One‐Step Fabrication of Carbon Dot‐Based Nanocomposites Powering Solid‐State Random Lasing

Abstract

Carbon dots (CDs) have attracted much attention for applications in photonics and optoelectronics because of their high emission efficiency and ease of synthesis. Although studies in solution are well established, solid‐state applications are less common because of optical quenching phenomena that critically affect CDs. Herein, the synthesis of amorphous CDs from citric acid, operating as hosts of dye molecules, and their incorporation into organic–inorganic silica matrices through a fast photo‐induced polymerization process are reported. The photocurable sol composition allows easy dispersion of nanometer‐sized scattering centers, such as titania or gold nanoparticles (NPs), which have been incorporated, along with CDs, into nanocomposites. The combination of high‐brightness CDs and nanoscatterers in the hybrid matrices allows for achieving and investigating the random lasing processes occurring in the orange‐red range of the visible spectrum. In situ‐grown gold NPs contribute to a significant improvement in solid‐state lasing, enabling an emission as narrow as 5 nm and a laser threshold as low as 0.3 mJ pulse−1. The present approach reveals the technological and scientific potential of CDs when embedded in solid‐state disordered active media.