Search

Nickel selenide with the single-phase structure has been widely studied as counterelectrode nanomaterials for dye-sensitized solar cells (DSCs). However, the effect mechanism of the crystalline structure on the electrocatalytic activity is still needed to be explored and analyzed in nickel selenide with hybrid structure. Therefore, NiSe/NiSe2 hybrid nanomaterials are synthesized via a simple solvothermal approach in this work. NiSe/NiSe2 counterelectrodes are constructed by spraying NiSe/NiSe2 hybrid nanomaterials onto fluorine-doped tin oxide glass. The hybrid nanostructure of NiSe/NiSe2 counterelectrodes exhibits the more catalytic active sites, strong charge separation, and transfer ability for the reduction of triiodide owing to the well-controlled crystalline structure of nickel selenide. Therefore, the results from electrochemical measurements prove that the electrocatalytic activity of the optimized NiSe/NiSe2 counterelectrode is higher than that of platinum electrode. As a result, the DSC with the optimized NiSe/NiSe2 counterelectrode yields a remarkable photoelectrical conversion efficiency of 7.78%, which is larger than that of the DSC based on platinum electrode (7.09%). Our research work provides the insight into design and construct of nickel selenide counterelectrodes of DSCs. [ABSTRACT FROM AUTHOR]

MoS2 nanomaterial has unique properties, including innate affinity with ss-DNA and quenching ability for fluorescence dyes. Here, we present the development of a simple fluorescence biosensor based on water-soluble MoS2 nanosheets and restriction endonuclease BstUI for methylation analysis of p16 promoter. The biosensing platform exhibited excellent sensitivity in detecting DNA with a linear range of 100 pM~20 nM and a detection limit of 140 pM. More importantly, our method could distinguish as low as 1% difference in methylation level. Compared with previous methylation analysis, our design is both time saving and simple to operate, avoiding the limitations of PCR-based assays without compromising performance. [ABSTRACT FROM AUTHOR]

The WS2 nanosheet, a two-dimensional layered nanomaterial, shows high fluorescence quenching ability for the dye-labeled ssDNA. Currently, most of the fluorescent DNA detection methods employ DNA as a probe for recognition of target DNA. Peptide nucleic acid (PNA) is a D N A mimic but a neutral molecule, showing superior hybridization properties to target DNA. Based on the unique properties of WS2 nanosheet and PNA-DNA hybridization, we have developed a rapid, simple, stable and sensitive approach for DNA detection based on good fluorescence quenching ability of the WS2 nanosheet as well as high binding affinity and specificity of PNA to DNA. This novel assay is capable of exhibiting high sensitivity and specificity with a detection limit of 500 pM, and discriminating between single bases. [ABSTRACT FROM AUTHOR]