Tuning photoluminescence and surface properties of carbon nanodots for chemical sensing

Abstract

Obtaining tunable photoluminescence (PL) with improved emission properties is crucial for successfully implementing fluorescent carbon nanodots (fCDs) in all practical applications such as multicolour imaging and multiplexed detection by a single excitation wavelength. In this study, we report a facile hydrothermal approach to adjust the PL peaks of fCDs from blue, green to orange by controlling the surface passivation reaction during the synthesis. This is achieved by tuning the passivating reagents in a step-by-step manner. The as-prepared fCDs with narrow size distribution show improved PL properties with different emission wavelengths. Detailed characterization of fCDs using elemental analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy suggested that the surface chemical composition results in this tunable PL emission. Surface passivation significantly alters the surface status, resulting in fCDs with either stronger surface oxidation or N element doping that ultimately determine their PL properties. Further experiments suggested that the as-prepared orange luminescent fCDs (O-fCDs) were sensitive and specific nanosensing platforms towards Fe(3+) determination in a complex biological environment, emphasizing their potential practical applications in clinical and biological fields.

Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

“…Zhang et al. reported the synthesis of the green, blue, and orange emission of CDs through the sequential passivation with PEG1000 and 2,2′‐(ethylenedioxy)bis(ethylamine), which resulted from the different oxygen states and N configurations (Figure b) . As shown in the above examples, surface passivation plays an important role in controlling the surface state of CDs without altering the core states of the CDs.…”

Highly Sensitive Detection of Fe3+ Ions Using Waterborne Polyurethane‐Carbon Dots Self‐Healable Fluorescence Film

“…The F 0 /F‐1 ratio had an obviously very relating linear ( R 2 = 0.9976) with the Fe 3+ concentration in the range from 0 to 200 × 10 −6 m in Figure 7c, compared with the previously reported values, it was much larger. [ 41,42 ] Herein, F and F 0 were the fluorescence intensities of the WBPU‐3 film at 420 nm in the presence and absence of Fe 3+ ions, respectively. The limit of detection (LOD) was evaluated to be 2.19 × 10 −6 m at a signal‐to‐noise ratio of 3.…”

Advanced Near‐Infrared Light‐Responsive Nanomaterials as Therapeutic Platforms for Cancer Therapy

“…[134] Hence, surface modification is another route to achieve multicolor and long wavelength emissions in CDs. [144] In their report, PEG 400 was first heated up in a round-bottom flask at 150°C for 12 h until a faint yellow solution was formed. [143] Detailed studies were carried out to investigate the surface states and it was found that surface moieties such as C═O and C═N were found on multicolor CDs, which could introduce a lot of structural configurations and new energy levels, resulting in many electronic transition possibilities.…”