Hong Kong Polytechnic University

About: Hong Kong Polytechnic University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Computer science & Tourism. The organization has 29633 authors who have published 72136 publications receiving 1956312 citations. The organization is also known as: HKPU & PolyU.

Exceptional catalytic effects of black phosphorus quantum dots in shuttling-free lithium sulfur batteries

Abstract: Lithium sulfur batteries with high energy densities are promising next-generation energy storage systems. However, shuttling and sluggish conversion of polysulfides to solid lithium sulfides limit the full utilization of active materials. Physical/chemical confinement is useful for anchoring polysulfides, but not effective for utilizing the blocked intermediates. Here, we employ black phosphorus quantum dots as electrocatalysts to overcome these issues. Both the experimental and theoretical results reveal that black phosphorus quantum dots effectively adsorb and catalyze polysulfide conversion. The activity is attributed to the numerous catalytically active sites on the edges of the quantum dots. In the presence of a small amount of black phosphorus quantum dots, the porous carbon/sulfur cathodes exhibit rapid reaction kinetics and no shuttling of polysulfides, enabling a low capacity fading rate (0.027% per cycle over 1000 cycles) and high areal capacities. Our findings demonstrate application of a metal-free quantum dot catalyst for high energy rechargeable batteries.

Organic electrochemical transistors integrated in flexible microfluidic systems and used for label-free DNA sensing.

Abstract: enzyme sensors, [ 9 ] DNA sensors, [ 10 ] dopamine sensor, [ 11 ] and cell-based biosensors. [ 12 ] A transistor-based sensor is the combination of a sensor and an amplifi er since a small potential change at an interface can induce a substantial variation of the channel current. [ 16–18 ] Therefore such devices are highly sensitive and potentially low cost. More importantly, OECT can be easily miniaturized and fabricated on fl exible substrates, which is essential for some applications in living systems. OECTs have been integrated in microfl uidic channels and used as ion sensors and enzyme sensors. [ 5 , 6 , 9 ] As for fl exible devices, OECTs were fabricated on fi bers and showed excellent transistor performance. [ 19 , 20 ] However, the application of the fi ber-supported devices in biosensors is limited by solid electrolytes used in the devices. Therefore, we study the OECT integrated in a fl exible microfl uidic system and explore its applications in biosensors, such as DNA sensors. Nucleic acid diagnostics has attracted much interest due to its great scientifi c and economic importance, and it has signifi cant applications in gene expression monitoring, viral and bacterial identifi cation, biowarfare and bioterrorism agents detecting, and clinical medicine. [ 21 ] Besides the traditional technique that is based on the confocal fl uorescence microscope, several different label-free technologies have been developed for the analysis of DNA microarrays, including atomic force microscopy, [ 22 ] electrochemical detection, [ 23 ] surface vibration spectroscopy, [ 24 ] scanning Kelvin probe microscopy (SKPM), [ 25 ]