Abstract
The nature of carbon quantum dot (CD) luminescence is still broadly investigated based on different CD synthesis processes. This study aims at investigating the effect of microwave power on optical characteristics of CDs using microwave radiation techniques. CDs are synthesized with citric acid as a source of carbon and urea as a passivation agent. CDs have been successfully synthesized, and an increase in the CD burn-off percentage was observed with an increase in the microwave power. The TEM test results show that the dimensions of the CDs resulted are in the range of 3.4–9.5 nm with an average size of 6 nm at 450 W. The results of the FTIR functional group structural analysis show that a CD has N—H and O—H stretching bonds. According to the results of UV–Vis analysis, the CDs have absorption peaks at 335 nm and 407 nm, which indicates a π → π* electronic transition from the C=C bond and an n → π* transition from the C=O bond. Using the Tauc-plot method, the CD energy bandgap values were found to be 2.47 eV, 2.51 eV, 2.51 eV, 2.52 eV, and 2.53 eV at CD 300, CD 450, CD 600, CD 850, and CD 1000, respectively. The optical multichannel analyzer test results show that the peak emission waves produced by CDs are 536 nm and 532 nm with the strongest bright green light at CD 1000. Time-resolved photoluminescence testing shows that the CD decay time generally ranges from 5 ns. Overall, an increase in the microwave power causes an increase in the percentage of burn-off, energy bandgap, absorption intensity, and CD emission intensity.
Highlights
A carbon dot (CD) is a new zero dimension carbon less than 10 nm in size.1 CDs have special characteristics, such as biocompatibility,2 easy dissolution in water,3 non-toxicity,4 chemical inertness,5 and color luminescence.6 One of the interesting aspects of CD is its optical characteristics, such as absorption and emission.CDs can emit several colors with different wavelengths depending on the size of the energy bandgap7 and is referred to as luminescence.8 The nature of luminescence is influenced by several factors that occur during and after a synthesis process
It was explained previously that the fluorescence mechanism is related to the quantum effects that arise from different sizes of nanoparticles,14 which makes the study of optical characteristics of CDs still interesting
This research aims at synthesizing CDs using the microwave irradiation technique and exploring the effect of the microwave oven power on the CD optical characteristics
Summary
A carbon dot (CD) is a new zero dimension carbon less than 10 nm in size. CDs have special characteristics, such as biocompatibility, easy dissolution in water, non-toxicity, chemical inertness, and color luminescence. One of the interesting aspects of CD is its optical characteristics, such as absorption and emission. CDs can emit several colors with different wavelengths depending on the size of the energy bandgap and is referred to as luminescence.. It was explained previously that the fluorescence mechanism is related to the quantum effects that arise from different sizes of nanoparticles, which makes the study of optical characteristics of CDs still interesting. The microwave irradiation technique offers a simple, fast, convenient, easy, and efficient synthesis process.. The microwave irradiation technique offers a simple, fast, convenient, easy, and efficient synthesis process.23 This technique has a short reaction process and can improve the quality and the purity of CDs.. This research aims at synthesizing CDs using the microwave irradiation technique and exploring the effect of the microwave oven power on the CD optical characteristics This technique has a short reaction process and can improve the quality and the purity of CDs. this research aims at synthesizing CDs using the microwave irradiation technique and exploring the effect of the microwave oven power on the CD optical characteristics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
