Pressure-triggered aggregation-induced emission enhancement in red emissive amorphous carbon dots

Carbon dots have received extensive attention due to their unique chemical structure, excellent optoelectronic properties and convenient synthesis. However, the synthesis of carbon dots with stable red wavelength luminescence remains a challenge. Here, we used the ethanol solvothermal method with 1,3,5-benzenetrithiol as the raw material to prepare carbon dots with red emission (R-CDs). When the concentration of R-CDs increased, the fluorescence emission of the R-CDs red-shifted to the near infrared region. Importantly, the as-synthesized R-CDs offer fluorescence enhancement under external pressure due to pressure-triggered aggregation-induced emission. Fluorescence measurements of the depressurization process show that the R-CDs also have a reversible piezochromic luminescence (1 atm-1.2 GPa). The R-CDs have notable optical properties and great biocompatibility, and we used them for a transparent fluorescent thin film, light emitting diode (LED) and cell imaging. The excellent optical properties of R-CDs indicate their broad potential applicability in biomedical and luminescent materials.