Shape-controlled synthesis of AgBiS_2 nano-/microstructures using PEG- assisted facile solvothermal method and their functional properties

摘要

Shape-controlled synthesis of AgBiS2 nano-/microstructures by a facile solution-based route is reported. One-dimensional AgBiS2 nano-/microspheres were synthesized through solvothermal method using ethylene glycol as the solvent and polyethylene glycol (PEG) as a soft template. The growth mechanisms related to the morphology control and phase formation of AgBiS2 were discussed. X-ray diffraction results confirmed that the cubic structure of AgBiS2 was formed for 0.04 mol of thiourea in the precursor solution. Raman spectrum of the AgBiS2 revealed the presence of the functional groups. X-ray photoelectron spectroscopy exhibited Ag 3d, Bi 4f and S 2s core levels for AgBiS2, thus confirming the pure and secondary phase of the samples. Field-emission scanning electron microscope and transmission electron microscope analyses exhibited the systematic transformation of agglomerated nanorods into microsphere, due to increase in the thiourea concentration. The vital role played by the thiourea concentration in modifying the morphology of AgBiS2, is discussed. Elemental mapping analysis confirmed the uniform distribution of the elements. The direct optical band gap of AgBiS2 nano-/microstructures vary from 0.98 to 1.01 eV. Synthesized samples were used to deposit thin films on FTO substrate using spray pyrolysis method. The I-V characteristics of the films exhibited ohmic nature and showed high conductivity for the nanorods sample.