Microwave-assisted Synthesis Route Research Articles

Facile Synthesis of Oxazolidinones as Potential Antibacterial Agents.

An efficient microwave-assisted synthesis route for novel oxazolidinone analogues has been developed. The general synthesis of these compounds began with an L-proline-mediated three-component Mannich reaction between commercially available 3-fluoro-4-morpholinoaniline, aqueous formaldehyde and α-hydroxyacetone. This was followed by a one-step cyclisation to form the core structure of oxazolidinone antibiotics which was subsequently derivatized. The novel compounds were evaluated for their antibacterial activity against M. smegmatis. One of the novel oxazolidinone derivatives 18 a1 produced a MIC of 8 mg/L, comparable with the commercial Rifampicin. The methodology is a useful addition to the field since it can make highly sought-after oxazolidinone derivatives, using cheaper, less harsh commercially available reagents, in a short time and one pot.

Microwave-Assisted synthesis of CuxFe100-x/Carbon aerogel (x = 0, 30, 50, 70) with enhanced Electrocatalytic activity towards oxygen evolution reaction

A simple and efficient microwave-assisted synthesis route was adopted for carbon aerogel (CA)-supported Cu and Fe catalysts for OER in alkaline media. Catalysts were characterized physically by ICP-MS, XRD, TEM, XPS, SEM, and EDX and electrochemically by CV, chronoamperometry, and EIS. The catalyst having the composition of Cu30Fe70/CA showed excellent activity towards OER with low overpotential (345 mV) and Tafel slope (92.5 mV dec−1). Diffusion coefficient (D° = 2.1 × 10−8 cm2 s−1), mass transport coefficient (mT = 2.8 × 10−4 cm s−1), heterogeneous rate constant (k° = 5.7 × 10−4 cm s−1), and electrochemically active surface area (0.0167 cm2) were obtained for Cu30Fe70/CA modified glassy carbon electrode. CV response in the non-faradic region showed that Cdl and electrochemical surface area (ECSA) of Cu30Fe70/CA increased ∼ 34 times compared to Fe/CA. This work suggests that adding up an optimum amount of Cu to the Fe/CA nanocomposite offers a cost-effective and efficient electrocatalyst for OER.

Rapid synthesis of functional carbon dots by microwave: Advanced information security anti-counterfeiting material

Since carbon dots (CDs) exhibit exceptional optical qualities, they have been the focus of much research. Luminescent materials based on CDs are increasingly appearing, but the realization of solid-state matrix-free long-lasting afterglow and white fluorescence remains challenging. In this work, a microwave-assisted synthesis route is used to prepare solid-state white fluorescent CDs with 6 s matrix-free dual (503 nm, 542 nm) delayed fluorescence (DF) afterglow that can be observed by naked eye which uses 1,2,4,5-benzenetetracarboxylic acid (BA) and ethanol as precursors. And polychromatic nitrogen-doped CDs (N-CDs) are prepared using tetraethylenepentamine (TEPA) as nitrogen source, and the solvent controlled synthesis is typical. The solid-state green N-CDs prepared from ethanol (E-CDs) and white fluorescence N-CDs prepared from deionized water (W-CDs) have 3.5 s and 1.2 s (527 nm, 558 nm) visible matrix-free room temperature phosphorescence (RTP) afterglow, respectively. Our work has found (n, π*) structure providing a new strategy for developing CDs as solid-state long-lasting matrix-free afterglow materials and a new reference value for their potential applications in anti-counterfeiting and information encryption.

Effect of Microwave Synthesis Conditions on the Structure of Nickel Hydroxide Nanosheets.

A protocol for rapid, microwave-assisted hydrothermal synthesis of nickel hydroxide nanosheets under mildly acidic conditions is presented, and the effect of reaction temperature and time on the material's structure is examined. All reaction conditions studied result in aggregates of layered α-Ni(OH)2 nanosheets. The reaction temperature and time strongly influence the structure of the material and product yield. Synthesizing α-Ni(OH)2 at higher temperatures increases the reaction yield, lowers the interlayer spacing, increases crystalline domain size, shifts the frequencies of interlayer anion vibrational modes, and lowers the pore diameter. Longer reaction times increase reaction yields and result in similar crystalline domain sizes. Monitoring the reaction pressure in situ shows that higher pressures are obtained at higher reaction temperatures. This microwave-assisted synthesis route provides a rapid, high-throughput, scalable process that can be applied to the synthesis and production of a variety of transition metal hydroxides used for numerous energy storage, catalysis, sensor, and other applications.

Catalytic conversion of GVL to biofuels using Cu and Pt catalysts over microwave-synthesized FAU zeolite

This work aims to develop the microwave-assisted synthesis route for FAU zeolite. The effect of aging and crystallization times, as well as the use of ultrasonication during the synthesis stages, was studied. A highly crystalline, an extended BET surface area (215.45 m2/g), and a hierarchical nanostructure of faujasite zeolite were obtained using a combined microwave-assisted synthesis with an ultrasonication treatment (MOFAU). The resulting zeolites were used as supports for Pt and Cu catalysts, using a novel polyol impregnation method was possible to achieve an adequate metal loading and homogeneous dispersion of the metal. X-ray diffraction (XRD), Scattering and Transmission Electronic Microscopy (SEM and TEM), Temperature-Programed Reduction (TPR), Energy Dispersive X-ray spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS) and N2 physisorption analyses were used to determine the physicochemical properties of the obtained materials. The prepared materials were used in the catalytic transfer hydrogenation (CTH) of gamma-valerolactone (GVL) using formic acid (FA) as H2 source. The synthesized catalysts presented catalytic activity under the described conditions and 2-MTHF was identified as an interest product observing the highest selectivity with the 3%Pt/MOFAU material.

Microwave-Assisted Synthesis of Stretchable and Transparent Poly(Ethyleneglycol-Sebacate) Elastomers with Autonomous Self-Healing and Capacitive Properties.

Introducing functional synthetic biomaterials to the literature became quite essential in biomedical technologies. For the growth of novel biomedical engineering approaches, progressive functional properties as well as the robustness of the manufacturing processes are essential. By using acid-induced epoxide ring-opening polymerizations through catalysts, a wide variety of biodegradable and functionalized biomaterials can be synthesized. Sebacic acid (SA) and poly(ethylene glycol) diglycidyl ether (PEGDGE) are amongst the FDA-approved biocompatible materials. In this study, we focused on the rapid synthesis of caffeine-catalyzed self-healable elastomer via a facile microwave-assisted synthesis route. The elastomer prepared can be used in various applications, including tactile sensors, wearable electronics, and soft robotics. SA and PEGDGE were catalyzed in the presence of caffeine under microwave irradiation followed by crosslinking in vacuo, yielding an elastomeric material. The chemical characterizations of the obtained elastomer were carried out. The resulting material is transparent, highly stretchable, and has capacitive and self-healing properties even at room temperature. The material developed can be easily applied for the aforementioned applications.

Evaluation of the antimicrobial activity of silver nanoparticles obtained by microwave-assisted green synthesis using Handroanthus impetiginosus (Mart. ex DC.) Mattos underbark extract.

We describe here a green method for the preparation of silver nanoparticles (AgNPs), by a microwave-assisted synthesis route using Handroanthus impetiginosus underbark extract, with antibacterial activity. After optimizing the synthesis parameters with a Box–Benhken designed experiment, samples were characterized by powder XRD, TEM, UV-Vis spectroscopy, FTIR and zetametry. Using the overall optimized conditions of synthesis – time of reaction 15 min at 200 °C and plant extract/AgNO3 volume ratio equal to 10% – highly crystalline ∼13.4 nm-sized spherical AgNPs in a well-dispersed colloidal state were obtained. It was also proved that the plant extract compounds act as reductant and capping agents during synthesis to functionalize AgNPs, resulting in a negatively charged surface with high values of zeta potential in a wide range of pH, from acidic to alkaline media. Biological activity tests against Staphylococcus aureus and Escherichia coli and cell viability experiments showed that synthesized AgNPs were not toxic to HaCaT mammalian cells and presented a high efficiency against Gram-positive bacteria (S. aureus). This was associated with the synergistic combination of AgNP silver cores with the capping layer containing natural compounds with antimicrobial properties and considered an alternative to the AgNPs commonly obtained from conventional routes that present antibacterial effectiveness preferentially against Gram-negative strains.

Fast Microwave-Assisted Hydrothermal Synthesis of Pure Layered δ-MnO₂ for Multivalent Ion Intercalation.

This work reports on the synthesis of layered manganese oxides (δ-MnO2) and their possible application as cathode intercalation materials in Al-ion and Zn-ion batteries. By using a one-pot microwave-assisted synthesis route in 1.6 M KOH (MnVII:MnII = 0.33), a pure layered δ-MnO2 birnessite phase without any hausmannite traces was obtained after only a 14 h reaction time period at 110 °C. Attempts to enhance crystallinity level of as-prepared birnessite through increasing of reaction time up to 96 h in 1.6 M KOH failed and led to decreases in crystallinity and the emergence of an additional hausmannite phase. The influence of MnII:OH− ratio (1:2 to 1:10) on phase crystallinity and hausmannite phase formation for 96 h reaction time was investigated as well. By increasing alkalinity of the reaction mixture up to 2.5 M KOH, a slight increase in crystallinity of birnessite phase was achieved, but hausmannite formation couldn’t be inhibited as hoped. The as-prepared layered δ-MnO2 powder material was spray-coated on a carbon paper and tested in laboratory cells with Al or Zn as active materials. The Al-ion tests were carried out in EMIMCl/AlCl3 while the Zn-Ion experiments were performed in water containing choline acetate (ChAcO) or a ZnSO4 solution. Best performance in terms of capacity was yielded in the Zn-ion cell (200 mWh g−1 for 20 cycles) compared to about 3 mAh g−1 for the Al-ion cell. The poor activity of the latter system was attributed to low dissociation rate of tetrachloroaluminate ions (AlCl4−) in the EMIMCl/AlCl3 mixture into positive Al complexes which are needed for charge compensation of the oxide-based cathode during the discharge step.

Microwave irradiation induced UIO-66-NH2 anchored on graphene with high activity for photocatalytic reduction of CO2

Carbon dioxide (CO2), as a kind of the greenhouse gas, was highly desirable to be converted into fuels by using solar energy. Herein, a novel microwave-induced synthesis route was explored for the in-situ growth and assemble of highly dispersed UIO-66-NH2 nanocrystals onto graphene (GR) with the formation of highly active photocatalyst for converting CO2. The as-obtained UIO-66-NH2/GR hybrid exhibited both high activity and selectivity in the photocatalytic reduction of CO2 to formic acid under visible-light irradiation (λ > 410 nm, 300 W Xe lamp). The photo-reduction efficiency of CO2 for UIO-66-NH2/GR was about 11 times of that for the pure UIO-66-NH2, and 2 times of as that for the UIO-66-NH2/GR sample obtained via traditional hydrothermal synthesis. The proposed microwave-assisted synthesis route may produce lots of "super hot spots" (SHS) on the surface of GR. These SHS not only resulted in small UIO-66-NH2 nanocrystals with a high dispersion onto the surface of GR, but also can greatly improve the interaction between UIO-66-NH2 and GR. Such highly dispersed UIO-66-NH2 ultrafine nanocrystals can allow more active surface for both trapping CO2 and enhancing the light absorption capability to generate photogenerated electrons from UIO-66-NH2 frameworks for reducing CO2 molecules. The strong UIO-66-NH2/GR interaction can effectively facilitate the photoelectron-hole separation and inhibit the leaching of UIO-66-NH2 from GR, contributing a high CO2 photo-reduction activity and excellent recyclability. Such work supplied a novel route for constructing strong interaction between MOFs and graphene with the aim at efficiently reducing CO2 under visible-light irradiation. It could also be explored for other applications, including N2 reduction, water-splitting, and solar cells.

Microwave-assisted one-step synthesis of acetate-capped NaYF4:Yb/Er upconversion nanocrystals and their application in bioimaging

Acetate-capped hydrophilic cubic phase NaYF4:Yb/Er upconversion nanophosphors were effectively synthesized in a single step employing a facile microwave-assisted synthesis route by applying relatively low temperatures in a short span of time compared to the conventional synthetic methods. The nanoparticles having a size of about 25 nm exhibit good upconversion luminescence property and can be well dispersed in aqueous solvents as-synthesized. These upconversion nanoparticles were examined for their cytotoxicity and demonstrated to be an effective material for cancer cell imaging using near-infrared radiation.

Biomass-Derived Activated Carbon Supported Fe3O4 Nanoparticles as Recyclable Catalysts for Reduction of Nitroarenes

Highly porous beetroot-derived activated carbons incorporated with well-dispered magnetite nanoparticles (Fe3O4 NPs; average size ca. 3.8 ± 0.5 nm) were fabricated via a microwave-assisted synthesis route. The magnetic Fe3O4@BRAC catalysts so-fabricated were characterized by a variety of diffent physicochemical teniques, viz. XRD, FE-TEM, VSM, gas physisorption/chemisorption, TGA, XPS, Raman, ICP-AES, and FT-IR spectroscopy. The as-prepared catalysts were exploited for heterogeneous-phase reduction of a series of nitroaromatics (RNO2; R = H, OH, NH2, CH3, and COOH) under KOH as a base, isopropyl alcohol acting as a hydrogen donor as well as solvent and also tested with other solvents. The reaction system not only exhibits excellent activity with high anilines yield but also represents a green and durable catalytic process, which facilitates facile operation, easy separation, and catalyst recycle.

Defect dependent optical, electrical and magnetic properties of nanostructured Mn3O4

Nanostructured Mn3O4 sample with an average crystallite size of ∼12 nm was synthesized through a microwave assisted synthesis route. The average particle size obtained from the transmission electron microscopy analysis is 19 nm. The existence of Mn4+ ions at the octahedral sites is evident from the Raman, UV-Visible absorption and X-ray photoelectron spectroscopy analyses. The DC electrical conductivity is larger than that reported for single crystalline Mn3O4 and the conduction mechanism is the polaronic hopping of holes between cations in the octahedral sites. Study of magnetization of the sample reveals an increase in the Curie temperature (55 K) in comparison with that of single crystalline Mn3O4 due to nanoscaling and surface effects. The analysis of field dependent magnetization at different temperatures assuming a modified Langevin relation reveal the presence of magnetically ordered core and surface with canted spin arrangement.

Rapid,Microwave-Assisted Synthesis of a Composite of Mesoporous MnCo2O4 and Reduced Graphene Oxide(RGO) As a High Perfomance Anode for Li- Ion Batteries

Over the last two decades Li-ion batteries (LIBs) have been investigated to improve their electrochemical properties. LIBs have ushered wireless technology and are now employed in large scale applications such as electric vehicles, solar and wind electricity generation systems. The performances of LIBs depend on properties of electrode materials. Since the first commercialization of LIBs by Sony in 1991, graphitic carbons have been used as anode materials. However graphite suffers from challenges like limited capacity, lithium plating at high current densities and formation solid electrolyte interface (SEI). This has motivated researchers to develop alternate anode materials which could deliver high energy and power densities. Cobalt oxide, iron oxide, manganese oxide and tin oxide are some among them. But most of these materials show rapid capacity fade due to low electronic conductivity. Binary metal oxides such as ZnFe2O4, CuCo2O4, ZnCo2O4, ZnMn2O4, NiCo2O4 and MnCo2O4 have shown good capacity upon cycling because of their better electronic conductivity. MnCo2O4, belongs to cubic spinel structure have attracted much attention due to its characteristics inherited from manganese and cobalt based metal oxides. One of the challenging issues in conversion reaction of a bulk electrode material is to maintain structural integrity during electrochemical cycling with associated issues such as volume changes, pulverization, etc., which affect the performance porous materials have been studied widely because of the easy percolation of electrolyte into core of particles which result in high rate capability and also by allowing volume expansion/contraction arising from intercalation/deintercalation of Li+ ions. Using templates become a general approach to synthesize these porous structures. However in most of the cases, the synthesis requires long duration and involves specially designed autoclaves. Here in we report a single step and rapid, microwave-assisted synthesis route to synthesize mesoporous microspheres of MnCo2O4 dispersed with low concentration (≤ 5 wt%) of reduced graphene oxide (RGO). In a typical synthesis, 0.02 g of graphite oxide (GtO) was added to 20 ml of ethylene glycol and sonicated for 20 minutes at room temperature to form graphene oxide (GO) dispersion. 0.5 mmol of Manganese (II)nitrate. tetra hydrate, 1.0 mmol of cobaltous(III)nitrate.hexahydrate and 15 mmol of ammonium bicarbonate were dissolved in 20 ml of ethylene glycol and stirred for 30 minutes to obtain a homogeneous solution. Then this solution was added drop wise to already prepared solution of graphite oxide under sonication. After sonication, solution was taken into 80 ml glass vessel, heated to 200 oC by microwave irradiation in a single mode microwave reactor (2.45 GHz, Discover, CEM, USA) equipped with a pressure sensor, and an optical fibre temperature sensor, and held at the same temperature for 30 minutes. The system was then cooled down to room temperature naturally. The dark grey coloured product was collected by centrifugation and washed several times with distilled water and ethanol, followed by drying at 60 oC overnight. As prepared dark grey powder was heated to 600 oC at an average heating rate 5 oC per minute in a tube furnace under the flow of nitrogen and held at the same temperature for 5 h to convert it into MnCo2O4 and RGO composite. The phase purity and morphology of the final product were studied by XRD, SEM and TEM analysis. The microscopic image (figure.1) shows that mesoporous MnCo2O4 microspheres were attached on to RGO sheets. The charge-discharge profile is shown in Fig. 2. The specific discharge capacities of 841, 801, 832 and 765 mAh g-1 were obtained for 1st, 2nd, 5th and 30th cycles, respectively, at a current density of 100 mA g-1 in the potential range of 0.01 and 3.0 V vs Li/Li+. These values are comparable with the values that were reported previously. Results pertaining to the aforementioned studies including both physical and electrochemical investigations would be presented. Figure 1

Microwave assisted growth of SAPO-34 on β-SiC foams for methanol dehydration to dimethyl ether

SAPO-34 layers were successfully grown on β-SiC foam with medium specific surface-area, using microwave-assisted hydrothermal synthesis method (MAHyS) for applications as a structured catalyst. Preliminary investigations on SAPO-34 phase purity were conducted to select the appropriate concentrations and protocol to grow pure SAPO-34 on SiC foams. SAPO-34/SiC foam composite was obtained via microwave-assisted synthesis route. X-ray diffraction (XRD) was used to confirm the formation of the composite. Microwave irradiation time, number of coating cycles and pretreatment of the SiC support with zeolite precursor and the template solution were studied to optimize the growth and coverage of SAPO-34 crystals on the SiC foam surface. SAPO-34 crystals with cubic morphologies having 7μm average size were obtained after 6h microwave irradiation at 180°C. However, multi coating steps were required to obtain full coverage of SAPO-34 crystals. Template pretreatments of the host material (SiC foams) significantly improved the loading of crystals on the support surface. Full coverage of SAPO-34 on SiC foams was obtained after 3 times of coatings, which is mostly attributed to the template layer formed on the foam surface that induced the heterogeneous nucleation on the support. The SAPO-34/SiC foam structured catalyst exhibited excellent selectivity and stability in methanol dehydration to dimethyl ether, which was carried out in a fixed bed reactor.

Role of mode of heating on the synthesis of nanocrystalline zinc ferrite

In the present work, microwave-assisted coprecipitation route was used for synthesis of nanocrystalline zinc ferrite and results were compared with conventionally prepared zinc ferrite. Synthesis conditions were kept uniform in both cases, except that the mode of heating was changed. The effects of mode of heating on the material properties were studied systematically. Microstructures of both samples were studied by scanning electron microscopy and transmission electron microscopy and the particle size was found to be in the range of 3–4 nm. Particle size distribution in microwave-processed MS-ZnFe2O4 is found to be highly uniform compared to conventionally processed samples (CS-ZnFe2O4). XRD data confirmed the presence of single-phase face-centered cubic structure for both the samples. The XRD data fitted well with Reitveld refinement. The functional groups were analyzed by FT-IR. Local distortions in the structures were studied by FT-Raman spectra of zinc ferrites at room temperature. This study concludes that the microwave-assisted synthesis route reduced the time of reaction by around 23 h and developed uniformly distributed fine-scaled particles. This method has high potential to synthesize other ferrite materials also.

Aqueous Synthesis of Color-Tunable CuInS2/ZnS Nanocrystals for the Detection of Human Interleukin 6

In this Article, we present a facile microwave-assisted synthesis route for the preparation of water-soluble and high-quality CuInS2/ZnS nanocrystals (NCs) with glutathione as the stabilizer. The as-prepared CuInS2/ZnS NCs exhibited small particle sizes (~3.3 nm), long photoluminescence lifetimes, and color-tunable properties ranging from the visible to the near-infrared by varying the initial ratio of Cu/In in the precursors. The low-toxicity, highly luminescent and biocompatible CuInS2/ZnS NCs were applied to cell imaging, showing that they could be used as promising fluorescent probes. Furthermore, the CuInS2/ZnS NCs were used as the signal labels for a fluoroimmunoassay of the biomarker IL-6, showing their great potential for use as reliable point-of-care diagnostics for biomarkers of cancer and other diseases.

Impact of sonication pretreatment on carbon nanotubes: A transmission electron microscopy study

Sonication treatments are commonly used for debundling and dispersing carbon nanotubes (CNTs) in liquid media prior to chemical functionalization. However, this step may lead to the stripping of the outer graphitic layers and the scission of the CNTs, and can therefore have a deleterious effect on the achievable properties of the functionalized CNTs. Thus, knowledge on the structural integrity of the modified CNTs is required to understand its influence on the device performance of hybrid nanocarbon-based composites. Here we report on the impact of a sonication pretreatment on the structure of multiwalled CNTs, and on the role of the induced modifications on the subsequent attachment of ferrimagnetic Fe3O4 nanoparticles. Decoration of the CNTs with Fe3O4 nanoparticles is achieved by a microwave-assisted synthesis route involving the reaction of iron acetylacetonate with 2-pyrrolidinone. Employing a combination of atomic resolution transmission electron microscopy, electron energy-loss spectroscopy, energy-filtered transmission electron microscopy and electron tomography, we provide evidence that significant degradation of the CNT structure takes place during the dispersion process. Moreover we find that the sp2 system is more heavily disrupted at the interface between the CNTs and the surface-deposited nanoparticles suggesting that nucleation of Fe3O4 preferentially occurs at the nanotube defect sites.

Microwave-assisted synthesis of highly fluorescent nanoparticles of a melamine-based porous covalent organic framework for trace-level detection of nitroaromatic explosives

Covalent organic frameworks (COFs) are a new generation of porous materials constructed from light elements linked by strong covalent bonds. Herein we present rapid preparation of highly fluorescent nanoparticles of a new type of COF, i.e. melamine-based porous polymeric network SNW-1, by a microwave-assisted synthesis route. Although the synthesis of SNW-1 has to be carried out at 180°C for 3d under conventional reflux conditions, SNW-1 nanoparticles could be obtained in 6h by using such a microwave-assisted method. The results obtained have clearly demonstrated that microwave-assisted synthesis is a simple yet highly efficient approach to nanoscale COFs or other porous polymeric materials. Remarkably, the as-synthesized SNW-1 nanoparticles exhibit extremely high sensitivity and selectivity, as well as fast response to nitroaromatic explosives such as 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenylmethylnitramine (Tetryl) and picric acid (PA) without interference by common organic solvents, which is due to the nanoscaled size and unique hierarchical porosity of such fluorescence-based sensing material.

Au–Ag nanoparticles as red pigment in ceramic inks for digital decoration

Novel pigments, consisting of Au–Ag mixed nanoparticles, were developed for digital decoration by ink-jet printing of ceramic wares. Special attention was paid to set up a microwave assisted synthesis route, with a low environmental impact, easily transferable to large-scale production. Several suspensions, based on Au, Ag and Au–Ag mixed nanoparticles were prepared, trying to get a core-shell assemblage, and the synthesis parameters like metal concentration, Ag/Au ratio, time, temperature and chelating agent amount were optimized. The suspensions are stable over many months and a total reaction yield, assessed by ICP-AES analysis, was achieved. Particle size, shape, composition and optical properties were measured by DLS, TEM-EDS, XRD and UV–VIS spectroscopy. The so-prepared inks were applied on ceramic tiles simulating the ceramic process and the colour performance, assessed by colourimetry, were expressed in the CIELab parameters.

Microwave-assisted synthesis of surface-passivated doped ZnSe quantum dots with enhanced fluorescence

A microwave-assisted synthesis route is established to prepare ZnSe:Cu and ZnSe:Mn quantum dots (QDs) with efficient surface passivation. The products exhibit over an order of magnitude stronger photoluminescence (PL) than the samples without surface passivation. The PL dynamics for fluorescence enhancement was studied by using time-resolved PL measurement. Considering the ultrafast growth rates (reaction time of ∼25min) and the high quantum yields (over 12%) of the products, our proposed synthesis route suggests a facile method for obtaining various doped QDs, and the synthesized Cu (or Mn) doped ZnSe QDs with greatly improved biocompatibility may find use in biological applications.