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Szapoczka WK, Olla C, Carucci C, Truskewycz AL, Skodvin T, Salis A, Carbonaro CM, Holst B, Thomas PJ. Ratiometric Fluorescent pH Sensing with Carbon Dots: Fluorescence Mapping across pH Levels for Potential Underwater Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1434. [PMID: 39269096 PMCID: PMC11397204 DOI: 10.3390/nano14171434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Revised: 08/27/2024] [Accepted: 08/31/2024] [Indexed: 09/15/2024]
Abstract
Ocean acidification has become a major climate change concern requiring continuous observation. Additionally, in the industry, pH surveillance is of great importance. Consequently, there is a pressing demand to develop robust and inexpensive pH sensors. Ratiometric fluorescence pH sensing stands out as a promising concept. The application of carbon dots in fluorescent sensing presents a compelling avenue for the advancement of pH-sensing solutions. This potential is underpinned by the affordability of carbon dots, their straightforward manufacturing process, low toxicity, and minimal susceptibility to photobleaching. Thus, investigating novel carbon dots is essential to identify optimal pH-sensitive candidates. In this study, five carbon dots were synthesized through a simple solvothermal treatment, and their fluorescence was examined as a function of pH within the range of 5-9, across an excitation range of 200-550 nm and an emission range of 250-750 nm. The resulting optical features showed that all five carbon dots exhibited pH sensitivity in both the UV and visible regions. One type of carbon dot, synthesized from m-phenylenediamine, displayed ratiometric properties at four excitation wavelengths, with the best results observed when excited in the visible spectrum at 475 nm. Indeed, these carbon dots exhibited good linearity over pH values of 6-9 in aqueous Carmody buffer solution by calculating the ratio of the green emission band at 525 nm to the orange one at 630 nm (I525nm/I630nm), demonstrating highly suitable properties for ratiometric sensing.
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Affiliation(s)
| | - Chiara Olla
- Department of Physics, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy
| | - Cristina Carucci
- Department of Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy
| | | | - Tore Skodvin
- Department of Chemistry, University of Bergen, 5007 Bergen, Norway
| | - Andrea Salis
- Department of Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy
| | - Carlo Maria Carbonaro
- Department of Physics, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy
| | - Bodil Holst
- Department of Physics and Technology, University of Bergen, 5007 Bergen, Norway
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2
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Habteyes TG, Westphal ER, Plackowski KM, Kotula PG, Meyerson ML, White SL, Corbin WC, Ghosh K, Grey JK. Hierarchical Self-Assembly of Carbon Dots into High-Aspect-Ratio Nanowires. NANO LETTERS 2023; 23:9474-9481. [PMID: 37831934 DOI: 10.1021/acs.nanolett.3c02977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
We report a spontaneous and hierarchical self-assembly mechanism of carbon dots prepared from citric acid and urea into nanowire structures with large aspect ratios (>50). Scattering-type scanning near-field optical microscopy (s-SNOM) with broadly tunable mid-IR excitation was used to interrogate details of the self-assembly process by generating nanoscopic chemical maps of local wire morphology and composition. s-SNOM images capture the evolution of wire formation and the complex interplay between different chemical constituents directing assembly over the nano- to microscopic length scales. We propose that residual citrate promotes tautomerization of melamine surface functionalities to produce supramolecular shape synthons comprised of melamine-cyanurate adducts capable of forming long-range and highly directional hydrogen-bonding networks. This intrinsic, heterogeneity-driven self-assembly mechanism reflects synergistic combinations of high chemical specificity and long-range cooperativity that may be harnessed to reproducibly fabricate functional structures on arbitrary surfaces.
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Affiliation(s)
- Terefe G Habteyes
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Eric R Westphal
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - Kenneth M Plackowski
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Paul G Kotula
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - Melissa L Meyerson
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - Stephanie L White
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - W Cody Corbin
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - Koushik Ghosh
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
| | - John K Grey
- Sandia National Laboratories, 1515 Eubank Drive SE, Albuquerque, New Mexico 87185, United States
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3
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Mandal S, Erimban S, Banerjee S, Daschakraborty S, Das P. Elucidating the relationship between red fluorescence and structural dynamics of carbon dots dispersed in different solvents. Phys Chem Chem Phys 2023; 25:23645-23657. [PMID: 37609834 DOI: 10.1039/d3cp02498a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The mechanism of intrinsic fluorescence of carbon dots (CDs), the latest nanomaterial from the carbon family, was supposedly deciphered through multiple theories. However, the much sought-after persistent red emission of CDs as a foreseeable consequence of experiments remains elusive prompting the question of whether tuning of the red emission of CDs is a predictable outcome or a serendipitous coincidence. Herein, we tried to decode the same by exploring Alizarin Red S (ARS)-based red emitting CDs in different solvents with wisely chosen analytical tools. The findings are aptly supported by molecular dynamics studies through an experimental intuition-driven model-building approach. Parallel interception of the CDs with powder X-ray diffraction (pXRD) and photophysical spectroscopic studies revealed an important relationship between the solvent and CDs. Tautomerism, a well-known phenomenon with chemical entities, was found to be operative for CDs that greatly influence the Stokes shift and ultimately the fluorescence outcome. Most importantly, pXRD studies established the turbostratism of the CDs where the well-ordered graphitic structure of CDs gets disrupted with solvent molecules. The extent of such disruption is a function of solvent and CD composition that plays a formidable role in obtaining red fluorescence. Thus, for the first time, we demonstrate that the red emission of CDs is related to its structural integrity and if taken care of could be sustained, a tremendously desirable outcome for relevant applications.
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Affiliation(s)
- Saptarshi Mandal
- Department of Biomedical Engineering, University of Kentucky, Lexington, 40536, USA
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, 801103, India.
| | - Shakkira Erimban
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, 801103, India.
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, USA
| | - Subhrajeet Banerjee
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, 801103, India.
| | | | - Prolay Das
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, 801103, India.
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4
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Arcudi F, Đorđević L. Supramolecular Chemistry of Carbon-Based Dots Offers Widespread Opportunities. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2300906. [PMID: 37078923 DOI: 10.1002/smll.202300906] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/01/2023] [Indexed: 05/03/2023]
Abstract
Carbon dots are an emerging class of nanomaterials that has recently attracted considerable attention for applications that span from biomedicine to energy. These photoluminescent carbon nanoparticles are defined by characteristic sizes of <10 nm, a carbon-based core and various functional groups at their surface. Although the surface groups are widely used to establish non-covalent bonds (through electrostatic interactions, coordinative bonds, and hydrogen bonds) with various other (bio)molecules and polymers, the carbonaceous core could also establish non-covalent bonds (ππ stacking or hydrophobic interactions) with π-extended or apolar compounds. The surface functional groups, in addition, can be modified by various post-synthetic chemical procedures to fine-tune the supramolecular interactions. Our contribution categorizes and analyzes the interactions that are commonly used to engineer carbon dots-based materials and discusses how they have allowed preparation of functional assemblies and architectures used for sensing, (bio)imaging, therapeutic applications, catalysis, and devices. Using non-covalent interactions as a bottom-up approach to prepare carbon dots-based assemblies and composites can exploit the unique features of supramolecular chemistry, which include adaptability, tunability, and stimuli-responsiveness due to the dynamic nature of the non-covalent interactions. It is expected that focusing on the various supramolecular possibilities will influence the future development of this class of nanomaterials.
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Affiliation(s)
- Francesca Arcudi
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, Padova, 35131, Italy
| | - Luka Đorđević
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, Padova, 35131, Italy
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5
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Olla C, Ricci PC, Chiriu D, Fantauzzi M, Casula MF, Mocci F, Cappai A, Porcu S, Stagi L, Carbonaro CM. Selecting molecular or surface centers in carbon dots-silica hybrids to tune the optical emission: A photo-physics study down to the atomistic level. J Colloid Interface Sci 2023; 634:402-417. [PMID: 36542970 DOI: 10.1016/j.jcis.2022.12.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022]
Abstract
In this work, we unveil the fluorescence features of citric acid and urea-based Carbon Dots (CDs) through a photo-physical characterization of nanoparticles synthesized, under solvent-free and open-air conditions, within silica-ordered mesoporous silica, as a potential host for solid-state emitting hybrids. Compared to CDs synthesized without silica matrices and dispersed in water, silica-CD hybrids display a broader emission in the green range whose contribution can be increased by UV and blue laser irradiation. The analysis of hybrids synthesized within different silica (MCM-48 and SBA-15) calls for an active role of the matrix in directing the synthesis toward the formation of CDs with a larger content of graphitic N and imidic groups at the expense of N-pyridinic molecules. As a result, CDs tuned in size and with a larger green emission are obtained in the hybrids and are retained once extracted from the silica matrix and dispersed in water. The kinetics of the photo-physics under UV and blue irradiation of hybrid samples show a photo-assisted formation process leading to a further increase of the relative contribution of the green emission, not observed in the water-dispersed reference samples, suggesting that the porous matrix is involved also in the photo-activated process. Finally, we carried out DFT and TD-DFT calculations on the interaction of silica with selected models of CD emitting centers, like surface functional groups (OH and COOH), dopants (graphitic N), and citric acid-based molecules. The combined experimental and theoretical results clearly indicate the presence of molecular species and surface centers both emitting in the blue and green spectral range, whose relative contribution is tuned by the interaction with the surrounding media.
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Affiliation(s)
- Chiara Olla
- Department of Physics, University of Cagliari, I-09042 Monserrato, Italy.
| | - Pier Carlo Ricci
- Department of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Daniele Chiriu
- Department of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Marzia Fantauzzi
- Department of Chemical and Geological Sciences, University of Cagliari, I-09042 Monserrato, Italy
| | - Maria Francesca Casula
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, I-09123 Cagliari, Italy
| | - Francesca Mocci
- Department of Chemical and Geological Sciences, University of Cagliari, I-09042 Monserrato, Italy
| | - Antonio Cappai
- Department of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Stefania Porcu
- Department of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Luigi Stagi
- Department of Chemistry and Pharmacy, Laboratory of Materials Science and Nanotechnology, University of Sassari, Via Vienna 2, I-07100 Sassari, Italy
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6
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Langer M, Zdražil L, Medveď M, Otyepka M. Communication of molecular fluorophores with other photoluminescence centres in carbon dots. NANOSCALE 2023; 15:4022-4032. [PMID: 36728225 DOI: 10.1039/d2nr05114a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The establishment of structure-photoluminescence (PL) relationships remains an ultimate challenge in the field of carbon dots (CDs). It is now commonly understood that various structural domains may evolve during the preparation of CDs; nonetheless, we are still far from capturing the specific features that determine the overall PL of CDs. Although the core, surface and molecular states are usually considered the three main sources of PL, it is not known to which extent they interact and/or affect one another. Expectedly, the communication between the different PL centres depends on the mutual arrangement and the type of linking. To gain insights into such a communication, time-dependent density functional theory (TD-DFT) calculations were performed for several (N-doped/O-functionalized) polyaromatic hydrocarbons (PAHs) as representative models for the core/surfaces PL states and the prototypical molecular fluorophore (MF) 5-oxo-1,2,3,5-tetrahydroimidazo-[1,2-α]-pyridine-7-carboxylic acid (IPCA), considering different interaction modes, namely hydrogen bonded and stacked complexes as well as covalently bonded and fused structures. Our results revealed that each of the studied arrangements in some way supported the communication between the PL centres. The deactivation pathways typically involve multiple charge and energy transfer events that can promote the formation of charge separated states and/or lead to the activation of other PL centres in CDs. Depending on the arrangement, the doping pattern and surface functionalization, both the CD core and the MF can act as an electron donor or acceptor, which could help to design CDs with desirable hole-electron surface/core characteristics.
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Affiliation(s)
- Michal Langer
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 241/27, 783 71 Olomouc, Czech Republic.
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies University of Warsaw, 2c Banacha Street, 02-097, Warszawa, Poland
| | - Lukáš Zdražil
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 241/27, 783 71 Olomouc, Czech Republic.
| | - Miroslav Medveď
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 241/27, 783 71 Olomouc, Czech Republic.
- Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, 974 01 Banská Bystrica, Slovak Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 241/27, 783 71 Olomouc, Czech Republic.
- IT4Innovations, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic
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7
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Podkolodnaya YA, Kokorina AA, Goryacheva IY. A Facile Approach to the Hydrothermal Synthesis of Silica Nanoparticle/Carbon Nanostructure Luminescent Composites. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8469. [PMID: 36499966 PMCID: PMC9737401 DOI: 10.3390/ma15238469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Luminescent carbon nanostructures (CNSs) have been intensively researched, but there is still no consensus on a fundamental understanding of their structure and properties that limits their potential applications. In this study, we developed a facile approach to the synthesis of luminescent composite SiO2 nanoparticles/CNSs by the targeted formation of a molecular fluorophore, as the significant luminescent component of CNSs, on the surface of a silica matrix during a one-stage hydrothermal synthesis. Silica nanoparticles were synthesized by reverse microemulsion and used as a matrix for luminescent composites. The as-prepared silica nanoparticles had a functional surface, a spherical shape, and a narrow size distribution of about 29 nm. One-stage hydrothermal treatment of citric acid and modified silica nanoparticles made it possible to directly form the luminescent composite. The optical properties of composites could be easily controlled by changing the hydrothermal reaction time and temperature. Thus, we successfully synthesized luminescent composites with an emission maximum of 450 nm, a quantum yield (QY) of 65 ± 4%, and an average size of ~26 nm. The synthesis of fluorophore doped composite, in contrast to CNSs, makes it possible to control the shape, size, and surface functionality of particles and allows for avoiding difficult and time-consuming fractionation steps.
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8
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Kasprzyk W, Świergosz T, Romańczyk PP, Feldmann J, Stolarczyk JK. The role of molecular fluorophores in the photoluminescence of carbon dots derived from citric acid: current state-of-the-art and future perspectives. NANOSCALE 2022; 14:14368-14384. [PMID: 36156633 DOI: 10.1039/d2nr03176k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Carbon dots (CDs), an emerging class of nanomaterials, have attracted considerable attention due to their intriguing photophysical properties. Despite their indisputable potential of utilization in many fascinating areas of research and life, some fundamental aspects concerning their structure and the origin of their photoluminescence (PL) properties still await clarification. The mechanism of PL emission of CDs is associated with their structure, which is dependent on the carbonization process. At the initial stages of CD synthesis via a bottom-up approach, molecular fluorophores are considered to dominate the optical characteristics of the resulting nanomaterials. In this review, the recent progress in the use of molecular state theory for explanation of the structure-property relationship in CDs is summarized. This review focuses exclusively on the molecular fluorophores existing in nanomaterials prepared from citric acid (CA) as one of the most frequent carbon sources reported for the bottom-up synthesis of CDs. Consequently, the most relevant transformations of CA and the history of molecular fluorophores derived from it are described, followed by an in-depth discussion on their relevance in understanding the specific photophysical properties of blue-, green-, and red-emitting CDs. Finally, the challenging issues and future perspectives of molecular state PL mechanism exploration in CDs are highlighted.
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Affiliation(s)
- Wiktor Kasprzyk
- Department of Biotechnology and Physical Chemistry, Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
| | - Tomasz Świergosz
- Department of Chemical Technology and Environmental Analysis, Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland
| | - Piotr P Romańczyk
- Department of Biotechnology and Physical Chemistry, Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
| | - Jochen Feldmann
- Chair for Photonics and Optoelectronics, Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstrasse 10, Munich, 80539, Germany
| | - Jacek K Stolarczyk
- Chair for Photonics and Optoelectronics, Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstrasse 10, Munich, 80539, Germany
- Smoluchowski Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
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9
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Mocci F, de Villiers Engelbrecht L, Olla C, Cappai A, Casula MF, Melis C, Stagi L, Laaksonen A, Carbonaro CM. Carbon Nanodots from an In Silico Perspective. Chem Rev 2022; 122:13709-13799. [PMID: 35948072 PMCID: PMC9413235 DOI: 10.1021/acs.chemrev.1c00864] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carbon nanodots (CNDs) are the latest and most shining rising stars among photoluminescent (PL) nanomaterials. These carbon-based surface-passivated nanostructures compete with other related PL materials, including traditional semiconductor quantum dots and organic dyes, with a long list of benefits and emerging applications. Advantages of CNDs include tunable inherent optical properties and high photostability, rich possibilities for surface functionalization and doping, dispersibility, low toxicity, and viable synthesis (top-down and bottom-up) from organic materials. CNDs can be applied to biomedicine including imaging and sensing, drug-delivery, photodynamic therapy, photocatalysis but also to energy harvesting in solar cells and as LEDs. More applications are reported continuously, making this already a research field of its own. Understanding of the properties of CNDs requires one to go to the levels of electrons, atoms, molecules, and nanostructures at different scales using modern molecular modeling and to correlate it tightly with experiments. This review highlights different in silico techniques and studies, from quantum chemistry to the mesoscale, with particular reference to carbon nanodots, carbonaceous nanoparticles whose structural and photophysical properties are not fully elucidated. The role of experimental investigation is also presented. Hereby, we hope to encourage the reader to investigate CNDs and to apply virtual chemistry to obtain further insights needed to customize these amazing systems for novel prospective applications.
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Affiliation(s)
- Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy,
| | | | - Chiara Olla
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Antonio Cappai
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Maria Francesca Casula
- Department
of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, IT 09123 Cagliari, Italy
| | - Claudio Melis
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Luigi Stagi
- Department
of Chemistry and Pharmacy, Laboratory of Materials Science and Nanotechnology, University of Sassari, Via Vienna 2, 07100 Sassari, Italy
| | - Aatto Laaksonen
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy,Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden,State Key
Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China,Centre
of Advanced Research in Bionanoconjugates and Biopolymers, PetruPoni Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda 41A, 700487 Iasi, Romania,Division
of Energy Science, Energy Engineering, Luleå
University of Technology, Luleå 97187, Sweden,
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10
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Harnessing Molecular Fluorophores in the Carbon Dots Matrix: The Case of Safranin O. NANOMATERIALS 2022; 12:nano12142351. [PMID: 35889575 PMCID: PMC9315549 DOI: 10.3390/nano12142351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 11/24/2022]
Abstract
The origin of fluorescence in carbon dots (C-dots) is still a puzzling phenomenon. The emission is, in most of the cases, due to molecular fluorophores formed in situ during the synthesis. The carbonization during C-dots processing does not allow, however, a fine control of the properties and makes finding the source of the fluorescence a challenging task. In this work, we present a strategy to embed a pre-formed fluorescent molecule, safranin O dye, into an amorphous carbonaceous dot obtained by citric acid carbonization. The dye is introduced in the melted solution of citric acid and after pyrolysis remains incorporated in a carbonaceous matrix to form red-emitting C-dots that are strongly resistant to photobleaching. Embedding dyes in amorphous C-dots represents an alternative method to optimize the emission in the whole visible spectrum.
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11
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Fluorescent Zn(II)-Based Metal-Organic Framework: Interaction with Organic Solvents and CO 2 and Methane Capture. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123845. [PMID: 35744975 PMCID: PMC9228242 DOI: 10.3390/molecules27123845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/27/2022] [Accepted: 06/02/2022] [Indexed: 12/03/2022]
Abstract
Adsorption of carbon dioxide (CO2), as well as many other kinds of small molecules, is of importance for industrial and sensing applications. Metal-organic framework (MOF)-based adsorbents are spotlighted for such applications. An essential for MOF adsorbent application is a simple and easy fabrication process, preferably from a cheap, sustainable, and environmentally friendly ligand. Herein, we fabricated a novel structural, thermally stable MOF with fluorescence properties, namely Zn [5-oxo-2,3-dihydro-5H-[1,3]-thiazolo [3,2-a]pyridine-3,7-dicarboxylic acid (TPDCA)] • dimethylformamide (DMF) •0.25 H2O (coded as QUF-001 MOF), in solvothermal conditions by using zinc nitrate as a source of metal ion and TPDCA as a ligand easy accessible from citric acid and cysteine. Single crystal X-ray diffraction analysis and microscopic examination revealed the two-dimensional character of the formed MOF. Upon treatment of QUF-001 with organic solvents (such as methanol, isopropanol, chloroform, dimethylformamide, tetrahydrofuran, hexane), interactions were observed and changes in fluorescence maxima as well as in the powder diffraction patterns were noticed, indicating the inclusion and intercalation of the solvents into the interlamellar space of the crystal structure of QUF-001. Furthermore, CO2 and CH4 molecule sorption properties for QUF-001 reached up to 1.6 mmol/g and 8.1 mmol/g, respectively, at 298 K and a pressure of 50 bars.
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12
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Gadly T, Chakraborty G, Tyagi M, Patro BS, Dutta B, Potnis A, Chandwadkar P, Acharya C, Suman SK, Mukherjee A, Neogy S, Wadawale A, Sahoo S, Chauhan N, Ghosh SK. Carbon nano-dot for cancer studies as dual nano-sensor for imaging intracellular temperature or pH variation. Sci Rep 2021; 11:24341. [PMID: 34934094 PMCID: PMC8692618 DOI: 10.1038/s41598-021-03686-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Cellular temperature and pH govern many cellular physiologies, especially of cancer cells. Besides, attaining higher cellular temperature plays key role in therapeutic efficacy of hyperthermia treatment of cancer. This requires bio-compatible, non-toxic and sensitive probe with dual sensing ability to detect temperature and pH variations. In this regard, fluorescence based nano-sensors for cancer studies play an important role. Therefore, a facile green synthesis of orange carbon nano-dots (CND) with high quantum yield of 90% was achieved and its application as dual nano-sensor for imaging intracellular temperature and pH was explored. CND was synthesized from readily available, bio-compatible citric acid and rhodamine 6G hydrazide using solvent-free and simple heating technique requiring purification by dialysis. Although the particle size of 19 nm (which is quite large for CND) was observed yet CND exhibits no surface defects leading to decrease in photoluminescence (PL). On the contrary, very high fluorescence was observed along with good photo-stability. Temperature and pH dependent fluorescence studies show linearity in fluorescence intensity which was replicated in breast cancer cells. In addition, molecular nature of PL of CND was established using pH dependent fluorescence study. Together, the current investigation showed synthesis of highly fluorescent orange CND, which acts as a sensitive bio-imaging probe: an optical nano-thermal or nano-pH sensor for cancer-related studies.
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Affiliation(s)
- Trilochan Gadly
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India.
| | - Goutam Chakraborty
- Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Mrityunjay Tyagi
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Birija S Patro
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Bijaideep Dutta
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Akhilesh Potnis
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Pallavi Chandwadkar
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Celin Acharya
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Shishu Kant Suman
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Archana Mukherjee
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Suman Neogy
- Material Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Amey Wadawale
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Srikant Sahoo
- Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Nitish Chauhan
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Sunil K Ghosh
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
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13
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Jana B, Reva Y, Scharl T, Strauss V, Cadranel A, Guldi DM. Carbon Nanodots for All-in-One Photocatalytic Hydrogen Generation. J Am Chem Soc 2021; 143:20122-20132. [PMID: 34843242 DOI: 10.1021/jacs.1c07049] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Carbon nanodots (CNDs) were photochemically altered to produce dihydrogen under light irradiation. Within the complex structure of CNDs, photo-oxidation takes place at citrazinic acid molecular fluorophore sites. Important is the fact that the resulting CND materials have a dual function. On one hand, they absorb light, and on the other hand, they photo- and electrocatalytically produce dihydrogen from water and seawater, without any external photosensitizer or cocatalyst. Record HER activities of 15.15 and 19.70 mmol(H2) g(catalyst)-1 h-1 were obtained after 1 h of 75 mW/cm2 Xe lamp illumination, from water and seawater, respectively. This impressive performance outweighs the remaining structural uncertainties. A full-fledged physicochemical investigation based on an arsenal of steady-state and time-resolved spectroscopic characterizations together with microscopy enabled a comprehensive look into the reaction mechanism. For an efficient dihydrogen formation, a precatalytic activation by means of reduction with a sacrificial electron donor is imperative.
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Affiliation(s)
- Bikash Jana
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Yana Reva
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Tobias Scharl
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Volker Strauss
- Max Planck Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Alejandro Cadranel
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.,Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Química Física de Materiales, Medio Ambiente y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
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14
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Das S, Ngashangva L, Goswami P. Carbon Dots: An Emerging Smart Material for Analytical Applications. MICROMACHINES 2021; 12:84. [PMID: 33467583 PMCID: PMC7829846 DOI: 10.3390/mi12010084] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 12/16/2022]
Abstract
Carbon dots (CDs) are optically active carbon-based nanomaterials. These nanomaterials can change their light emission properties in response to various external stimuli such as pH, temperature, pressure, and light. The CD's remarkable stimuli-responsive smart material properties have recently stimulated massive research interest for their exploitation to develop various sensor platforms. Herein, an effort has been made to review the major advances made on CDs, focusing mainly on its smart material attributes and linked applications. Since the CD's material properties are largely linked to their synthesis approaches, various synthesis methods, including surface passivation and functionalization of CDs and the mechanisms reported so far in their photophysical properties, are also delineated in this review. Finally, the challenges of using CDs and the scope for their further improvement as an optical signal transducer to expand their application horizon for developing analytical platforms have been discussed.
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Affiliation(s)
| | | | - Pranab Goswami
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; (S.D.); (L.N.)
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15
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Soni N, Singh S, Sharma S, Batra G, Kaushik K, Rao C, Verma NC, Mondal B, Yadav A, Nandi CK. Absorption and emission of light in red emissive carbon nanodots. Chem Sci 2021; 12:3615-3626. [PMID: 34163635 PMCID: PMC8179431 DOI: 10.1039/d0sc05879c] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The structure–function relationship, especially the origin of absorption and emission of light in carbon nanodots (CNDs), has baffled scientists. The multilevel complexity arises due to the large number of by-products synthesized during the bottom-up approach. By performing systematic purification and characterization, we reveal the presence of a molecular fluorophore, quinoxalino[2,3-b]phenazine-2,3-diamine (QXPDA), in a large amount (∼80% of the total mass) in red emissive CNDs synthesized from o-phenylenediamine (OPDA), which is one of the well-known precursor molecules used for CND synthesis. The recorded NMR and mass spectra tentatively confirm the structure of QXPDA. The close resemblance of the experimental vibronic progression and the mirror symmetry of the absorption and emission spectra with the theoretically simulated spectra confirm an extended conjugated structure of QXPDA. Interestingly, QXPDA dictates the complete emission characteristics of the CNDs; in particular, it showed a striking similarity of its excitation independent emission spectra with that of the original synthesized red emissive CND solution. On the other hand, the CND like structure with a typical size of ∼4 nm was observed under a transmission electron microscope for a blue emissive species, which showed both excitation dependent and independent emission spectra. Interestingly, Raman spectroscopic data showed the similarity between QXPDA and the dot structure thus suggesting the formation of the QXPDA aggregated core structure in CNDs. We further demonstrated the parallelism in trends of absorption and emission of light from a few other red emissive CNDs, which were synthesized using different experimental conditions. Herein we unveil the presence of a molecular fluorophore quinoxalino[2,3-b]phenazine-2,3-diamine (QXPDA) in a colossal amount in red emissive CNDs synthesized from o-phenylenediamine, a well-known precursor molecule used for CND synthesis.![]()
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Affiliation(s)
- Neeraj Soni
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Shivendra Singh
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Shubham Sharma
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Gayatri Batra
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Kush Kaushik
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Chethana Rao
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Navneet C Verma
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Bhaskar Mondal
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India
| | - Aditya Yadav
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India
| | - Chayan K Nandi
- School of Basic Sciences, Indian Institute of Technology Mandi H.P. 175075 India .,Advanced Materials Research Centre, Indian Institute of Technology Mandi H.P. 175075 India.,BioX Centre, Indian Institute of Technology Mandi H.P. 175075 India
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