Complicated and Unconventional Defect Properties of the Quasi-One-Dimensional Photovoltaic Semiconductor Sb2Se3

It was expected that the properties of intrinsic point defects would be simple in the binary semiconductor Sb₂Se₃. However, we show using first-principles calculations that the intrinsic defects in this quasi-one-dimensional (Q1D) semiconductor are unexpectedly complicated and different from those in conventional photovoltaic semiconductors such as CdTe or GaAs. First, the same type of defects located on non-equivalent atomic sites can have very different properties due to the low symmetry of the Q1D structure, which makes the properties of point defects complicated, even though there are only a few point defects. Second, uncommon defects such as the cation-replace-anion antisite Sb_Se, anion-replace-cation antisite Se_Sb, and even two-anion-replace-one-cation antisite 2Se_Sb, which are difficult to form in CdTe and GaAs, can have high concentrations and even be dominant in Sb₂Se₃ due to the weak van der Waals interactions and the large void space between different [Sb₄Se₆] _n atomic chains of the Q1D structure. These defects produce a series of acceptor and donor levels in the band gap and make Sb₂Se₃ p-type under the Se-rich condition but n-type under the Se-poor condition. Five deep-level recombination-center defects are identified, and their formation is difficult to suppress, imposing a serious limit to the development of high-efficiency Sb₂Se₃ solar cells. Our study demonstrates that the defects can be complicated and unconventional in the binary compound semiconductors with low symmetry and Q1D structures, which can be classified as chemically binary while structurally multinary.

Preparation and Enhanced Catalytic Hydrogenation Activity of Sb/Palygorskite (PAL) Nanoparticles

A Sb/palygorskite (PAL) composite was synthesized by a facile solvothermal process and applied in catalytic hydrogenation of p-nitrophenol for the first time. It was found that the Sb nanoparticles with the sizes of 2-5 nm were well dispersed on the fiber of PAL, while partial aggregated Sb nanoparticles with sizes smaller than 200 nm were also loaded on the PAL. The Sb/PAL composite with 9.7% Sb mass amounts showed outstanding catalytic performance by raising the p-nitrophenol conversion rate to 88.3% within 5 min, which was attributed to the synergistical effect of Sb and PAL nanoparticles facilitating the adsorption and catalytic hydrogenation of p-nitrophenol.

Sb2Se3 assembling Sb2O3@ attapulgite as an emerging composites for catalytic hydrogenation of p-nitrophenol

The construction and application of a new type of composite material are achieved more and more attention. However, expected Sb2Se3/attapulgite composites aim to use the low price, and high adsorption of attapulgite in assembling Sb2Se3 is quite difficult to be acquired by a facile and benign environmental hydrothermal method. In this manuscript, we developed a new way for preparation of an emerging composite by means of Sb2O3 as a media linking Sb2Se3 and attapulgite together, and finally won an emerging composite Sb2Se3/Sb2O3@attapulgite, which presented an excellent catalytic properties for catalytic hydrogenation of p-nitrophenol. It was noted that the Sb2Se3/Sb2O3@attapulgite composites exhibited a high conversion rate for the hydrogenation of p-nitrophenol that was up to 90.7% within 15 min, which was far more than the 61.5% of Sb2Se3 sample. The excellent catalytic performance was attributed to the highly dispersion Sb2Se3 microbelts and Sb2Se3@Sb2O3@attapulgite rods, which would improve the adsorption of the reactant species and facility electronic transfer process of the catalytic hydrogenation of p-nitrophenol.

Morphological evolution of hierarchical Bi2Se3/BiOBr nanostructures and enhanced activity for p-nitrophenol reduction by NaBH4

The emerging Bi₂Se₃/BiOBr composite with a flower like microsphere structure prepared by a mild solvothermal method using BiOBr microspheres as a template and presenting an enhanced catalytic activity in the reduction of p-nitrophenol.