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Nano Research

Article Title

Correlation between types of defects/vacancies of Bi2S3 nanostructures and their transient photocurrent

Keywords

Bi2S3 microspheres, nanorod assembly, defects/vacancies, positron annihilation spectrometry, transient photocurrent

Abstract

ABSTRACT Crystalline nanostructures possess defects/vacancies that affect their physical and chemical properties. In this regard, the electronic structure of materials can be effectively regulated through defect engineering; therefore, the correlation between defects/vacancies and the properties of a material has attracted extensive attention. Here, we report the synthesis of Bi2S3 microspheres by nanorod assemblies with exposed {211} facets, and the investigation of the types and concentrations of defects/vacancies by means of positron annihilation spectrometry. Our studies revealed that an increase in the calcined temperature, from 350 to 400 °C, led the predominant defect/vacancy densities to change from isolated bismuth vacancies (VBi) to septuple Bi3+–sulfur vacancy associates (VBiBiBiSSSS). Furthermore, the concentration of septuple Bi3+–sulfur vacancy associates increased as the calcined temperature was increased from 400 to 450 °C. The characterized transient photocurrent spectrum demonstrates that the photocurrent values closely correlate with the types and concentrations of the predominant defects/vacancies. Our theoretical computation, through first principles, showed that VBiBiBiSSSS strongly absorbs I (sol) 2 , easily desorbs I (sol)  , and enhances the electrocatalytic activity of the nanostructures.

Graphical Abstract

Publisher

Tsinghua University Press

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