Antimony selenide (Sb2Se3) is a low-toxic, element-abundant, narrow bandgap (Eg = ∼1.1–1.3 eV) semiconductor that shows potential for UV-Visible-Near-infrared optoelectronic applications. This paper reports the use of potassium selenocyanate (KSeCN) as a novel molecular selenium source to synthesize Sb2Se3 uniform nanorods. The resulting nanorods have been carefully characterized and are found to exhibit decent photoconductivity as well as broad-spectrum optical absorption with an Eg value of ∼1.35 eV. A molecular reaction mechanism is rationally proposed and evidenced for forming Sb2Se3, which is related to the thermal decomposition of selenocyanate (SeCN−) anions through the cleaving of Se–CN bonds to elemental Se(0), followed by its reduction to Se2− anions. Our work using KSeCN offers an alternative method for the synthesis of metal selenides with desirable nanostructures and properties.
Zhen Li,Guizhang Guo,Zhou Yu,Zengyue Ma,Yonggang Lei,Libo Yu,Junke Wang
The use of quantum dots (QDs) to sensitize titanium TiO 2 in photoelectrochemical cells (PECs) for solar-driven water splitting represents a highly promising method for converting solar energy into storable chemical energy in the form of hydrogen. The characteristics and interfaces of the QDs play a crucial role in determining the range of light absorption and the efficiency of charge transport and separation upon photoexcitation. Herein, we build CdS x Se 1-x QDs sensitized TiO 2 photoanodes with different amount of Se source by one-step hydrothermal process using thioglycolic acid (TGA) as bifunctional linker. Our results demonstrate that TGA can both anchor QDs to TiO 2 and decompose S for CdS x Se 1-x QDs preparation. The influence of Se source dosage on PEC performance of CdS x Se 1-x /TiO 2 photoanode has been investigated. UV–vis absorption data shows the increase of Se source can enlarge light response range. X-ray photoelectron spectroscopy, transient open-circuit voltage decay and electron lifetime tests indicate proper thickness of SeO 2 which formed on CdS x Se 1-x QDs has the effect to block charges recombination between CdS x Se 1-x /TiO 2 photoanode and electrolyte, improving the electron lifetime of photogenerated electrons. Consequently, the photoelectrochemical cell (PEC) constructed with a CdS x Se 1-x /TiO 2 photoanode, prepared using 0.8 mmol of selenium source, has achieved a photocurrent density of 14.31 mA cm −2 and a photoconversion efficiency of 15.74 %. These results indicate significant potential for the production of green hydrogen.
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