Preparation and comparison of nonlinear optical properties of MoSe2 with different types of structures

MoSe2 with different types of structures were prepared by a facile solvothermal synthesis method. The structure and morphology characterizations of as-prepared materials indicated that the diameter of MoSe2 hierarchical microspheres was around 1 μm and changed to 500 nm with the assisted-PVP grown up. After composite with graphene, MoSe2 revealed a network structure consisted of nanoflakes with the size of 150 nm. The third-order nonlinear optical properties of the samples were measured by using the Z-scan technique with a picosecond pulse laser at 532 nm. The results showed that all materials had saturable absorption and positive nonlinear refraction properties, and the larger nonlinear optical response had been observed with the addition of surfactant or graphene. The enhancement of the nonlinear optical properties could be affected by structural modification, increased active sites and enhanced charge transfer. The results not only broaden the minds of modified semiconductor materials, but also widen the potential applications of MoSe2 in the areas of mode-locked laser and photonic devices.