Pradeep’s work is in the area of molecular materials and surfaces. In his formative years, he measured the very first vibrationally resolved photoelectron spectrum of Ar2 and discovered a novel transition metal ion, NiH2+. These days most of his work is on nanomaterials and ice surfaces. His group studied the dynamics of monolayers in monolayer protected nanoparticles and showed that monolayers existed in a rotationally frozen state on nanoparticle surfaces. His group found a ‘transverse electrokinetic effect in which a potential is generated on nanoparticle assemblies anchored on surfaces, when a liquid is flown over them. His group also discovered that in the presence of metal nanoparticles, single walled carbon nanotube (SWNT) bundles emit light in the visible region of the electromagnetic spectrum, irrespective of whether it is metallic or semi-conducting.
His group found that noble metal nanoparticles can completely degrade halocarbons into amorphous carbon and metal halides. This discovery has lead to world’s first nanotechnology based filter for pesticide removal. His group developed several technologies to remove contaminants from drinking water. Combining several such materials, an all-inclusive affordable drinking water purifier has been developed. Exciting aspect of this technology is the creation of advanced materials by simple and environment-friendly methods. This technology is undergoing field trials now. To take such technologies forward, a company has been incubated with the participation of IIT Madras.
A large part of his recent research is on atomically precise clusters. His group discovered several new clusters called quantum clusters or nanomolecules. These have been used for diverse applications ranging from luminescent labels to metal ion sensors.
He and collaborators showed that equilibrium constant of the prototypical proton transfer reaction, NH3 + HCl→NH4Cl, is orders of magnitude lower on ice. Most recently he found that diffusion of chemically similar molecules through ultra thin ice films exhibits several surprises. A new structural transition on the top-most layers of ice surfaces has been discovered at low temperatures. His group showed that ultra-low energy ion collisions at ice surfaces lead to several surprises.