Polymer Functionalized Antimony Sulfide Quantum Dots for Broadband Optical Limiting

Antimony sulfide (Sb2S3) quantum dots (SQDs), with an average diameter of 3.22 nm, were prepared via a top-down liquid ultrasonication exfoliation technique. A highly soluble poly(N-vinylcarbazole)-covalently functionalized SQDs (SQDs-PVK) was synthesized in situ by reversible addition fragmentation chain transfer polymerization, and embedded into non-optically active poly(methylmethacrylate) (PMMA) matrix giving the SQDs-PVK/PMMA film.

The annealed SQDs-PVK/PMMA film showed exceptional nonlinear optical performance, with large nonlinear absorption coefficients of 713.71 cm/GW at 532 nm and 913.60 cm/GW at 1064 nm, and small limiting thresholds of 1.44 J/cm2 at 532 nm and 1.08 J/cm2 at 1064 nm. These advantages make SQDs–PVK one of the promising candidates for a broadband optical limiter in both the near-infrared and visible ranges.