Fabrication of Ion Sensor Arrays and LEDs Using Carbon Dots From Single Synthesis and Their Formation Pathway Investigation Applying Synchronous Fluorescence Spectroscopy

ABSTRACT Carbon dots (CDs) exhibit diverse application potential in various fields due to their unique optical properties. However, CDs synthesized by conventional methods typically have complex compositions and lack efficient separation and purification techniques, limiting their performance in specific applications. In this work, we synthesized CDs via a solvothermal method and, for the first time, employed synchronous fluorescence spectroscopy (SFS) to determine the relative content of each CD type during synthesis. By leveraging SFS's high selectivity and resistance to spectral overlap, we analyzed the mixture's composition, successfully identifying blue fluorescent CDs (B‐CDs), green fluorescent CDs (G‐CDs), and orange fluorescent CDs (O‐CDs). The optimal synthesis conditions for G‐CDs were 180°C for 5 h. A sensor array was constructed using the obtained CDs as sensing elements for distinguishing and recognizing metal ions, and the sensor array has shown good recognition and discrimination ability for various metal ions. G‐CDs and O‐CDs were mixed with polyvinylpyrrolidone (PVP) to prepare CDs/PVP composite materials, demonstrating their potential in light emitting diode (LED) applications. SFS simplifies the synthesis and purification of CDs, providing key guidance for controlled CD synthesis, increased yield, and optimized fluorescence.