Effect of the chemical nature of the nitrogen source on the physicochemical and optoelectronic properties of carbon quantum dots (CQDs)
Stephania Rosales, Karol Zapata, Oscar E. Médina, Benjamín Alberto Rojano, Esteban A. Taborda, Farid B. Cortés, Agustín F. Pérez‐Cadenas, Esther Bailón‐García, Francisco Carrasco-Marı́n, Camilo A. Franco
Abstract
-conjugated domains, promoting electron delocalization and enhancing both electronic transitions and fluorescence efficiency. However, physical properties, such as particle size and thermal stability, remained unaffected by the choice of the nitrogen precursor. The CQDs demonstrated excellent thermal stability, ionic strength resistance, and long-term fluorescence retention, maintaining up to 90% of their initial fluorescence intensity under various storage conditions, making them suitable for use in harsh environments. However, an extremely acidic pH had the most detrimental effect, causing fluorescence intensity losses of up to 80% in CQD-phenylenediamine and CQD-diethylamine. These findings highlight the important role of nitrogen in enhancing the optoelectronic properties of the CQDs. Appropriate selection of the nitrogen source can significantly improve the fluorescence performance and optimize the response for practical applications.