Snapshots into carbon dots formation through a combined spectroscopic approach

Rigodanza, Francesco; Burian, Max; Arcudi, Francesca; Đorđević, Luka; Amenitsch, Heinz; Prato, Maurizio

doi:10.1038/s41467-021-22902-w

Cited by 117 publications

(78 citation statements)

References 55 publications

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“…From the analysis of morphology, it can be inferred that: at 150 °C precursor aggregates/cross-linked precursors are formed with a broad size distribution; at 200 °C alongside with those aggregates, carbonized particles with a high degree of oxidation are formed; and at 250 °C, homogeneous O-doped carbon nanoparticles are formed. These findings are similar to those observed for CD formation during microwave-assisted pyrolysis at 240 °C [ 63 ], where the particles undergo several structural configurations, starting from (i) aggregation of organic molecules, (ii) core and shell formation, (iii) shell collapse, and (iv) formation of aromatic groups within the core. It is worth mentioning that in contrast to IR1061 and other NIR emissive dyes [ 64 ] which are soluble only in non-polar solvents, NIR-CDs synthesized here are soluble in polar solvents such as acetone and water, due to their carboxylic derivative groups.…”

Section: Resultssupporting

confidence: 85%

Carbon Dots with an Emission in the Near Infrared Produced from Organic Dyes in Porous Silica Microsphere Templates

et al. 2022

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Carbon dots (CDs) with an emission in the near infrared spectral region are attractive due to their promising applications in bio-related areas, while their fabrication still remains a challenging task. Herein, we developed a template-assisted method using porous silica microspheres for the formation of CDs with optical transitions in the near infrared. Two organic dyes, Rhodamine 6G and IR1061 with emission in the yellow and near infrared spectral regions, respectively, were used as precursors for CDs. Correlation of morphology and chemical composition with optical properties of obtained CDs revealed the origin of their emission, which is related to the CDs’ core optical transitions and dye-derivatives within CDs. By varying annealing temperature, different kinds of optical centers as derivatives of organic dyes are formed in the microsphere’s pores. The template-assisted method allows us to synthesize CDs with an emission peaked at 1085 nm and photoluminescence quantum yield of 0.2%, which is the highest value reported so far for CDs emitting at wavelengths longer than 1050 nm.

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Section: Resultssupporting

confidence: 85%

Carbon Dots with an Emission in the Near Infrared Produced from Organic Dyes in Porous Silica Microsphere Templates

et al. 2022

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“…However sharp peaks at 18.6°, 19.9° and 21.4° also point towards some crystalline structure present in CND (Fig. S12 B) 31 . The zeta potential of CND in ethanol was + 1.2 mV indicating positive surface potential of CND.…”

Section: Resultsmentioning

confidence: 87%

Carbon nano-dot for cancer studies as dual nano-sensor for imaging intracellular temperature or pH variation

Gadly

Chakraborty

Tyagi

et al. 2021

Sci Rep

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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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“…Among the conventionally used basic characterization, absorption characteristics are analyzed for the identification of the electronic transition bands with the help of UV-visible absorbance spectroscopy ( Papaioannou et al., 2018 ). The PL emission and excitation spectra are measured using a fluorescence spectrometer and are the basic parameters needed for the optical sensing in carbon-based nanomaterials ( Papaioannou et al., 2018 ; Rigodanza et al., 2021 ). The absolute/relative quantum yield is measured using integrating sphere/comparing the fluorescence intensity with another sample (generally a dye) with known quantum yield ( Würth et al., 2013 ).…”

Section: Characterizationmentioning

confidence: 99%