Controllable synthesis: Bi2S3 nanostructure powders and highly textured polycrystals

Abstract

Uniform Bi2S3 nanostructured powders with a preferential [001] orientation, including nanotubes, nanorods, and nanowires, were synthesized by hydrothermal synthesis using Bi(NO3)3 and Na2S as raw materials, CO(NH2)2 as a pH modifier and ethanediol (C2H6O2) as solvent. The growth mechanism of the Bi2S3 nanostructure in hydrothermal process was investigated. The precursor nanostructures of Bi2S3 single crystal powders were maintained in the Bi2S3 bulk after spark plasma sintering (SPS) at 673 K for 5 min, thereby the highest texture degree F(h k 0) = 0.82 was reached for the sample sintered by using nanotubes as precursor powders, which is much higher than 0.18 for the sample sintered by using the powder prepared by mechanical alloying. The present result suggests that direct sintering of the orientated single crystal powders by applying SPS technique is easy to provide a highly textured Bi2S3 bulk, which benefits include enhanced electrical transport property.