas deceptionensis M1T: megL– (unable to produce MeSH from Met) and mddA– (unable to generate DMS from MeSH). No biosynthesis of QDs was observed in the megL– strain, confirming the importance of MeSH in QD biosynthesis. In addition, the production of QDs in the mddA– strain was not affected, indicating that DMS is not a substrate for the biosynthesis of nanoparticles. Here, we confirm a link between MeSH production and CdS QDs biosynthesis when Met is used as sole sulfur source. This work represents the first report that directly associates the production of MeSH with the bacterial synthesis of QDs, thus revealing the importance of different VSCs in the biological generation of metal sulfide nanostructures.

Novel in-situ radiation construction of thioglycollic acid capped CdS quantum dots functionalized g-C3N4 nanohybrids with superior photocatalytic activity under visible light

Abstract: A novel type of thioglycollic acid (TGA) capped CdS QDs functionalized g-C3N4 nanohybrids was prepared successfully by in-situ electron beam radiation at room temperature. When the radiation dose was chosen to be 10 kGy, the concentration of CdCl2 was 0.5 mmol/L and the optimum ratio of TGA to CdCl2 was 3 : 1 at pH = 9.0, the TGA-CdS QDs/g-C3N4 nanohydrids had the highest degradation rate at the modified TGA-CdS QDs content of 3.0 wt % and the removal rate of TGA-CdS QDs/g-C3N4 on the dye of MO was reached 94.7% in less than 20 min. The introduction of TGA-CdS QDs was confirmed successfully by a series of morphologies and structures of characterization and analysis with UV–vis, FL, Inverted-FL, DRS, FTIR, XRD, XPS, FE-SEM and HR-TEM, etc. After the introduction of TGA-CdS QDs into the surfaces of g-C3N4, the recombination of photo-generated electron-hole pairs can be significantly reduced and the photocatalytic activity and photostability can be also improved. It is favorable to enhance the photocatalytic performance for the photo-generated holes are rapidly transferred to the solution and hindered the photo-corrosion of TGA-CdS QDs.

Synthesis and characterization of Ag doped cadmium sulfide/multi walled carbon nanotubes: Structural, and photocatalysis studies

Silver doped cadmium sulfide as quantum dots/multi walled carbon nanotubes composites were prepared by chemical methods. The prepared nano-samples were characterized by photoluminescence (PL) and UV–Vis spectroscopy, field emission-SEM, Dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET), and X-ray diffraction (XRD). The DLS result of as-prepared samples was indicated the average size of 5.0, 5.5, and 6.0 nm for CdS quantum dots, CdS/MWCNTs, and CdS/MWCNTs nanocomposites, respectively. The band gap values of CdS QDs, CdS/MWCNTs, Ag-CdS/MWCNTs (2:1), Ag-CdS/MWCNTs (1:1) and Ag-CdS/MWCNTs (2:1) were 2.80, 2.75, 2.70, 2.55, and 2.55 eV, respectively. The specific surface area values of CdS QDs, Ag-CdS/MWCNTs, and Ag-CdS/MWCNTs (1:1) were 47.245, 234.591, and 275.365 m2 g−1, respectively. The prepared samples were investigated towards photo-degradation of crystal violet as a dye compound under ultraviolet light illumination. The amount of photo-decomposition activity of the Ag doped CdS/MWCNTs nanocomposites could be substantially raised. The research work result provides an effective method to prepare several nano-photocatalysts with UV light sensitive progress for degradation of dye compounds.

Effects of thiol ligands on the growth and stability of CdS nanoclusters

A DFT calculation of small CdnSn QDs (n = 6) has been achieved in the study of CdS-ligand systems using DFT and TDDFT calculations. We discussed the influence of three thiol ligands, namely, 3-Mercaptopropionic Acid (MPA), Thioglycerol (TG) and 2-Mercaptoethanol (ME), on the size of CdS QDs. In addition, both the carboxyl group of MPA and the hydroxyl group of TG and ME affected the mechanisms of bonding between ligands and the cadmium atom of the cluster. The interaction between CdS QDs and thiol ligands (R–SH) form stable bonds Cd–S. Increasing the number of (R–SH)−Cd bonds using different ligands ensured the good cohesion of the nanoparticle as well as better confinment. Furthermore, TEM and FTIR analyses confirmed the size, shape and morphology calculated using the DFT.

CdS quantum dots supported by ultrathin porous nanosheets assembled into hollowed-out Co3O4 microspheres: A room-temperature H2S gas sensor with ultra-fast response and recovery

With the urgent need to improve societal security, semiconductor-based gas sensors have received substantial attention for their efficiency and accuracy in the detection of harmful gases. However, challenging existed to develop sensors that exhibit both high response and rapid response/recovery rates at room temperature. Herein, we present a simple and energy-efficient room-temperature in situ growth strategy to prepare CdS quantum dots supported by ultrathin porous nanosheets assembled into hollowed-out Co3O4 microspheres (CdS QD/Co3O4 HMSs). XRD, EDX, BET, SEM, TEM and HRTEM analysis confirmed that the interconnected CdS QDs (˜4.5 nm) were well dispersed on the ultrathin porous nanosheet of Co3O4 HMSs. The fabricated CdS QD/Co3O4 HMS sensor exhibited high response (12.7) and ultra-fast response/recovery rates (0.6/1.0 s) to 100 ppm H2S at 25 °C, which is ascribed to high active quantum dots and hollowed-out nanostructure. In addition, the sensor exhibited a low detection limit (1–5 ppm), good reversibility and exceptional long-term stability. This work explores an efficient way to fabricate high-response and ultra-fast response/recovery room-temperature gas sensors by integrating quantum dots with hollowed-out nanostructures.

Fluorescence hydrogel array based on interfacial cation exchange amplification for highly sensitive microRNA detection

Despite the great success of fluorescence sensing array application in bioanalysis, the photo-quenching problem accompanied with high surface fluorophore density has become the bottleneck for its further sensitivity improvement. Herein, a fluorescence polyethylene glycol (PEG) hydrogel array was developed for highly sensitive microRNA detection based on interfacial cation exchange amplification coupled with DNA hybridization chain reaction (HCR). The carboxylate PEG hydrogel array was fabricated on glass slide via photo polymerization and modified with miRNA capture probe, target miRNA binding triggered HCR in hydrogel with biotin labelled DNA probes to generate numerous DNA polymer chains where biotinylated CdS QDs were subsequently conjugated with a streptavidin bridge. Interfacial cation exchange amplification was triggered in hydrogel upon the introduction of Ag+ and Rhod-5N, and abundant Cd2+ was released from CdS to bind with Rhod-5N for substantial fluorescence enhancement. The aqueous-like environment of hydrogel eliminated the fluorescence quenching and simplified experiment process by performing cation exchange reaction at interface with direct result. The linear range for model target miRNA-21 was 1 fM to 500 pM with a detection limit of 0.835 fM. Taking advantage of the nonfouling property of PEG hydrogel, direct quantification of miRNA-21 was achieved from crude cancer cell lysates with a detection limit down to 10 equivalent cells. The expressions of circulating miRNA-21 in clinical serum samples were also assessed with comparable results from RT-PCR. The developed hydrogel array provides a universal platform for highly sensitive fluorescence sensing, and would benefit clinical non-invasive disease diagnosis.

Rational Design of a Coupled Confronting Z‐Scheme System Toward Photocatalytic Refractory Pollutant Degradation and Water Splitting Reaction

AbstractFabricating competent nanoarchitecture photocatalytic systems with desired band edge potential is crucial for effective charge separation that manifolds photocatalytic action. Here, a prototype pristine rational design of all‐solid‐state coupled confronting Z‐scheme (CCZ) system is synthesized by coprecipitation and hydrothermal method. This proof of concept comprises BiVO4 (B) and MgAl layered double hydroxide (L) as photosystem II (PS‐II) whereas CdS quantum dots (QDs, C) as photosystem I (PS‐I). CdS QDs trigger H2 production that subsequently boosts O2 production at PS‐II. Furthermore, this rare CCZ system shows tremendous performance in methyl orange (MO) and tetracycline (TC) degradation. The prepared Z‐scheme photocatalysts are capable of generating 17 350 and 33 000 µmol h−1 g−1 of O2 and H2 under UV light irradiation, which correspond to apparent conversion efficiency of 7.22% and 13.73%, respectively. The catalyst is able to degrade, respectively, 92% and 51% of 20 mg L−1 TC and MO in 1 h. Maximum accessibility of charge carriers at final charge‐separated state appears to be the basic cause in driving the photocatalytic activity efficiently. In spite of their various morphologies, synergistic interaction among C, B, and L can be effectively utilized to trigger various photocatalytic reactions.

Capped cadmium sulfide quantum dots with a new ionic liquid as a fluorescent probe for sensitive detection of florfenicol in meat samples.

The new ionic liquid capped CdS quantum dots (IL-CdS QDs) as a fluorescent probe was successfully synthesized by a hydrothermal method in a one step process and used for the facile and sensitive determination of florfenicol (FLF) in aqueous media. The new ionic liquid 3-(2-[(5-amino-1,3,4-thiadiazol-2-yl)thio]ethyl)-1-methyl-1H-imidazol-3-ium chloride (IL) was synthesized by introducing 5-amino-1,3,4-thiadiazole-2-thiol as a ligand onto the alkyl chain of the 1-chloroethyl-3-methylimidazolium chloride ILs. This task specific ionic liquid reagent was used for the capping of CdS QDs which played the role of recognition element of FLF. The IL-CdS QDs were characterized by Ultra Violet-Visible absorption -spectroscopy (UV-Vis absorption spectroscopy), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Quenching of fluorescence intensity of the IL-CdS QDs was in proportion to the addition of FLF concentration. Under the optimum conditions, the fluorescence intensity ratio of IL-CdS QDs in the presence and absence of FLF versus FLF concentrations gave a linear response according to the Stern-Volmer equation from 0.1 to 20 μg mL-1 (0.3 to 56 μmol L-1) with a limit of detection 0.035 μg mL-1 (0.098 μmol L-1). The developed method was applied to the determination of FLF in fish and chicken meats with satisfactory results. This method revealed some advantages such as high sensitivity, precision and wide linear range to FLF. The proposed method can be utilized for rapid screening the quality of meat products.

One-pot green synthesis of CdS quantum dots using Opuntia ficus-indica fruit sap

A simple and novel one-pot synthesis of CdS, quantum dots from naturally available fruit sap Opuntia ficus-indica was performed. We have investigated a green route for the synthesis of CdS QDs using eco-friendly and naturally renewable Opuntia ficus-indica fruit sap as green template. Synthesized CdS QDs were determined by Fourier transform infrared spectroscopy, UV–visible (323 nm), X-ray diffraction (cubic structure), X-ray fluorescence, Dynamic light scattering (d50 = 9.56 nm), High resolution transmission electron microscopy (Spherical shaped). Overall the present work describes the green synthesis of CdS nanoparticles from Opuntia ficus-indica fruit sap with extrinsic crystallite size control in the quantum confinement range.

One-step electrosynthesis of CdS quantum dots stabilized by babassu oil and luminescent films deposited by DoD technology

The electrochemical synthesis of CdS quantum-dots was carried out in a one-step electrochemical procedure using babassu oil (BO) as stabilizer. The electrochemical reduction of elemental sulfur in DMSO was investigated by cyclic voltammetry, showing the formation of polysulfides and S2−, such results are in agreement to literature. Thus, the CdS-BO electrosynthesis was realized in DMSO solvent and 30 mA constant current in cavity cell. The cadmium and sulfide ions were locally generated by simultaneous oxidation of a cadmium bar (sacrificial anode), and reduction of elemental sulfur in a graphite powder macroelectrode. The CdS-BO quantum-dots showed a UV–Vis absorption band at λmax = 387 nm with symmetrical emission band at λem = 547 nm, with a full width at half maximum (FWHM) of 124 nm. Lauric (C12H24O2, 48.9%) and myristic (C14H28O2, 20.4%) acids were identified as major components of the BO, in addition, 2.4% of free fatty acids were identified in the BO composition by titration, which explains the good stabilization of CdS QDs synthesized. The CdS-BO colloidal system was used as photonic ink and deposited on silica sheets by inkjet printing by drop on demand technology, without waste generation at all stages. The nanoparticles preserved luminescence after printing and drying, showing that the BO promotes an effective stabilization of the quantum dots.

Novel 3D Printed Device for Dual-Signaling Ratiometric Photoelectrochemical Readout of Biomarker Using λ-Exonuclease-Assisted Recycling Amplification.

A ratiometric photoelectrochemical (PEC) sensing strategy was proposed for monitoring of carcinoembryonic antigen (CEA) based on a homemade 3D printing device with dual-working photoelectrodes (PE1 and PE2), coupling λ-exonuclease (λ-Exo)-assisted recycling amplification with CdS quantum dots. Gold nanoparticles-functionalized ZnO nanorods were utilized as PEC substrate for generating initial photocurrent and immobilizing DNA probe. Upon incubation of target with DNA trigger/CEA aptamer-modified magnetic bead (tri/apt-MB), DNA trigger dissociated from magnetic bead and then hybridized with capture probe (cp) on PE1 or opened hairpin probe (hp) on PE2 to form double-stranded DNA (dsDNA). The exonuclease could recognize and cleave two newly generated dsDNA, leading to the release of trigger. The free trigger strand continued to hybridize with the remaining cp/hp, which were cleaved by λ-Exo, and then trigger was released again and restarted next recycle with the λ-Exo. After digestion of λ-Exo, the number of capture probes on PE1 was reduced, and many short DNA fragments were produced on PE2, thereby resulting in the decreasing CdS QDs on PE1 and the increasing CdS QDs on PE2. As a result, it was observed that the ratio value of photocurrents (PE1/PE2) significantly decreased with the increasing CEA. Under optimum conditions, the sensing method showed a good linear relationship toward CEA within the dynamic range of 0.02-10 ng mL-1 and a detection limit of 6.0 pg mL-1. Moreover, the ratiometric PEC sensor exhibited good reproducibility, satisfying stability, and remarkable anti-interference performance, which suggests its promising application prospect to detect target CEA.

CdS quantum dots pre-deposition for efficiency enhancement of quantum dot-sensitized solar cells

Here we report a general study on the effect of various semiconductor sensitizers i.e. CdS, CdSe, CdS/CdSe, and PbS/CdS on the performance of quantum dot sensitized solar cells (QDSCs). The electron life time in the cells is investigated by applied bias voltage decay method. We clearly indicate that the electron life time could be considerably enhanced by CdS pre-deposition in CdS/CdSe QD sensitized cells.The charge transfer properties of cells are investigated by impedance spectroscopy and it is shown that a clear downward shift in TiO2 conduction band take place through CdS QDs sensitizer pre-deposition. According to the results, type and the sequence of QDs deposition has a clear effect on the recombination resistance in cells. Here the efficiency of solar cells was improved to 3.63% by CdS pre-deposition which is more than 25% improvement in comparison to CdSe sensitized cells (2.84%). This general study indicates that tuning the sensitizer type can be systematically used in QDSCs to increase the electron life time and consequently the cells’ performance in a simple and cost effective way.

Construction of Isoenergetic Band Alignment between CdS QDs and CaFe2O4@ZnFe2O4 Heterojunction: A Promising Ternary Hybrid toward Norfloxacin Degradation and H2 Energy Production

The increasing demand for clean water triggers advancement in development of nanomaterials for photocatalytic pollutant degradation. Herein, we report for the first time a CdS QDs decorated p-CaFe2...

Effect of annealing time on optical properties of CdS QDs containing glasses and their application for degradation of methyl orange dye

Borosilicate glass system (SiO2:B2O3:Na2O:ZnO) with the addition of 3 wt% CdS was prepared by conventional melt quench technique. Amorphous nature of glass sample was confirmed from XRD measurement. CdS QDs were grown in the glass matrix using an optimized heat treatment schedule in between glass transition (Tg) and crystallization (Tc) temperature. The phases of CdS QDs were noted by XRD and confirmed by HRTEM. Optical absorption study was carried out to measure the energy band gap and it is found that the energy band gap decreases with an increase in the size of QDs. Size determination was done by optical absorption spectra and match with HRTEM results. This change in the size of QDs was confirmed by PL spectra. The optimized glass sample was used for the degradation of methyl orange (MO) dye.

Multifunctional magneto-fluorescent NiZnFe@CdS core-shell nanostructures for multimodal applications

Magneto-fluorescent nanostructures are promising materials for application in biological fields such as optically tracked targeted drug delivery systems etc, and in the field of electronics and spintronics. Here, a new set of magneto-fluorescent core-shell nanostructures were formed from the Ni-Zn-ferrite as magnetic core and CdS quantum dots as fluorescent semiconducting shell with exceptional physical and chemical properties of individual magnetic core and QDs shell. These magneto-fluorescent nanostructures were prepared to overcome the limitations present in the studied iron oxide based magneto-fluorescent or magneto-plasmon nanostructures in the field. These magneto-fluorescent nanostructures were prepared using two-step process, which includes sol-gel and wet chemical methods. Ni-Zn-ferrites@CdS nanostructures were synthesized for different loadings of ferrite with different sizes of CdS QDs, where 2-mercaptoethanol was used as the stabilizing agent for the controlled growth of CdS QDs size. Ni-Zn ferrites, CdS and core-shell Ni-Zn-ferrite@CdS nanoparticles were investigated for structural, optical and magnetic properties. X-ray studies reveal the structural properties of Ni-Zn ferrite, CdS QDs, and Ni-Zn-ferrite@CdS. The optical properties of prepared nanoparticles were characterized by UV–visible and photoluminescence spectroscopy at room temperature. High-resolution transmission electron microscopy was used to observe the core-shell structure. Vibrating sample magnetometer was used to study the magnetic behavior of the samples at room temperature.

Comprehensive spectroscopy studies of photoelimination process of toxic metals ions from aqueous solution by using CdS and CdS@magnetized powder activated carbon assisted magnetic stir bar.

In this study, a simple and novel photocatalytic tool was proposed and developed for photoelimination of toxic metal ions in aqueous solution. CdS quantum dots capped with thioglycolic acid and CdS @ magnetized powder activated carbon (CdS@MPAC) fixed on magnetic stir bar was constructed and applied for photoelimination of toxic metal ions in aqueous solutions. The production and contribution of hydroxyl (OH) and superoxide (O2-) species generated during photoelimination process were investigated. The photoelimination of Cd(II), Co(II), Cu(II), Mn(II), Ni(II) and Pb(II) metal ions was performed at neutral pH (7.0 ± 0.1) with the same experimental circumstances. Maximum removal efficiency was achieved with 0.360 M of CdS@MPAC under 3.0 h daylight irradiation. Photoelimination mechanisms of Cu2+ with CdS QDs were also investigated. Finally, this method was successfully applied for elimination of toxic metal ions from real sample.

In Vivo-In Vitro Comparative Toxicology of Cadmium Sulphide Quantum Dots in the Model Organism Saccharomyces cerevisiae.

The aim of this work was to use the yeast Saccharomyces cerevisiae as a tool for toxicogenomic studies of Engineered Nanomaterials (ENMs) risk assessment, in particular focusing on cadmium based quantum dots (CdS QDs). This model has been exploited for its peculiar features: a short replication time, growth on both fermentable and oxidizable carbon sources, and for the contextual availability of genome wide information in the form of genetic maps, DNA microarray, and collections of barcoded mutants. The comparison of the whole genome analysis with the microarray experiments (99.9% coverage) and with the phenotypic analysis of 4688 barcoded haploid mutants (80.2% coverage), shed light on the genes involved in the response to CdS QDs, both in vivo and in vitro. The results have clarified the mechanisms involved in the exposure to CdS QDs, and whether these ENMs and Cd2+ exploited different pathways of response, in particular related to oxidative stress and to the maintenance of mitochondrial integrity and function. Saccharomyces cerevisiae remains a versatile and robust alternative for organismal toxicological studies, with a high level of heuristic insights into the toxicology of more complex eukaryotes, including mammals.

Au nanoparticle-decorated TiO2 nanorod array for plasmon-enhanced quantum dot sensitized solar cells

Abstract In present work, Au nanoparticle-decorated TiO2 nanorod array composite structure is designed and fabricated as the working electrode of CdS sensitized quantum dot-sensitized solar cells (QDSSCs). The results reveal that the intensity and range of sunlight absorption, photo-generated carriers transport efficiency and overall photoelectric conversion efficiency (PCE) were significantly enhanced due to followed reasons: Hot electrons of Au NPs excited by plasmon effect can offer extra electrons; plasmonic effect can contribute to the extraction and separation of light-generated electrons; the deposition of Au nanoparticles could effectively optimize the interface between TiO2 nanorod and CdS QDs. As a result, an overall PCE of 3.29% has been obtained, which shows 19.6% enhancement compared with pure TiO2 nanorod photoanode.

Evolution of photovoltaic and photocatalytic activity in anatase-TiO2 under visible light via simplistic deposition of CdS and PbS quantum-dots

Abstract A simple approach to deposit metal chalcogenide-based quantum-dots on TiO2 (anatase) nanoparticles via pseudo-successive ionic layer adsorption and reaction (p-SILAR) was opted to design and investigate the corresponding photoactivity under visible light. We used TiO2/PbS and TiO2/CdS nanocomposites for photocatalysis after which we prepared solar paints from them to put side by side the resultant photovoltaic performance. We developed solar paint type quantum-dot-sensitized solar cells (QDSCs) from TiO2/PbS and TiO2/CdS nanocomposites to divulge electron-hole generation, electron-hole recombination, and resistance against photo-corrosion. TiO2/PbS exhibited higher electron-hole generation than TiO2/CdS owing to its efficient visible light harvesting capability which resulted in higher photocurrent density (JSC) and thus higher power conversion efficiency (PCE) for respective QDSC; however, it had inferior resistance against photo-corrosion. Additionally, the degradation of an azo-based dye (acid orange-56) reflected an effectual increase in the photocatalytic activity of anatase-TiO2 as a result of deposition of PbS and CdS QDs. TiO2/PbS performed better than TiO2/CdS as a photocatalyst under visible light irradiation.

CdS QDs/N-methylpolypyrrole hybrids as fluorescent probe for ultrasensitive and selective detection of picric acid.

Inorganic-organic hybrids are an advanced class of luminescent materials showing great promise for fabrication of highly sensitive and selective optical sensors. In the present study, a novel CdS quantum dots/N-methylpolypyrrole (CdS QDs/NMPPY) hybrid was synthesized via the direct polymerization of NMPPY on L-cysteine capped CdS QD aggregates. A number of characterization techniques including FTIR, DLS, FESEM, UV-vis, and fluorescence spectroscopies were used to study the chemical composition, morphology and optical properties of the resultant QDs/polymer hybrid. The as-synthesized CdS QDs/NMPPY hybrid shows a bright emission at 459 nm under excitation at 367 nm in water. Also the results show the role of sodium dodecyl benzenesulfonate (SDBS) to control the mechanism of synthesis and spectroscopic of the prepared CdS/NMPPY hybrid. Moreover, in this work was reported the direct hybridization procedure without other modification such as ligand exchange and coating. We demonstrated that the hybridization of CdS QDs with NMPPY polymer leads to a significant change in fluorescence sensing properties toward nitroaromatic compounds. Further studies unveiled that the emission of CdS QDs/NMPPY hybrid is strongly and selectively quenched by picric acid molecule with a large Stern-Volmer constant of 843,900 M-1 and an excellent detection limit of 4.6 × 10-7 M. The changes in the UV-vis spectra of picric acid solutions in the presence and absence of CdS QDs/NMPPY hybrid displayed that the fluorescence quenching occurs through a static quenching mechanism. Finally, the proposed CdS QDs/NMPPY sensor was successfully utilized to determine the amount of picric acid in real water samples.