Phase-Controlled Synthesis of High-Bi-Ratio Ternary Sulfide Nanocrystals of Cu1.57 Bi4.57 S8 and Cu2.93 Bi4.89 S9

Xiaoru Ren; Long Yuan; Qingshuang Liang; Renguo Xie; Zhibin Geng; Yu Sun; Lei Wang; Keke Huang; Tianli Wu; Shouhua Feng

doi:10.1002/cplu.201800271

Phase-Controlled Synthesis of High-Bi-Ratio Ternary Sulfide Nanocrystals of Cu_1.57 Bi_4.57 S₈ and Cu_2.93 Bi_4.89 S₉

Chempluschem. 2018 Aug;83(8):812-818. doi: 10.1002/cplu.201800271.

Authors

Xiaoru Ren¹, Long Yuan¹, Qingshuang Liang², Renguo Xie¹, Zhibin Geng¹, Yu Sun¹, Lei Wang³, Keke Huang¹, Tianli Wu⁴, Shouhua Feng¹

Affiliations

¹ State Key Laboratory of Inorganic Syntheses and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China.
² College of Chemistry and Chemical Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China.
³ Inorganic Syntheses and Applied Chemistry, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
⁴ School of Physics, Chongqing University, Shapingba, Chongqing, 401331, China.

PMID: 31950663
DOI: 10.1002/cplu.201800271

Abstract

High Bi-ratio ternary sulfides have been recently reported as superior thermoelectric materials. However, the synthesis of high Bi-ratio Cu-Bi-S nanocrystal remains a challenge. Reported here are the synthesis and characterization of three-phase Cu-Bi-S nanocrystals with the nominal chemical formulae of Cu_1.57 Bi_4.57 S₈ , Cu_2.93 Bi_4.89 S₉ and Cu₃ BiS₃ . The samples were prepared using a Bi₂ S₃ precursor by varying the amount and type of Cu_2-x S (i. e. Cu₂ S or Cu_7.2 S₄ ) reactants. TEM images reveal that two new samples crystalized having nanorod morphology with radii of approximately 50 nm and lengths of 200 nm. XPS results indicate that the valence states of Bi in both the two new phases are +3 with viable oxidation states for Cu. UV-Vis-NIR absorption spectroscopy reveals that narrow direct bandgaps are 1.12 and 1.27 eV for Cu_1.57 Bi_4.57 S₈ and Cu_2.93 Bi_4.89 S₉ , respectively. Besides, this method could also be applied to synthesize the Cu₃ BiS₃ phase with a new nanoplate morphology. The as-synthesized Cu-Bi-S samples show Cu/Bi ratio-dependent photoresponsive properties. This study not only reports the structure and bandgap of two ternary sulfides, which have only been discovered in the mineral previously, but also provides an efficient method for synthesizing Bi-rich ternary chalcogenide nanocrystals.

Keywords: Bismuth; hot injection method; metal-sulfide precursors; nanocrystals.

Abstract

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