Solvothermal synthesis and study of nonlinear optical properties of nanocrystalline thallium doped bismuth telluride

Nanocrystalline Bismuth telluride and thallium (4 mol %) doped Bismuth telluride were synthesized through hydrothermal method. The as-prepared products were characterized using Powder X-ray Diffraction, High Resolution Transmission Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, UV–Visible spectroscopy and Fourier Transform Infrared Spectroscopy. Powder XRD results revealed the crystalline nature of the obtained phases. HRTEM showed the particle-like morphology of the products. The decrease in the absorption coefficient due to thallium doping was observed in FTIR spectra. The intensity dependent nonlinear optical properties of nanocrystalline bismuth telluride and thallium doped bismuth telluride were studied using the Z-scan technique in open-aperture configuration. Bismuth telluride doped with thallium showed enhanced nonlinear optical response compared to pristine bismuth telluride and hence could be used as a potential candidate for optical power limiting applications.

Graphical AbstractNonlinear transmission (Z-scan) curves of nanocrystalline bismuth telluride (Δ) and thallium doped bismuth telluride (□). Thallium doped bismuth telluride showed enhanced nonlinear absorption compared to bismuth telluride. Inset: TEM micrograph of bismuth telluride nanocrystallites.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of Nanocrystalline Bi2Te3 and Thallium doped Bi2Te3 through solvothermal method.
► Reduced absorption coefficient due to thallium doping found from IR spectroscopy.
► Open-aperture Z-scan technique for nonlinear optical studies.
► Two photon absorption based model for theoretical fitting of Z-scan data.
► Enhanced nonlinear absorption in Thallium doped Bi2Te3 – potential candidate for optical power limiting applications