Scientific inquiries that we undertake
Our contribution to the area of nanoscience is to develop new methodologies to fabricate different hybrid nanomaterials and study their new advanced properties. Hybrid nanomaterials – a unique class of materials that are formed by the integration of two or more materials at the molecular or nanometer length scale – are well known to exhibit fundamentally new properties and phenomena. Our group is interested in preparing hybrid nanostructures based on organic-inorganic, metal-metal and metal-semiconductor nanomaterials. Also, we are interested in studying the new improved properties that are most likely expected to emerge from these nanohybrid systems. Some of the studies that we are examining are:
Self-assembly and aggregation studies: Control over higher order nanostructures:
We are interested in developing general and simple strategies to integrate individual nanocomponents into higher order nanostructures. Our efforts involve the tuning of surface properties of individual nanoparticles, so that their inter-particle interactions can be controlled. Another desire is to achieve a fundamental understanding, and thereby a better control on the various forces involved in the process of nanoparticle self-assembly.
We believe that the ability to control interparticle forces not only improves the existing nanoparticle functionalities but paves the way for newer properties as well. A proof of concept in this direction was demonstrated, wherein the regulation of interparticle forces—revealing controlled aggregation—has been successfully translated into the trapping and scavenging of toxic ions. A perfect balance between the attractive and repulsive forces is achieved by tuning the [+] and [−] ligands on the surface of heterogeneously charged metal NPs.
For more details check: Chem. Mater. 2016, 28, 2348.
Out ultimate aim here is to use our knowledge and ability to control forces to develope living self-assembles systems far from equilibrium based on metal and semiconductor nanomaterials.
Students in-charge: Sumit Roy, Shreya Tyagi.
Nanocatalysis: Control over rate and amount of catalyst
How can one improve the efficiency of a known catalyst in a known catalytic reaction? Is the mechanism invloved in some of the traditional catalytic reactions well understood? These are some of the questions that we are trying to address by controlling the interactions between the catalysts and substrates..
In one example, we have demonstrated the potency of electrostatic effects arising from nanoparticle surface in Au-NP-catalyzed reduction of charged substrates. The electrostatic potential around Au NPs is controlled by varying the nature of ligands and ionic strength of the medium. Favorable interactions arising from the attraction between oppositely charged Au NP and substrates results in the channeling of substrates to the NP surface, which in turn enhances the catalytic reduction.
For more details check: ACS Catal. 2017, 7, 7141.
Students in-charge: Vanshika Jain, Ankit Dhankhar.
Light harvesting studies: Control over optoelectronic properties
Our fundamental aim is to control the interaction between light and nanomaterials by playing with forces, and try to improve various light harvesting properties (like energy & electron transfer, photoconductivity, solar cells etc.)
In one example, we have demonstrated a light induced energy transfer process between cationic environment friendly InP QDs and anionic molecular dye under physiological conditions. The electrostatic attraction between cationic QDs and anionic dyes is responsible for the formation of a strong ground state complex, which resulted in an efficient energy transfer. This is the first example for FRET studies in cationic QDs.
For more details check: Chem. Sci. 2017, 8, 3879 ; ACS Energy Lett. 2019, 4, 1710−1716
The ultimate goal is to utilize the optimized geometries and materials for the fabrication of low cost-high efficient light harvesting devices.
Students in-charge: Pradyut Roy