My postdoctoral research centers on the design, development, and characterization of advanced nanomaterials, with a focus on creating consistent, high-performance materials through precise control over their structural and electronic properties. By addressing challenges in material consistency and reproducibility, I aim to develop nanostructured materials with superior functionality across various applications.
1. Development of Nanostructured Materials:
I have successfully developed Ag@Au nanohybrids, embedding ultrasmall silver nanoparticles (of size ~ 2 nm) in a gold matrix. These materials exhibit highly tunable structural and electronic properties, achieved by optimizing particle size, distribution, and interfacial properties. This research emphasizes controlling nanostructured interfaces to achieve consistent electronic performance and superior material stability.
2. Reliable Material Production:
A significant focus of my work is on ensuring that the materials I develop maintain consistent properties across different batches and synthesis conditions. By carefully controlling synthesis parameters, I have optimized the size distribution and surface morphology of these nanohybrids, ensuring reproducibility and consistent performance, particularly in their transport properties.
3. Advanced Characterization:
I use a range of advanced characterization techniques, including high-resolution TEM (HRTEM), STEM, and EELS, to analyze the microstructure, atomic composition, and interface properties of the materials. These methods provide critical insights into the nanoscale structural details, allowing me to refine the synthesis process and enhance the electrical and thermal transport properties. Additionally, X-ray Photoelectron Spectroscopy (XPS) is employed to investigate the charge state of Ag and Au in the nanohybrids, which plays a crucial role in understanding the material’s potential for superconductivity by revealing the chemical environment and electron-phonon coupling at the interfaces. I also use X-ray Diffraction (XRD) to confirm the crystal structure and identify the proper structural phase necessary for superconductivity, ensuring phase purity and alignment with theoretical models. By combining these techniques, I can establish a clear correlation between the structural phase and the electronic properties, guiding further optimization of the materials.
4. Transport Properties and Electron-Phonon Coupling:
My research has demonstrated that these nanohybrids exhibit nonclassical transport properties due to enhanced electron-phonon coupling (EPC). By embedding Ag nanoparticles within the Au matrix, I have observed significant deviations from traditional metallic transport behavior, resulting in strong EPC. This tunable electron-phonon interaction opens up new possibilities for the development of materials with tailored electrical properties, particularly for applications where energy dissipation and conductivity are crucial.
For Details:
T. Maji et al. Implications for Interface-Enabled Functionality” ACS Appl. Electronic Mater. 5 (2023) 2893.
T. Maji et al. Engineering ultra-strong electron-phonon coupling and nonclassical electron transport in crystalline gold with nanoscale interfaces ” Nat. Commun. (In press)
The main motive of my research work is focused on two parts:
I used to synthesized novel nanohybrid material in our AOSL lab. We use spectroscopic tools (including excited state time-resolved spectroscopy) to tune the hybrid system to enhance multifunctional applications.
On the other hand, we use computational calculations (using DFT as implemented in VASP, or TDDFT) to understand the electronic properties of the interface of the hybrid systems. We calculate the device performance of the hybrid system using the NEGF method as implemented ATK software.
One of the main objectives of the work is to develop oxide-based hybrid material using combined spectroscopic and computational tools. We have studied the change of activity of nanohybrid after modulation of the system from the pristine one. The interfacial dynamics of the system have been explored using ultrafast spectroscopic tools and computational calculations.
For Details:
T. Maji et al. Applied Catalysis A, 583, (2019), 117124
T. Maji et al. Journal of Photochemistry Photobiology A, 332, (2017), 391
T. Maji et al. Journal of Photochemistry Photobiology A, 397, (2020), 112575
Another key objective of the thesis is exploring the engineered electronic properties of Graphene analogous transition metal dichalcogenide (TMDC) based heterostructure after using theoretical as well as experimental tools. We have enquired about the charge transfer property and doping nature of TMDC based heterostructure system. Electronic properties of 2D heterostructures (MoSe2/GO and MoS2/TiO2) have been investigated for potential device application.
For Details:
T. Maji et al. ACS Applied Material and Interfaces , 12, (2020), 44345
T. Maji et al. Physical Review B, 99, (2019), 115309
T. Maji et al. Physical Review Material, 5, (2021), 054006
Using different computational techniques, including density functional theory (DFT), time-dependent DFT (TDDFT), phonon, and DFT-coupled quantum transport we have investigated the properties of different topological systems and bimetallic heterostructures. We have designed nano-heterostructure of Drude metals (Au/Ag) and interfaces of Drude metal/Weyl semimetal systems having novel correlated attributes leading to intriguing electronic and optical properties.
For Details:
T. Maji et al. Physical Chemistry Chemical Physics, 22, (2020), 16314
T. Maji et al. Scieinctific Report, 10, (2020), 1-12
Organic-inorganic nanohybrid can be used in various fields including solar light harvesting, drug delivery systems, enhanced medicinal activity, sensing application, etc. We developed a simple, efficient, and field-deployable method to decontaminate the toxic heavy metals from food additives. Moreover, we have prepared different hybrid systems for enhanced medicinal activity also.
For Details:
T. Maji et al. RSC Advances, 10, (2020), 38890
T. Maji et al. Journal of Material Science B, 5, (2017), 3927