Arun Prakash Upadhyay

Generic Process for Highly Stable Metallic Nanoparticle-Semiconductor Heterostructures via Click Chemistry for Electro/Photocatalytic Applications

Metallic nanoparticles (MNP) are utilized as electrocatalysts, cocatalysts, and photon absorbers in heterostructures that harvest solar energy. In such systems, the interface formed should be stable over a wide range of pH values and electrolytes. Many current nonthermal processing strategies rely on physical interactions to bind the MNP to the semiconductor. In this work, we demonstrate a generic chemical approach for fabricating highly stable electrochemically/photocatalytically active monolayers and tailored multilayered nanoparticle structures using azide/alkyne-modified Au, TiO2, and SiO2 nanoparticles on alkyne/azide-modified silicon, indium tin oxide, titania, stainless steel, and glass substrates via click chemistry. The stability, electrical, electrochemical, and photocatalytic properties of the interface are shown via electrochemical water splitting, methanol oxidation, and photocatalytic degradation of Rhodamine B (RhB) dye. The results suggest that the proposed approach can be extended for the large-scale fabrication of highly stable heterostructure materials for electrochemical and photoelectrocatalytic devices.

Brownian motion retarded polymer-encapsulated liquid crystal droplets anchored over a patterned substrate via click chemistry

Highly sensitive liquid crystalline (LC) materials are promising candidates for sensing applications. Anchoring of liquid crystal (LC) droplets over substrates can reduce the signal broadening due to retarded Brownian motion. In addition, anchoring over patterned substrates can facilitate the precise quantification of spatially resolved detection of analyte. To this end, we report a versatile approach to anchor LC droplets encapsulated within polymer capsules over a patterned substrate via a highly stable triazole linkage created through click chemistry. Confocal and polarized microcopy images confirm the anchoring of LC droplets over the glass substrates. Change in orientation (bipolar to radial) due to the binding of sodium dodecyl sulfate (SDS) surfactant and 1,2-dilauroyl-sn-glycero-3-phosphocholine (L-DLPC) at the LC interface suggests that the sensing capabilities of the Brownian motion-retarded encapsulated LC droplets is retained. It is also demonstrated that the so assembled systems are stable over six months, which makes them potential candidates for portable microfluidic sensors.