The nonlinear absorption effects and optical limiting properties of Bi2Te3/rGO thin films

Bismuth telluride/reduced graphene oxide (Bi2Te3/rGO composites) was prepared by solvent-thermal method, and Bi2Te3/rGO-PVA (Polyvinyl alcohol) thin film was synthesized from drop coating method. The third-order nonlinear optical properties (NLO) and optical limiting (OL) performances of the solution samples and the film samples were studied using Z-scan test at the laser wavelength of 532 nm and 1064 nm with 10 Hz repetition frequency and 4 ns pulse width. In comparison with Bi2Te3, rGO and Bi2Te3+rGO (Bi2Te3 and rGO are mechanically stirred together), whether Bi2Te3/rGO solution sample or Bi2Te3/rGO-PVA film sample possess larger third order nonlinear absorption coefficients (β) and lower limiting thresholds due to the charge transfer and synergistic effect between Bi2Te3 and rGO. The limiting thresholds of Bi2Te3/rGO-PVA thin film samples (~0.19 J/cm2 at 532 nm and ~0.52 J/cm2 at 1064 nm) are lower than that of Bi2Te3/rGO solution due to much higher concentration in the film at the same level of linear transmission. The Bi2Te3/rGO-PVA thin film could be the promising optical limiting materials. The photoexcited charge transfer processes of Bi2Te3/rGO heterostructure.Whether in DMSO solution or in PVA thin film, Bi2Te3/rGO composite exhibits better third order nonlinear properties and optical limiting performance than pristine Bi2Te3, rGO and Bi2Te3+rGO sample (Bi2Te3 and rGO are mechanically stirred together) due to the charge transfer and synergistic effect between Bi2Te3 and rGO. [Display omitted] •Preparation of Bi2Te3/reduced graphene oxide (Bi2Te3/rGO) composite and the polyvinyl alcohol (PVA) films.•In situ growth of Bi2Te3 nanosheets on rGO flakes can facilitate the charge transfer.•Bi2Te3/rGO composite shows larger nonlinear absorption coefficient.•The mechanism of the charge transfer between Bi2Te3 and rGO was studied.•The Bi2Te3/rGO-PVA film showed much lower threshold value.