MoS2 nanosheets covalently functionalized with polyacrylonitrile: synthesis and broadband laser protection performance

Abstract

Highly soluble polyacrylonitrile (PAN)-covalently grafted MoS₂ nanosheets (MoS₂–PAN) were synthesized in situ through reversible addition fragmentation chain transfer (RAFT) polymerization. In comparison with MoS₂ and the MoS₂/PAN blends, whether in solution or in a PMMA matrix, the MoS₂–PAN-based samples show superior optical limiting response in the visible and near-infrared ranges. After annealing at 200 °C in N₂ for 4 hours, the annealed MoS₂–PAN/PMMA film exhibits significantly enhanced nonlinear optical and optical limiting responses when compared to the non-annealed MoS₂–PAN/PMMA film. The observed nonlinear coefficients of the MoS₂–PAN/PMMA film are changed from 1015 cm GW⁻¹ at 532 nm and 534 cm GW⁻¹ at 1064 nm before annealing to 1151 cm GW⁻¹ at 532 nm and 699 cm GW⁻¹ at 1064 nm after annealing. The limiting thresholds were also decreased from 1.98 J cm⁻¹ at 532 nm and 3.60 J cm⁻¹ at 1064 nm before annealing to 1.56 J cm⁻¹ at 532 nm and 2.67 J cm⁻¹ at 1064 nm after annealing.