Nonlinear absorption, nonlinear scattering, and optical limiting properties of carbon nanotube/molybdenum diselenide organic glass

Because MoSe2 has broadband saturable absorption, and higher nonlinear refractive index. Compared with MoS2, thin-layered MoSe2 possesses very attractive properties, including narrow bandgap, low optical absorption coefficient, and large spin-splitting energy at the top of the valence band. The narrow bandgap and low optical absorption coefficient could make MoSe2 more applicable than MoS2. And the tunable excitation photoelectric effecthas great potential applications in the fields of photoluminescence, phototransistor, solar cells, nonlinear optics and other aspects. However, pure MoSe2 has high photogenerated recombination rate, thus limiting its applications in some optical fields. By designing nanocomposites of MoSe2, the photogenerated recombination rate of these materials can be reduced and their application field can be broadened. In this work, MoSe2 nanocomposites are prepared by simple methods. The two-dimensional layered MoSe2 nanosheets are combined with nanorods. By integrating the surface effect, small size effect and interfacial effect of CNT, the optical nonlinearity and optical limiting performance of MoSe2 composites are improved. The CNT/MoSe2 composite nanomaterials are first synthesized based on narrower band gap and lower light absorption coefficient of MoS2 than those of MoSe2 by growing MoSe2 nanoparticles on the surface of CNT through a solvothermal method, and then is dispersed in methyl methacrylate (MMA) to prepare an organic glass by a casting method, and the MMA is polymerized into poly (methyl methacrylate) (PMMA). The nonlinear absorption (NLA), nonlinear scattering (NLS) and optical limiting (OL) properties of the CNT/MoSe2/PMMA organic glass are studied by the modified Z-scan technique for the first time. The CNT/MoSe2/PMMA organic glass exhibits the saturable absorption (SA) and a changeover from SA to reverse saturable absorption by adjusting input energy. The experimental results show that the CNT/MoSe2/PMMA plexiglass exhibits better anti-saturation absorption and higher optical limiting properties than MoSe2/PMMA and CNT/PMMA plexiglass. Besides, the NLA and OL properties of the CNT/MoSe2/PMMA organic glass are enhanced compared with CNT/PMMA and MoSe2/PMMA organic glasses, which can be attributed to the existence of the C=C double bonds in CNTs, the layered structure of MoSe2 nanosheets, and the interfacial charge transfer between CNTs and MoSe2. And the results demonstrate that the CNT/MoSe2/PMMA organic glass is very promising for optical devices such as optical limiters and mode-locked/Q-switched lasers.