Boron Nitride-Supported Fluorescein Isothiocyanate for Improving Optical Performance and Stability

Graphical Non-rare earth MBNNSs/FITC composite phosphor with high-intensity fluorescence emission was obtained via the incorporation of FITC into MBNNSs. The enhancement of the emission intensity of FITC in the composite phosphor can be attributed to the reduced dye aggregation via the confinement of FITC within MBNNSs, as well as the efficient energy transfer from MBNNSs host to FITC dyes. In addition, the MBNNSs/FITC composite phosphor exhibits excellent thermal and photo stabilities. Organic luminogens play an indispensable role in optoelectronic devices, yet there is a pressing need to address their aggregation-caused quenching (ACQ) and stability. Here we designed and prepared multilayered boron nitride nanosheets/fluorescein isothiocyanate (MBNNSs/FITC) composite phosphors with tunable photoluminescence by controlling the FITC content and annealing temperature. The research results indicate that MBNNSs/FITC with low or high loading of FITC is not conducive to enhancing the emission intensity of FITC, which can be attributed to the fact that low loading leads to a decrease in the content of fluorescent groups, while high loading promotes intermolecular aggregation of FITC dyes. Interestingly, the emission intensity of FITC in MBNNSs/FITC-6 composite phosphors can be further enhanced by annealing treatment (200 °C), which can be ascribed to the suppression of the ACQ and effective energy transfer from the MBNNSs to the FITC. Moreover, the resultant composite phosphor displays outstanding thermal stability, remarkable photo stability and exceptional water-resistance. This work provides a new design space for the development of non-rare-earth fluorescent materials using organic fluorescent dyes.