High quantum yield and green emission carbon quantum dots (CQDs) are synthesized by heterogeneous nucleation and growth in a solvothermal system. o-phenylenediamine (o-PD) was utilized as precursors of the N-doped CQDs, and various heteromaterials such as ZnO, TiO2, and NiO take the role of nucleation sites to control the nucleation rate of the reaction. The CQDs is characterized by UV-vis spectroscopy, fluorescence spectroscopy (FP), dynamic light scattering (DLS), transmission electron microscope (TEM), scanning electron microscope with energy dispersive X-Ray analysis (SEM-EDX), and Fourier–Transform Infrared Spectroscopy (FT-IR). The results show that the N-doped CQD prepared by heterogeneous nucleation process with titanium oxide have an emission peak at 498 nm upon excited by 420 nm excitation wavelength. The observation from TEM reveals that the size of CQDS are 11 – 15 nm. The quantum yield of these N-doped CQDs measured in ethanol solution is about 62.81% which is higher than CQDs prepared by homogeneous nucleation (17.34%). The increase in quantum yield is ascribed to the reduce of energy barrier for CQDs formation resulting more nuclei of CQDs are formed. Owing to the remarkable improvement in the optical properties, these green emission CQDs have great potential for applications that able incorporated onto polymer that formed stable polymer thin film.

1. Shamsipur, M.; Barati, A.; Karami, S.; “Long - wavelength, Multicolor, and White – light Emitting Carbon – based Dots : Achievement Made Challenges Remaining, and Applications.” Carbon, 2017, 124, 429 – 472.
2. Wang, H.; Sun, C.; Chen, X.; Zhang, Y.; Colvin, VL.; Rice, Q.; Seo, J.; Feng, S.; Wang, S.; Yu, WW.; “Excitation Wavelength Independent Visible Color Emission of Carbon Dots.” Nanoscale, 2017, 9, 1909.
3. Chu, KW.; Lee, SL.; Chang, CJ.; Liu, L.; “Recent Progress of Carbon Dots Precursors and Photocatalysis Applications.” Polymers, 2019, 11, 689.
4. Joseph, J.; Anappara, AA.; “Microwave – assisted Hydrothermal Synthesis of UV – emitting Carbon Dots from Tannic Acid.” New J. Chem., 2016, 40, 8110.
5. Zhang, T.; Zhu, J.; Zhai, Y.; Wang, H.; Bai, X.; Dong, B.; Wang, H.; Song, H.; “A Novel Mechanism for Red Emission Carbon Dots : Hydrogen Bond Dominated Molecular States Emission.” Nanoscale, 2017, 9, 13042.
6. Yuan, F.; Yuan, T.; Sui, L.; Wang, Z.; Xi, Z.; Li, Y.; Li, X.; Fan, L.; Tan, Z.; Chen, A.; Jin, M.; Yang, S.; “Engineering Triangular Carbon Quantum Dots with Unprecedented Narrow Bandwidth Emission for Multicolored LEDs.” Nature Communications, 2018, 9, 2249.
7. Jiang, K.; Sun, S.; Zhang, L.; Lu, Y.; Wu, A.; Cai, C.; Lin, H.; “Red, Green, and Blue Luminescence by Carbon Dots : Full – Color Emission Tuning and Multicolor Cellular Imaging.” Angew. Chem. Int. Ed, 2015, 54, 5360 – 5363.
8. Lin, S.; Lin, C.; He, M.; Yuan, R.; Zhang, Y.; Zhou, Y.; Xiang, W.; Liang, X.; “Solvatochromism of Bright Carbon Dots with Tunable Long – Wavelength Emission from Green to Red and Their Applications as Solid – State Materials for Warm WLEDs.” RSC Adv., 2017, 7, 41552 – 41560.
9. Li, X.; Zhang, K.; Li, J.; Chen, J.; Wu, Y.; Liu, K.; Song, J.; Zeng, H.; “Heterogeneous Nucleation toward Polar – Solvent Free, Fast, and One – Pot Synthesis of Highly Uniform Perovskite Quantum Dots for Wider Color Gamut Display.” Adv. Mater. Interfaces., 2018, 1800010.
10. Kausar, A.; “Polymer / Carbon – Based Quantum Dot Nanocomposite : Forthcoming Materials for Technical Application.” Journal of Macromolecular Science, Part A : Pure and Applied Chemistry., 2019, Vol 56 No. 4, 341 – 356.
11. Yu, H.; Lu, Y.; Feng, Z.; Wu, Y.; Liu, Z.; Xia, PF.; Qian, J.; Chen, Y.; Liu, L.; Cao, K.; Chen, S.; Huang, W.; “A MAPbBr3:Poly(ethylene oxide) Composite Perovskite Quantum Dot Emission Layer : Enhanced Film Stability, Coverage, and Device Performance, Nanoscale, 2019, Vol 11, 9103.
12. Shinde, KN.; Dhoble, SJ.: Swart, HC.; Park, K.: “Phosphate Phosphors for Solid – State Lighting.” Springer : Chapter II : Basic Mechanism of Photoluminescence., 2012.
13. Manor, A.; Kruger, N.; Rotschild.; “Entropy Driven Multi – Photon Frequency Up – Conversion.” Optical Society of America, 2013, paper Q2FD.1.
14. Kumar,D.; “Co – Functionalized Gold Nanoparticles for Drug Delivery Applications.” Thesis : University of Ulster, 2012, Faculty of Computing & Engineering.
15. Adiono, T.; Fuada, S.; Harimurti S.; “Bandwidth Budget Analysis for Visible Light Communication Systems Utilizing Commercially Available Components.” Conference : The 10th International Conference on Electrical and Electronics Engineering (ELECO 2017), 2017, Volume 10.

16. Sharma, S.; Dutta, V.; Singh, P.; Raizada, P.; Rahmani-Sani, A.; Hosseini-Bandegharaei, A.; Thakur, VJ.; “Carbon Quantum Dots Supported Semiconductor Photocatalyst for Efficient Degradation of Organic Pollutants in Water : A Review.” Journal of Cleaner Production, 2019, Vol. 228, 755 – 769.
17. Gayen, B.; Palchoudhury, S.; Chowdhury, J.; “Carbon Dots : A Mystic Star in the World of Nanoscience.” Journal of Nanomaterials, 2019, Vol. 2019, 3451307.
18. Xia, C.; Zhu, S.; Feng, T.; Yang, M.; Yang, B.; “Evolution and Synthesis of Carbon Quantum Dots : From Carbon Dots to Carbonized Polymer Dots.” Adv. Sci., 2019, 6, 1901316.
19. Wang, R.; Lu, KQ.; Tang, ZR.; Xu, YJ.; “Recent Progress in Carbon Quantum Dots : Synthesis, Properties, and Application in Photocatalysis.” J. Mater. Chem. A, 2017, 5, 3717.
20. Khare, P.; Bhati, A.; Anand, SR.; Gunture.; Sonkar, SK.; “Brightly Fluorescent Zinc – Doped Red – Emitting Carbon Dots for the Sunlight – Induced Photoreduction of Cr (VI) to CR (III).” ACS Omega, 2018, 3, 5187 – 5194.
21. Hu, S.; Trinchi, A.: Atkin, P.; Cole, I.: “Tunable Photoluminescence Across the Entire Visible Spectrum from Carbon Dots Excited by White Light.” Angew. Chen. Int. Ed, 2015, 54, 2970 – 2974.
22. Li, H.; He, X.; Kang, Z.; Huang, H.; Liu, Y.; Liu, J.; Lian, S.; Tsang, CHA.; Yang, X.; Lee, ST.: “Water – Soluble Fluorescence Carbon Quantum Dots and Photocatalyst Design.” Angew. Chem. Int. Ed, 2010, 49, 4430 – 4434.
23. Ding, H.; Yu, SB.; Wei, JS.: Xiong, HM.; “Full – Color Light – Emitting Carbon Dots with a Surface – State Controlled Luminescence Mechanism.” ACS Nano, 2016, 484 – 491.

24. Zhang, F.; Wang, S.; Wang, L.; Lin, Q.; Shen, H.; Cao, W.; Yang, C.; Wang, H.; Yu, L.; Du, Z.; Xue, J.; Li, LS.; “Super Color Purity Green Quantum Dot Light – Emitting Diodes Fabricated by Using CdSe / CdS Nanoplateletes.” Nanoscale, 2016, 8, 12182.
25. Ramasamy, P.; Kim, N.; Kang, YS.; Ramirez, O.; Lee, JS.; “Tunable, Bright, and Narrow – Band Photoluminescence from Colloidal Indium Phosphide Quantum Dots.” Chem. Mater., 2017, 29, 6893 – 6899.
26. Li, X.; Zhao, Z.; Pan, C.; “Electrochemical Oxidation of Carbon Dots with The Narrowest Full Width Half Maximum in Their Fluorescence Spectra in The Ultraviolet Region Using Only Water as Electrolyte.” Chem. Commun., 2016, 52, 9406.
27. He, P.; Shi, Y.: Meng, T.; Yuan, T.; Li, Y.: Li, X.; Zhang, Y.; Fan, L.; Yang, S.: “Recent Advances in White Light – Emitting Diodes of Carbon Quantum Dots.” Nanoscale, 2020, 12, 4826.
28. Horiba.; “A Guide to Recording Fluorescence Quantum Yields.” Horiba UK Limited.
29. Brouwer, AM.; “Standards for Photoluminescence Quantum Yield Measurements in Solution (IUPAC Technical Report).” Pure Appl. Chem, 2011, Vol. 83, 12, 2213 – 2228.
30. Huang, H.; Li, H.; Wang, AJ.; Zhong, SX.; Fang, KM.; Feng, JJ.; “Green Synthesis of Peptide – Templated Fluorescent Copper Nanoclusters for Temperature Sensing and Cellular Imaging.” Analyst, 2014, 139, 6536.
31. Molaei, JM.; “Principles, Mechanism, and Application of Carbon Quantum Dots in Sensors : A Review.” Anal. Methods, 2020, 12, 1266.
32. Wang, R.; Lu, KQ.; Tang, ZR.; Xu, YJ.; “Recent Report Progress in Carbon Quantum Dots : Synthesis, Properties, and Applications in Photocatalysis.” J. Mater. Chem. A, 2017, 5, 3717.
33. Sharma, S.; Dutta, V.; Singh, P.; Raizada, P.; Ahmani, RS.; Ahmad, HB.; Thakur, KT.; “Carbon Quantum Dots Supported Semiconductor Photocatalyst for Efficient Degradation of Organic Pollutants in Water : A Review.” Journal of Cleaner Production, 2019, 228, 755 – 769.
34. Lim, SY.; Shen, W.; Gao, Z.; “Carbon Quantum Dots and Their Applications.” Chem. Soc. Rev., 2015, 44, 362.
35. Wang, X.; Feng, Y.; Dong, P.; Huang, J.; “A Mini Review on Carbon Quantum Dots : Preparation, Properties, and Electrocatalytic Application.” Front. Chem., 2019, 7 : 671.
36. He, P.; Shi, Y.; Meng, T.; Yuan, T.; Li, Y.; Li, X.; Zhang, Y.; Fan, L.; Yang, S.; “Recent Advances in White Light – Emitting Diodes of Carbon Quantum Dots.” Nanoscale, 2020, 12, 4826.
37. Yuan, T.; Meng, T.; He, P.; Shi, YX.; Li, Y.; Li, X.; Fan, L. Yang, S.; “Carbon Quantum Dots : An Emerging Material for Optoelectronic Applications.” J. Mater. Chem. C, 2019, 7, 6820.
38. Gao, X.; Du, C.; Zhuang, Z.; Chen, W.; “Carbon Quantum Dot – Based Nanoparticles for Metal Ion Detection.” J. Mater. Chem. C, 2016, 4, 6927.
39. Kudera, S.; Zhang, Q.; Pelaz, B.; Parak, WJ.; “Inorganic Core – Shell Nanoparticles.” Elsevier, 2011.
40. Li, X.; Zhang, K.; Li, J.; Chen, J.; Wu, Y.; Liu, K.; Song, J.; Zeng, H.; “Heterogeneous Nucleation toward Polar – Solvent Free, Fast, and One – Pot Synthesis of Highly Uniform Perovskite Quantum Dots for Wider Color Gamut Display.” Adv. Mater. Interfaces, 2018, 1800010.
41. Dunne, P.; Munn, A.; Starkey, C.; Huddle, T.; Lester, E.; ”Continuous – Flow Hydrothermal Synthesis for The Production of Inorganic Nanomaterials.” Phil. Trans. R. Soc. A, 2015, 373, 20150015.
42. Shimpi, JR.; Sidhaye, DS.; Bhagavatula, LVP.; “Digestive Ripening : A Fine Chemical Maching Process on The Nanoscale.” Langmuir, 2017, 33, 9491 – 9507.
43. Kohli, R.; Mittal, KL.: “Developments in Surface Contamination and Cleaning.” Volume 6, ISBN : 9780815515555
44. Kiwi.; Rachel.” “Rotary Evaporation.” Chemoteplex and ChemJabber, 2019.
45. So, PT.; Dong, CY.; “Fluorescence Spectroscopy.” e.LS, 2001.
46. Anonim.; “Fluorescence Spectroscopy.” Horiba, 2020.
47. Stetefeld, J.; McKenna, SA.; Patel, TR.; “Dynamic Light Scattering : A Practical Guide and Applications in Biomedical Sciences.” Biophys Rev, 2016, 8(4), 409 – 427.
48. Mohrig.; “Laboratory Technique in Organic Chemistry.” 1st edition, pp 151 – 162.
49. Aryal, S. “Column Chromatography.” Microbenotes.com, 2017.
50. Teng, CY.; Nguyen, BS.; Yeh, TF.; Lee, YL.; Chen, SJ.; Teng, H.; “Roles of Nitrogen Functionalities in Enhancing the Excitation – Independent Green – Color Photoluminescence of Graphene Oxide Dots.” Nanoscale, 2017, 9, 8526.
51. Jamali, AA.; Tavakoli, A.; Dolatabadi, JEN.; “Analytical Overview of DNA Interaction with Morin and Its Metal Complexes.” Eur Food Res Technol, 2012, 235:367-373.
52. Abramowitz, M.; Davidson, MW.; “Overview of Fluorescence Excitation and Emission Fundamentals.” Olympus America Inc, 2021.