Electrochemical Tuning of Luminescent Carbon Nanodots: From Preparation to Luminescence Mechanism

Abstract

The size of C-nanodots can be electrochemically tuned by changing the applied potential during their preparation. The higher the applied potential, the smaller the resulting C-nanodots. Moreover, the surface oxidation degree of the C-nanodots can also be electrochemically tuned. The red-shift of emission independent of the size provides an insight into the luminescence mechanism of C-nanodots.

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

“…Their photoluminescence characteristics are linked to the sizes and ratio of sp 2 and sp 3 domains. The mechanism is considered complex and involves 1) defects' state emission/surface energy traps and 2) intrinsic state emissions, which include electron–hole recombination, quantum size effects/zigzag states 170, 171, 172, 173, 174. The emission characteristics were linked to surface chemistry and thus to alterations in the bandgap 175.…”

Scale‐Up Synthesis of Fragrant Nitrogen‐Doped Carbon Dots from Bee Pollens for Bioimaging and Catalysis

“…In vivid contrast, the yellow turbid suspension of bee pollen changes to brown transparent solution of CDs after purification, as shown in Figure 1c. Like many other CDs,[[qv: 2a]],[[qv: 4a]],[[qv: 5e]],10 the fluorescence emission of the r‐CDs is excitation wavelength dependent, tunable from 425 to 505 nm upon excitation from 340 to 450 nm, enabling the observation of visible color shift from blue through cyan to green (Figure 1 b,d). The fluorescence QY upon excitation at 380 nm was calculated to be 9.1%, using quinine sulfate as the reference.…”

Dual‐Color‐Emitting Carbon Nanodots for Multicolor Bioimaging and Optogenetic Control of Ion Channels

“…It has been known that the optical property of CNDs largely depends upon their surface states, or more specifically, their functional groups, the defect density, and the presence of adsorbates on the surface of CNDs 5. Accordingly, in the past decade, many research efforts have been devoted for modifying and controlling the surface characteristics of CNDs to expand their applicability 6, 7, 8, 9, 10. In this context, for instance, the photoluminescence (PL) wavelength could be controlled via the energy‐level engineering,6, 7 the ion selectivity could be endowed for detecting metal ions,8 and the biocompatibility could be improved for biomedical applications 9, 10, 11.…”

“…Accordingly, in the past decade, many research efforts have been devoted for modifying and controlling the surface characteristics of CNDs to expand their applicability 6, 7, 8, 9, 10. In this context, for instance, the photoluminescence (PL) wavelength could be controlled via the energy‐level engineering,6, 7 the ion selectivity could be endowed for detecting metal ions,8 and the biocompatibility could be improved for biomedical applications 9, 10, 11. On the basis of these unique characteristics,12, 13 CNDs have been exploited for a variety of biomedical applications, such as diagnostic applications,14 photoacoustic imaging, and the photothermal therapy 15, 16, 17…”