Highly fluorescent nitrogen-doped carbon dots derived from <i>Phyllanthus acidus</i> utilized as a fluorescent probe for label-free selective detection of Fe³⁺ ions, live cell imaging and fluorescent ink

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Aseer, Kanikkai Raja,Perumal, Suguna,Karthik, Namachivayam,Lee, Yong Rok Elsevier 2018 Biosensors & bioelectronics Vol.99 No.-

<P><B>Abstract</B></P> <P>A facile, economical and one-step hydrothermal method is used to synthesize highly durable fluorescent nitrogen-doped carbon dots (FNCDs) by utilizing <I>Phyllanthus acidus</I> (<I>P. acidus</I>) and aqueous ammonia as the carbon and nitrogen sources, respectively. The synthesized FNCDs have an average size of 4.5±1nm and showed bright blue fluorescence under the irradiation of UV-light at an excitation wavelength of 365nm. It exhibits a quantum yield (QY) of 14% at an excitation wavelength of 350nm with maximum emission at 420nm. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy characterizations clearly showed the formation of FNCDs that predominantly consists of nitrogen and hydroxyl groups which can provide more adsorption sites. In addition, the above study reveals the successful bonding of nitrogen with carbon (C–N) in the FNCDs. The synthesized FNCDs with high QY can be used as efficient fluorescent probes for the detection of Fe<SUP>3+</SUP>. Based on the linear relationship between normalized fluorescence intensity and concentration of Fe<SUP>3+</SUP> ions, the prepared FNCDs can be used for label-free sensitive and selective detection of Fe<SUP>3+</SUP> ions in a wide concentration range of 2–25μM with a detection limit of 0.9μM. The present study proves that synthesized FNCDs has durable fluorescence, soluble in water very well and thus act as a promising candidate for the diverse applications such as label-free sensitive and selective detection of Fe<SUP>3+</SUP>, fluorescent ink and cellular imaging with good biocompatibility and low cytotoxicity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FNCDs was successfully synthesized using <I>Phyllanthus acidus</I> by hydrothermal method. </LI> <LI> First time, durable FNCDs was derived from the <I>P. acidus</I> fruit juice with QY of 14%. </LI> <LI> FNCDs were used as a fluorescent probe for lable-free selective detection of Fe<SUP>3+</SUP>. </LI> <LI> FNCDs can be used as a fluorescent ink without any chemical modification. </LI> <LI> FNCDs could offer a multi-colour cell imaging and alternative for fluorescent pens. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis and characterization of graphenated carbon nanotubes on IONPs using acetylene by chemical vapor deposition method

Atchudan, R.,Perumal, S.,Edison, T.N.J.I.,Pandurangan, A.,Lee, Y.R. North-Holland 2015 Physica E, Low-dimensional systems & nanostructure Vol.74 No.-

The graphenated carbon nanotubes (G-CNTs) were synthesized on monodisperse spherical iron oxide nanoparticles (IONPs) using acetylene as carbon precursor by simple chemical vapor deposition method. The reaction parameters such as temperature and flow of carbon source were optimized in order to achieve G-CNTs with excellent quality and quantity. Transmission electron microscopy (TEM) clearly illustrated that the graphene flakes are forming along the whole length on CNTs. The degree of graphitization was revealed by X-ray diffraction (XRD) analysis and Raman spectroscopic techniques. The intensity of D to G value was less than one which confirms the obtained G-CNTs have high degree of graphitization. The optimum reaction temperature for the IONPs to form metallic clusters which in turn lead to the formation of G-CNTs with high carbon deposition yield is at 900<SUP>o</SUP>C. The TEM shows the CNTs diameter is 50nm with foiled graphene flakes of diameter around 70nm. Our results advocate for IONPs as a promising catalytic template for quantitative and qualitative productivity of nanohybrid G-CNTs. The produced G-CNTs with high degree of graphitization might be an ideal candidate for nanoelectronic application like super capacitors and so on.

Electrocatalytic and energy storage performance of bio-derived sulphur-nitrogen-doped carbon

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Parveen, Asrafali Shakila,Lee, Yong Rok Elsevier 2019 Journal of Electroanalytical Chemistry Vol.833 No.-

<P><B>Abstract</B></P> <P>Sulphur and nitrogen-rich carbon layers (S/N-CLs) have been derived successfully <I>via</I> a simple calcination for high energy applications including supercapacitor and electrocatalytic hydrogen evolution reaction (HER). The flexible working electrode was fabricated using thoroughly analyzed S/N-CLs composite as an active electrode energy material for supercapacitor and HER. The S/N-CLs composite shows a higher specific capacitance of 266Fg<SUP>−1</SUP> at a current density of 0.5Ag<SUP>−1</SUP> and a satisfied cycling stability with 84% capacitance retention even after 5000cycles of galvanostatic charge-discharge. On the other hand, the synthesized S/N-CLs composite was used as an electrocatalyst for HER and it exhibits an excellent HER performance with an onset overpotential of −75mV, and a Tafel slope of 73mVdec<SUP>−1</SUP> in 0.5M H<SUB>2</SUB>SO<SUB>4</SUB> aqueous electrolyte. Also, the S/N-CLs composite displayed good stability and strong durability. The high electrocatalytic activity and stability of S/N-CLs composite toward HER due to the active site of a compound which may originate from the heteroatom-functional groups including N and S in the carbon structure. Overall, the high-performance supercapacitors and enhancing HER based on heteroatom-doped carbon structures could be promising in replacing traditional supercapacitors for many electronic devices and electrocatalyst for HER.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Conversion of <I>Magnolia liliiflora</I> into S/N-CLs composite by a simple carbonization </LI> <LI> S/N-CLs delivered a higher C<SUB>s</SUB> of 266Fg<SUP>−1</SUP> at 0.5Ag<SUP>−1</SUP> with a satisfied stability. </LI> <LI> S/N-CLs exhibits an excellent HER performance with a Tafel slope of 73mVdec<SUP>−1</SUP>. </LI> <LI> This is the first attempt in synthesis of S/N-CLs using <I>Magnolia liliiflora</I> flower. </LI> <LI> S/N-CLs will be an alternative for traditional energy storage material and electrocatalyst. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Direct solvothermal synthesis of zinc oxide nanoparticle decorated graphene oxide nanocomposite for efficient photodegradation of azo-dyes

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Shanmugam, Mani,Lee, Yong Rok Elsevier Sequoia 2017 Journal of photochemistry and photobiology Chemist Vol. No.

<P><B>Abstract</B></P> <P>Zinc oxide nanoparticles decorated graphene oxide (ZnO@GO) nanocomposite was successfully prepared using graphene oxide (GO) and zinc oxide nanoparticles (ZnO NPs) as raw materials by simple solvothermal method. The X-ray diffraction pattern, X-ray photoelectron spectroscopic, Fourier transform infrared spectroscopic, and Raman spectroscopic techniques revealed the formation, elemental composition and the purity of ZnO NPs and ZnO@GO nanocomposite. The ZnO NPs were synthesized via simple thermal oxidation, the synthesized ZnO NPs exhibits an excellent near spherical shape with narrow size distribution and mean size of around 20±5nm which is vividly observed from field emission scanning electron microscopic images. The elemental compositions of ZnO@GO nanocomposite which carbon, oxygen and zinc were revealed by XPS and EDX elemental mapping. The ZnO NPs decorated on GO layers were clearly seen in the high resolution transmission electron microscopic images. The photocatalytic activities of the synthesized pure ZnO NPs and ZnO@GO nanocomposite were investigated by photodegradation of azo-dyes includes neutral red (NR), crystal violet (CV), congo red (CR) and methyl orange (MO) under UV-light irradiation. The results revealed that the ZnO@GO nanocomposite exhibited a remarkably higher photocatalytic efficiency compared to pure ZnO NPs. The enhancement of photocatalytic performance was ascribed to the synergistic effect between ZnO NPs and GO layers. Hence, the synthesized ZnO@GO nanocomposite crucial for efficient degradation of dyes such as NR, CV, CR and MO. The synthesized ZnO@GO nanocomposite exhibits a good photocatalytic activity along with good reproducibility of photodegradation, which is applicable for practical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO@GO nanocomposite was successfully synthesized by facile solvothermal route. </LI> <LI> The ZnO@GO nanocomposite showed excellent photocatalytic activity on azo-dyes. </LI> <LI> This photocatalyst achieves a maximum degradation of ∼100% on NR and CV solution. </LI> <LI> This method of synthesis was an affordable and introduced highly active photocatalyst. </LI> <LI> ZnO@GO exhibits a good reproducibility, which applicable for practical applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Betel-derived nitrogen-doped multicolor carbon dots for environmental and biological applications

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Vinodh, Rajangam,Lee, Yong Rok Elsevier 2019 Journal of molecular liquids Vol.296 No.-

<P><B>Abstract</B></P> <P>An innovative, facile, low-cost and one-pot hydrothermal carbonization method was developed for the synthesis of bright fluorescence nitrogen-doped carbon dots (NCDs) using <I>Piper betle</I> (Betel) leaf as a carbon and nitrogen precursor. Various advanced physicochemical characterization techniques have been performed to confirm the structural and optical properties of the resulting Betel-derived NCDs (B-NCDs). The as-synthesized B-NCDs exhibited unique excitation-dependent fluorescence behavior, high fluorescence/photochemical stability, exceptional solubility in hydrophilic solvents like water, and good biocompatibility. On the basis of the astounding optical behavior of B-NCDs, they were utilized as a nanoprobe for determination of Fe<SUP>3+</SUP> ion by the fluorometric method. Notably, this nanoprobe was performed by a linear relationship between the fluorescence intensity and the concentration of Fe<SUP>3+</SUP> ion ranging from 5 to 30 μM with a detection limit as 0.43 μM. Highly selective and sensitive determination of Fe<SUP>3+</SUP> ion was carried out through the fluorescence quenching of B-NCDs due to the resonance energy/electron transfer (RET) mechanism. Besides, the resulting B-NCDs employed as a biocompatible probe in multicolor imaging applications of HCT-116 human colon cancer cells. B-NCDs is not only efficient nanosensor for the determination of Fe<SUP>3+</SUP> ion and biocompatible probe for the multicolor imaging. It also would be a substantial alternative for the traditional fluorescent inks due to its extraordinary fluorescence stability, biocompatibility, pollution-free, and easily washable. In this report for the first time, Betel leaf as carbon and nitrogen source was used to synthesize B-NCDs without adding any chemical reagent. Thus it was applied for diverse analysis field.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel multicolor bright fluorescent B-NCDs was prepared from <I>Betel</I> leaves. </LI> <LI> B-NCDs was highly selective towards Fe<SUP>3+</SUP> by forming a non-fluorescent complex. </LI> <LI> Fe<SUP>3+</SUP> was detected over a concentration range of 0–30 μM with a LOD of 0.43 μM. </LI> <LI> B-NCDs can enter cells and shows multicolor fluorescence with good biocompatibility. </LI> <LI> B-NCDs used as a substantial alternative of the traditional fluorescent inks. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Green synthesized multiple fluorescent nitrogen-doped carbon quantum dots as an efficient label-free optical nanoprobe for <i>in vivo</i> live-cell imaging

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Clament Sagaya Selvam, N.,Lee, Yong Rok Elsevier 2019 Journal of photochemistry and photobiology Chemist Vol.372 No.-

<P><B>Abstract</B></P> <P>In this work, nitrogen-doped carbon quantum dots (N-CQDs) have been synthesized successfully by a simple hydrothermal method and demonstrated its application for multicolor imaging in <I>Caenorhabditis elegans</I> (<I>C. elegans</I>) as an <I>in vivo</I> model. The synthesized N-CQDs were characterized by various physicochemical techniques such as XRD, Raman spectroscopy, ATR-FTIR spectroscopy, XPS, HRTEM, UV–vis spectroscopy, and fluorescence spectroscopy. The synthesized N-CQDs exhibited a strong fluorescence due to the uniform size distribution with nitrogen-containing and oxygen-containing functional groups onto the surface of N-CQDs which induce the excellent dispersibility in aqueous media. The N-CQDs has an excitation-dependent fluorescence behavior and the strongest fluorescence appeared at 411 nm (emission peak position) under the excitation of 340 nm. Also, the N-CQDs displayed a high quantum yield (QY) of 12.5. The fluorescence behaviour of the aqueous N-CQDs suspension retains for a long time up to 1 year. The prolonging fluorescent N-CQDs was utilized as a staining agent for bioimaging and toxicity of N-CQDs on <I>C. elegans</I> that was conducted by killing assay. <I>In-vivo</I> studies suggested that the N-CQDs displayed excellent biocompatibility and successfully used for high-contrast imaging of N-CQDs in living and dead <I>C. elegans</I>. Based on the strongest fluorescence along with excellent aqueous dispersibility and biocompatibility, the green synthesized N-CQDs would be an ideal candidate for many biological applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A strongest multiple fluorescent N-CQDs were synthesized from the <I>P. acidus</I> fruits. </LI> <LI> Synthesized N-CQDs showed low-toxic and were employed for <I>in vivo</I> live-cell imaging. </LI> <LI> The N-CQDs were uniformly stained within the body of the nematodes (<I>C. elegans</I>). </LI> <LI> The live-cell imaging result reveals the usage of N-CQDs in drug delivery. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Green synthesis of nitrogen-doped carbon nanograss for supercapacitors

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Thirukumaran, Periyasamy,Vinodh, Rajangam,Lee, Yong Rok Elsevier 2019 Journal of the Taiwan Institute of Chemical Engine Vol.102 No.-

<P><B>Abstract</B></P> <P>In the present study, a novel N-doped carbon nanograss (NCNG) were synthesized from the used baby-diaper absorbent via carbonization under the argon atmosphere and has been applied as an electroactive material for flexible supercapacitor. The synthesized NCNG display a grass-like morphology with an acceptable degree of graphitization. The surface areas and average pore size of NCNG were 183 m<SUP>2</SUP> g<SUP>−1</SUP> and 3.3 nm, respectively. On the basis of good structural ordering with reasonable surface area, the NCNG was coated on a carbon cloth and studied their electrochemical performance toward the supercapacitors. The obtained quasi-rectangular shaped cyclic voltammetry curves indicate good capacitive behavior of the NCNG. The galvanostatic charge-discharge experimental results showed that the specific capacitance of NCNG was 81 F g<SUP>−1</SUP> at a current density of 0.5 A g<SUP>−1</SUP> with capacitance retention of 95% after 10,000 cycles of charge-discharge. The slow decrements of specific capacitance with the increment of current density indicate superior rate capability of synthesized NCNG. These excellent electrochemical performances of the synthesized NCNG from used (waste) baby-diaper extend their potential applications in various nanoelectronics field. To the best of authors knowledge, first time the NCNG synthesized from the garbage-waste and can extend their synthesis in large-scale.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first time, N-doped carbon nanograss was synthesized using used baby-diaper. </LI> <LI> The synthesized NCNG is good structural ordering with a reasonable surface area. </LI> <LI> NCNG delivered a high specific capacitance with good capacitance retention. </LI> <LI> In addition, NCNG from used baby-diaper extend their synthesis in large-scale. </LI> <LI> Importantly, the waste diaper derived energy storage is alternative clean energy. </LI> </UL> </P>

In-situ green synthesis of nitrogen-doped carbon dots for bioimaging and TiO₂ nanoparticles@nitrogen-doped carbon composite for photocatalytic degradation of organic pollutants

Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Perumal, Suguna,Vinodh, Rajangam,Lee, Yong Rok Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.766 No.-

<P><B>Abstract</B></P> <P>As an efficient photocatalytic titanium dioxide nanoparticles@nitrogen-doped carbon (TiO<SUB>2</SUB> NPs@C) nanocomposite and bright fluorescent with good biocompatible nitrogen-doped carbon dots (N-CDs) were synthesized at once by an affordable hydrothermal method. Physicochemical properties of the synthesized materials were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) and elemental mapping analysis, high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), ultraviolet–visible (UV–vis) spectroscopy and fluorescence spectroscopy. The photocatalytic efficiency of synthesized TiO<SUB>2</SUB> NPs@C nanocomposite was evaluated in the degradation of methylene blue (MB) under UV-light irradiation. The degradation efficiency of TiO<SUB>2</SUB> NPs@C nanocomposite is about 90% when extending the irradiation time to 40 min, the rate constant is 5 times higher than that of bare TiO<SUB>2</SUB> NPs. The augmentation of photocatalytic activity of TiO<SUB>2</SUB> NPs@C nanocomposite was attributed to the synergistic effect between TiO<SUB>2</SUB> NPs and graphene-like carbon within the nanocomposite. The recycling studies were conducted and the photodegradation efficiency of TiO<SUB>2</SUB> NPs@C nanocomposite did not show any significant changes up to three cycles, suggesting that the synthesized photocatalyst has good repeatability and the considerable stability. In addition, the carbon derived from a natural green source possesses the hydroxyl and nitrogen-containing functional groups on the surface which resulting TiO<SUB>2</SUB> NPs @C nanocomposite with high photocatalytic activity. Also, the obtained N-CDs displays almost zero toxicity towards the <I>Candida albicans</I> cells even at high concentrations which can be utilized as a powerful in-vitro label-free fluorescent probe for live cell imaging. Based on their bright with stable fluorescence and cellular imaging with good biocompatibility, N-CDs would offer a great potential for a wide range of applications in the biomedical and clinical applications in the near future.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TiO<SUB>2</SUB> NPs@C composites was prepared from peach fruit by simple hydrothermal process. </LI> <LI> Degradation efficiency of TiO<SUB>2</SUB> NPs@C is >90% within 40 min under UV irradiation. </LI> <LI> Kinetic of TiO<SUB>2</SUB> NPs@C is 5 times faster than that of TiO<SUB>2</SUB> NPs on MB degradation. </LI> <LI> The obtained N-CDs displays the bright fluorescence with good biocompatibility. </LI> <LI> Based on bioactivity, N-CDs would offer some clinical applications in near future. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Green synthesis of nitrogen-doped graphitic carbon sheets with use of Prunus persica for supercapacitor applications

Atchudan, R.,Edison, T.N.J.I.,Perumal, S.,Lee, Y.R. Elsevier BV * North-Holland 2017 Applied Surface Science Vol.393 No.-

Nitrogen-doped graphitic carbon sheets (N-GCSs) were prepared from the extract of unripe Prunus persica fruit by a direct hydrothermal method. The synthesized N-GCSs were examined by high resolution transmission electron microscopy (HRTEM), nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy. HRTEM showed that the synthesized carbon sheets were graphitic with lattice fringes and an inter-layer distance of 0.36nm. Doping with the nitrogen moiety present over the synthesized GCSs was confirmed by XPS, FT-IR spectroscopy, and energy dispersive X-ray spectroscopy elemental mapping. The fruit extract associated with hydrothermal-carbonization method is economical and eco-friendly with a single step process. The resulting carbon sheets could be modified and are promising candidates for nano-electronic applications, including supercapacitors. The synthesized N-GCSs-2 provided a high specific capacitance of 176Fg<SUP>-1</SUP> at a current density of 0.1Ag<SUP>-1</SUP>. This electrode material has excellent cyclic stability, even after 2000 cycles of charge-discharge at a current density of 0.5Ag<SUP>-1</SUP>.

Facile Synthesis of Monodispersed Cubic and Spherical Calcite Nanoparticles in the Presence of Cetyltrimethylammonium Bromide.

Atchudan, Raji,Na, Hyon Bin,Cheong, In Woo,Jool, Jin American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.4

<P>We report the synthesis of monodisperse calcium carbonate (CaCO3) (nano)particles having either a cubic or spherical structure by reacting calcium nitrate with either sodium carbonate or citric acid, respectively, in the presence of cetyltrimethylammonium bromide (CTAB) via the sonication method. For comparison, CaCO3 (nano)particles were synthesized by the same method in the absence of CTAB and also via the standard hydrothermal method using CTAB. The synthesized CaCO3 (nano)particles were analyzed by various physico-chemical characterization techniques such as X-ray diffraction (XRD), Fourier transform infra-red spectroscopy, thermogravimetric analysis, and scanning electron microscopy with energy-dispersive spectrometer. It was found that the CaCO3 (nano)particles were highly pure with high crystallinity and exhibited the calcite polymorph phase as revealed by the XRD analysis. In addition, the analytical results showed that the (nano)particles prepared in the presence of CTAB by the sonication method had high structural ordering and no agglomeration as compared to the (nano)particles prepared by the hydrothermal method. Therefore, our sonication method is a new way to prepare shape-controlled CaCO3 (nano)particles under mild reaction conditions.</P>