Síntese de derivados de dansila como precursores de Carbon Dots : aplicações como sensores de pH e diodos emissores de luz branca

Abstract

Carbon Dots (C-dots) are fluorescent carbon nanoparticles with interesting properties such as high luminescence, chemically inert, low cost, abundance of raw material, excellent biocompatibility and their diverse applications as luminescent probes and sensors, fluorescent polymers, antioxidant agents, etc. Being discovered by several precursors that influence its characteristics, dansyl chloride, having different atoms in its structures, such as S, N, O and Cl, has potential for application in the synthesis of C-dots. Therefore, the results of dansylated o, m and p-phenyldiamine, o-aminothiophenyldansylated and hydroquinonadansylated were synthesized in excellent yields (> 60%) based on evidence of nucleophilic acrylic substitutions between dansyl chloride and o, m and p-phenyldiamine, o-aminothiophenol and hydroquinone. After characterization by 1H NMR, 13C NMR and FTIR, the results and their precursors were applied to the synthesis of C-dots in hydrothermal occurrence by bottom-up rotation. The C dots exhibited specific groups of precursor materials, with N and S doping, diameters less than 6 nm, emission dependent and independent of the excitation wavelength. The C-dots obtained were incorporated into PVA films and used to assemble white LEDs using the RGB system as an external layer, and exhibited CRI of up to 92, CIE color coordinates close to pure white(0.33, 0.33) under UV and CCT protection of cold to warm WLEDs. The C-dots were evaluated against different pH values, in which the C-mPD, C-oPD and C-oPDDS demonstrated potential to be applied as pH sensors in aqueous media, since they compared pH values very similar to those found by the pH meter for real samples of distilled and mineral water.