Bulbous gold–carbon nanodot hybrid nanoclusters for cancer therapy

Hasenöhrl, Dominik H.; Saha, Avishek; Strauß, Volker; Wibmer, Leonie; Klein, Stefanie; Guldi, Dirk M.; Hirsch, Andreas

doi:10.1039/c7tb02039b

Cited by 14 publications

(9 citation statements)

References 48 publications

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“…pCNDs act as both reducing and stabilizing agents in Au@pCND . In the resulting bulbous metallic nanoparticles, an amorphous carbon shell capped the gold core, as revealed by TEM.…”

Section: Introductionmentioning

confidence: 93%

Carbon Nanodots for Charge-Transfer Processes

et al. 2019

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In recent years, carbon nanodots (CNDs) have emerged as an environmentally friendly, biocompatible, and inexpensive class of material, whose features sparked interest for a wide range of applications. Most notable is their photoactivity, as exemplified by their strong luminescence. Consequently, CNDs are currently being investigated as active components in photocatalysis, sensing, and optoelectronics. Chargetransfer interactions are common to all these areas. It is therefore essential to be able to fine-tune both the electronic structure of CNDs and the electronic communication in CND-based functional materials. The complex, but not completely deciphered, structure of CNDs necessitates, however, a multifaceted strategy to investigate their fundamental electronic structure and to establish structure−property relationships. Such investigations require a combination of spectroscopic methods, such as ultrafast transient absorption and fluorescence up-conversion techniques, electrochemistry, and modeling of CNDs, both in the absence and presence of other photoactive materials. Only a sound understanding of the dynamics of charge transfer, charge shift, charge transport, etc., with and without light makes much-needed improvements in, for example, photocatalytic processes, in which CNDs are used as either photosensitizers or catalytic centers, possible. This Account addresses the structural, photophysical, and electrochemical properties of CNDs, in general, and the chargetransfer chemistry of CNDs, in particular. Pressure-synthesized CNDs (pCNDs), for which citric acid and urea are used as inexpensive and biobased precursor materials, lie at the center of attention. A simple microwave-assisted thermolytic reaction, performed in sealed vessels, yields pCNDs with a fairly homogeneous size distribution of ∼1−2 nm. The narrow and excitationindependent photoluminescence of pCNDs contrasts with that seen in CNDs synthesized by other techniques, making pCNDs optimal for in-depth physicochemical analyses. The atomistic and electronic structures of CNDs were also analyzed by quantum chemical modeling approaches that led to a range of possible structures, ranging from heavily functionalized, graphene-like structures to disordered amorphous particles containing small sp 2 domains. Both the electron-accepting and -donating performances of CNDs make the charge-transfer chemistry of CNDs rather versatile. Both covalent and noncovalent synthetic approaches have been explored, resulting in architectures of various sizes. CNDs, for example, have been combined with molecular materials ranging from electron-donating porphyrins and extended tetrathiafulvalenes to electron-accepting perylendiimides, or nanocarbon materials such as polymer-wrapped single-walled carbon nanotubes. In every case, charge-separated states formed as part of the reaction cascades initiated by photoexcitation. Charge-transfer assemblies including CNDs have also played a role in technological applications: for example, a proof-ofconcept dye-sensitized solar cell was ...

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“…pCNDs act as both reducing and stabilizing agents in Au@pCND . In the resulting bulbous metallic nanoparticles, an amorphous carbon shell capped the gold core, as revealed by TEM.…”

Section: Introductionmentioning

confidence: 93%

Carbon Nanodots for Charge-Transfer Processes

et al. 2019

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“…Combining CDs with other materials in solar cells or photocatalytic devices changes the efficiency of the device, increasing or decreasing it. Some authors used femtosecond spectroscopy to investigate the optical response of these devices [109,155,213], or of the component materials used in them [216][217][218][219]. It is worth reporting here the comparison between two extreme situations.…”

Section: Ultrafast Spectroscopy On Carbon Nanodotsmentioning

confidence: 99%

Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response

2018

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Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunable fluorescence, a marked sensitivity to the environment and a range of interesting photochemical properties. CDs are currently the subject of very intense research, motivated by their possible applications in many fields, including bioimaging, solar energy harvesting, nanosensing, light-emitting devices and photocatalyis. This review covers the latest advancements in the field of CDs, with a focus on the fundamental understanding of their key photophysical behaviour, which is still very debated. The photoluminescence mechanism, the origin of their peculiar fluorescence tunability, and their photo-chemical interactions with coupled systems are discussed in light of the latest developments in the field, such as the most recent results obtained by femtosecond time-resolved experiments, which have led to important steps forward in the fundamental understanding of CDs. The optical response of CDs appears to stem from a very complex interplay between the electronic states related to the core structure and those introduced by surface functionalization. In addition, the structure of CD energy levels and the electronic dynamics triggered by photo-excitation finely depend on the microscopic structure of any specific sub-type of CD. On the other hand, this remarkable variability makes CDs extremely versatile, a key benefit in view of their very wide range of applications.

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“…Small organic molecules are common starting materials for hydrothermal or pyrolysis reactions, bringing forth new compounds and materials with intriguing properties which are valuable for a wide range of applications. [1][2][3][4][5][6][7] In particular, the socalled "carbon nanodots (CNDs)" have emerged as an interesting new class of photo-and electroactive materials and have been studied as components in functional systems and devices such as uorescent sensors, 8,9 light emitting diodes, 10 drug delivery systems, 11,12 charge storage systems, 13 photosensitizers 9,14 etc. However, there has been a consensus among experts in the eld that their structural identication and the correlation between their structure and optical properties are the most critical open questions that need to be answered.…”

Section: Introductionmentioning

confidence: 99%