Covalent Modification of MoS2 with Poly(N-vinylcarbazole) for Solid-State Broadband Optical Limiters

New soluble MoS2 nanosheets covalently functionalized with poly(N-vinylcarbazole) (MoS2-PVK) were in situ synthesized for the first time. In contrast to MoS2 and MoS2/PVK blends, both the solution of MoS2-PVK in DMF and MoS2-PVK/poly(methyl methacrylate) (PMMA) film show superior nonlinear optical and optical limiting responses. The MoS2-PVK/PMMA film shows the largest nonlinear coefficients ((eff)) of about 917cmGW(-1) at =532nm (cf. 100.69cmGW(-1) for MoS2/PMMA and 125.12cmGW(-1) for MoS2/PVK/PMMA) and about 461cmGW(-1) at =1064nm (cf. -48.92cmGW(-1) for MoS2/PMMA and 147.56cmGW(-1) for MoS2/PVK/PMMA). A larger optical limiting effect, with thresholds of about 0.3GWcm(-2) at =532nm and about 0.5GWcm(-2) at =1064nm, was also achieved from the MoS2-PVK/PMMA film. These values are among the highest reported for MoS2-based nonlinear optical materials. These results show that covalent functionalization of MoS2 with polymers is an effective way to improve nonlinear optical responses for efficient optical limiting devices.