Effect of Hydrothermal Reaction Temperature on Fluorescent Properties of Carbon Quantum Dots Synthesized from Lemon Juice for Adsorption Applications

Abstract

Photoluminescent carbon quantum dots (CQDs) were synthesized from lemon juice precursors via single-step, hydrothermal techniques under different temperatures to control the optical properties. The synthesized CQDs were characterized by PL, illuminated UV analyzer chamber, UV–vis spectroscopy, X-ray diffractometer, Fourier-transformed infrared spectrophotometry, and zeta potential techniques. The results show that the synthesized CQDs had an excellent blue–green emission extending up to the infrared region with high quantum yield (Φ) in the range of 14%–41%. The effect of reaction temperature and the aging of CQDs on the emission spectra of CQDs are also investigated. Furthermore, the adsorption effect of the synthesized CQDs was evaluated on methylene blue (MB) dyes. The result indicated the synthesized CQDs have excellent adsorbent properties with a removal efficiency of 60%–82% and an extremely fast adsorption rate of 6 × 10−2 min−1 for MB dyes.

High Quantum Yield Amino Acid Carbon Quantum Dots with Unparalleled Refractive Index

“…54 Additionally, this indicates that the degree of dehydration and carbonization during the formation of AA-CQDs by hydrothermal reaction may contribute to their high fluorescence and high RI. 22,55 This may be due to the reaction temperature and relatively high pressure, which aid in dehydration and carbonization and the conversion of pyridine nitrogen into pyrrole nitrogen. According to Figure 3d, the two peaks at 531.6 and 533.1 eV in the O 1s high-resolution spectrum represented C−O and C�O, respectively.…”

Biomass Derived Biofluorescent Carbon Dots for Energy Applications: Current Progress and Prospects

“…Overheating can cause C-dots to grow or degrade uncontrollably, which lowers fluorescence efficiency. [128] The surface functionalities of C-dots are influenced by temperature and can have an impact on the fluorescence properties of the dots. Increased temperature may cause some functional groups to disappear, which would affect emission behaviour.…”

“…Longer reaction periods often encourage full carbonization, which results in larger C-dots but may also lead to higher fluorescence intensity because of more fluorescent moieties being formed. [128] On the other hand, prolonged exposure periods may cause over carbonization and decreased fluorescence. The key to creating C-dots with the correct size, shape, and fluorescence properties is figuring out the best power and reaction time ratio.…”

“…There is a range of temperatures that maximize quantum yield. Overheating can cause C‐dots to grow or degrade uncontrollably, which lowers fluorescence efficiency [128] . The surface functionalities of C‐dots are influenced by temperature and can have an impact on the fluorescence properties of the dots.…”

Preparation of carbon quantum dot fluorescent probe from waste fruit peel and its use for the detection of dopamine

“…9 The methods for synthesizing CQDs include top-down and bottom-up approaches, such as hydrothermal, microwave, and electrochemical methods. 10 Gopi Kalaiyarasan et al synthesized phosphorus-doped uorescent carbon quantum dots (P-CQDs) using trisodium citrate and phosphoric acid via a hydrothermal method for the detection of iron. The uorescence quantum yield was determined to be 16.1%, and the lower limit of detection was determined to be 9.5 nmol L −1 .…”