Interparticle distance as a key factor for controlling the dual-emission properties of carbon dots

Abstract

<p>The dominant emission color of multi-color emissive carbon dots under a single excitation source is governed by the interparticle distance.</p>

Pressure-Induced Bifurcation in the Photoluminescence of Red Carbon Quantum Dots: Coexistence of Emissions from Surface Groups and Nitrogen-Doped Cores

“…The XPS full spectrum of R-CDs exhibits three peaks at 285.0, 400.0, and 532.0 eV in Figure c, which are attributed to C 1s, N 1s, and O 1s, respectively. The C:N:O atom ratio determined from the fitting to the XPS full spectrum is 63.5:16.8:19.7, suggesting substantial N- and O-related groups. − As shown in panels d–f of Figure , the fittings to the high-resolution C 1s, N 1s, and O 1s spectra, respectively, clarify the chemical bonds in R-CDs. The COO – bond in the C 1s spectrum at 288.5 eV of Figure d is in the region that is typical for carboxylic groups, while the unequal C–O and CO bands in the O 1s spectrum of Figure f suggest that carbonyl (CO) and/or hydroxyl (C–O–H) groups are also likely present at the surface.…”

“…The strong absorption band at 1650 cm –1 may be attributed to aromatic CC or CO stretching vibrations. The broad absorption at approximately 3070–3260 cm –1 corresponds to the N–H stretching vibration, indicating the presence of the primary amine, and the broad absorption at approximately 3280–3660 cm –1 arises from -OH groups. , To further determine the chemical structure and groups in R-CDs, X-ray photoelectron spectroscopy (XPS) of the sample was performed. The XPS full spectrum of R-CDs exhibits three peaks at 285.0, 400.0, and 532.0 eV in Figure c, which are attributed to C 1s, N 1s, and O 1s, respectively.…”

Interfacing Carbon Dots for Charge‐Transfer Processes

“…Surface-passivation mechanisms also take place during the bottom-up synthesis, furnishing CDs with desired functionalities on the surface of their core-shell structure. Moreover, complementary interactions, that is, hydrogen bonds, [35] solvation, [36] and inter-particle distance, [37] may further improve or tune their photoluminescence properties and enhance the fluorescence quantum yields enabling full exploitation of their photoinduced redox characteristics. [38] Pristine and functionalized CDs have been reported to participate in several charge-transfer schemes, likewise photocatalysis (i.e., solar-to-hydrogen conversion, water splitting, CO 2 conversion, degradation of organics, organic transformations), [39] electrocatalysis (i.e., water splitting, hydrogen evolution, CO 2 reduction), [39c,d] electrochemical sensing, [39c,d] lithium-ion batteries (as cathode, anodes or electrolyte materials), [39d,40] sup ercapacitors, [39d,41] light-emitting diodes, [42] solar cells [39d,43] and turn-on/turn-off biosensors.…”

Application of high-efficiency green fluorescent carbon dots prepared by acid catalysis in multicolour LEDs

“…4 Concentration-dependent wide spectral range response Surprisingly, in addition to the uorescence redshi and the QY improvements, acid-catalysed CDs exhibit a concentrationdependent redshi in the uorescence. 31 As shown in Fig. 6a, a series of CDs with different concentrations were prepared in ethanol (c ¼ 0.1, 1.0, 2.0, 5.0, 10.0, 20.0 mg mL À1 ) for direct observation.…”