ABSTRACT
2D materials with mixed crystal phase will lead to the nonuniformity of performance and go against the practical application. Therefore, it is of great significance to develop a valid method to synthesize 2D materials with typical stoichiometry. Here, 2D palladium sulfides with centimeter scale and uniform stoichiometric ratio are synthesized via controlling the sulfurization temperature of palladium thin films. The relationship between sulfurization temperature and products is investigated in depth. Besides, the high-quality 2D PdS2 films are synthesized via sulfurization at the temperature of 450-550 °C, which would be compatible with back-end-of-line processes in semiconductor industry with considering of process temperature. The PdS2 films show an n-type semiconducting behavior with high mobility of 10.4 cm2 V-1 s-1 . The PdS2 photodetector presents a broadband photoresponse from 450 to 1550 nm. These findings provide a reliable way to synthesizing high-quality and large-area 2D materials with uniform crystal phase. The result suggests that 2D PdS2 has significant potential in future nanoelectronics and optoelectronic applications.
ABSTRACT
An imidazolium based ionic liquid was successfully prepared and used as an organic ligand to coordinate with Zn2+ to prepare trapezoidal metal-organic frameworks (Zn-MOF) nanosheets. Then, gold nanoparticles (AuNPs) were integrated onto Zn-MOF nanosheets surface to produce AuNPs@Zn-MOF nanocomposites by in-situ reduction of chloroauric acid. AuNPs with size less than 5 nm were uniformly dispersed on the entire surface of Zn-MOF nanosheets. AuNPs can significantly promote the photocurrent response of Zn-MOF nanosheets and supply an efficient photoelectrochemical sensing platform for fabricating an immunosensor for alpha-fetoprotein (AFP). For AFP determination, the photocurrent response of the immunosensor was linearly related to the logarithm of AFP concentration in the range of 0.005-15.0 ng/mL. The detection limit was calculated to be 1.88 pg/mL. The PEC immunosensor can be facilely fabricated, and provided some superior analytical characteristics such as excellent selectivity, sensitivity, stability and reproducibility for AFP determination. Practicability of the photoelectrochemical immunosensor was demonstrated by using it in assaying AFP in clinical serum samples.
Subject(s)
Biosensing Techniques , Ionic Liquids , Metal Nanoparticles , alpha-Fetoproteins , Gold , Reproducibility of Results , Immunoassay , ZincABSTRACT
In this paper, we use a phoxonic crystal (PxC) which can control the topological states of light and sound by breaking inversion symmetry and thus make it possible to achieve rainbow trapping of light and sound simultaneously. It is shown that topologically protected edge states can be obtained at the interfaces between PxCs with different topological phases. Thus, we designed a gradient structure to realize the topological rainbow trapping of light and sound by linearly modulating the structural parameter. In the proposed gradient structure, the edge states of light and sound modes with different frequencies are respectively trapped at different positions, owing to near zero group velocity. The topological rainbows of light and sound are simultaneously realized in one structure, which open a new, to the best of our knowledge, view and provide a feasible platform for the application of the topological optomechanical devices.
