Functionalized hBN\nQuantum Dots as Optical Limiters\nin the Ultraviolet Region

Hexagonal boron nitride (hBN) quantum dots (QDs) have\nbeen synthesized\nusing a top-down method. Pristine QDs exhibit wavelength-dependent\nemission spectra. The nonlinear optical (NLO) behavior of hBN QDs\nhas been investigated for the first time using the self-diffraction\ngeometry of the four-wave mixing technique and z-scan method. The\noptical properties are modified upon functionalization with suitable\nthiol (−SH) and aromatic amine (−NHR) ligands. It has\nbeen found that the spectroscopic and NLO responses are influenced\nby the transfer of charge carriers between the ligand and base hBN\nmoiety. Functionalized QDs give rise to red-shifted emission and possess\nan enhanced NLO response. QDs show a promising optical limiting response,\nwhich makes them useful as a coating in protective eyewear for intense\nlasers.