A5033182494- Force Microscopy Techniques and Applications
- Mechanical and Optical Resonators
- Near-Field Optical Microscopy
- Integrated Circuits and Semiconductor Failure Analysis
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Conducting polymers and applications
- Perovskite Materials and Applications
- Advanced MEMS and NEMS Technologies
- Legal Systems and Judicial Processes
- Advanced biosensing and bioanalysis techniques
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Alzheimer's disease research and treatments
- Nanowire Synthesis and Applications
- Analytical Chemistry and Sensors
- Law, Economics, and Judicial Systems
- 2D Materials and Applications
- Cellular Mechanics and Interactions
- Chalcogenide Semiconductor Thin Films
- ZnO doping and properties
- Metal and Thin Film Mechanics
- Semiconductor Quantum Structures and Devices
- Judicial and Constitutional Studies
- Lipid Membrane Structure and Behavior
Northwestern University
2014-2025
National Institute of Technology Sikkim
2023
Evanston Hospital
2022
International Institute for Nanotechnology
2009-2012
Nebraska Wesleyan University
2012
Agency for Science, Technology and Research
2009
Nuance Communications (Austria)
2004-2008
Institute of Nanotechnology
2005
University at Albany, State University of New York
2000-2002
Albany State University
2002
The unique hybrid nature of 2D Ruddlesden-Popper (R-P) perovskites has bestowed upon them not only tunability their electronic properties but also high-performance devices with improved environmental stability as compared to 3D analogs. However, there is limited information about inherent heat, light, and air how different parameters such the inorganic layer number length organic spacer molecule affect stability. To gain deeper understanding on matter we have expanded family R-P perovskites,...
Fibrosis is a hallmark of aging tissues which often leads to altered architecture and function. The ovary the first organ show overt signs aging, including increased fibrosis in ovarian stroma. How this affects biomechanics underlying mechanisms are unknown. Using instrumental indentation, we demonstrated quantitative increase stiffness, as evidenced by an Young's modulus, when comparing ovaries from reproductively young (6-12 weeks) old (14-17 months) mice. This stiffness was dependent on...
A promising approach for detecting biomolecules follows their binding to immobilized probe molecules on microfabricated cantilevers; causes surface stresses that bend the cantilever. We measured this deflection, which is order of tens nanometers, by embedding a metal-oxide semiconductor field-effect transistor (MOSFET) into base cantilever and recording decreases in drain current with deflections as small 5 nanometers. The gate region MOSFET responds thus embedded silicon nitride so avoid...
A nondestructive imaging method, scanning near-field ultrasound holography (SNFUH), has been developed that provides depth information as well spatial resolution at the 10- to 100-nanometer scale. In SNFUH, phase and amplitude of scattered specimen wave, reflected in perturbation surface acoustic standing are mapped with a probe microscopy platform provide nanoscale-resolution images internal substructure diverse materials. We have used SNFUH image buried nanostructures, perform subsurface...
Gold nanoparticles (GNPs) conjugated with biomolecules are promising building blocks for assembly into nanostructured functional materials developing biomarker platforms because of their size dependent optical and electrical properties. Biocompatible GNPs were synthesized using glutamic acid as a reducing agent the interaction between bovine serum albumin (BSA) was investigated fluorescence circular dichroism (CD) spectroscopies. The binding constant (Kb) protein to determined by measuring...
A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of and short diffusion distance between electrodes give an ultra-high areal capacitance 56.3 mF cm−2 at a density 27.2 μA cm−2.
The power conversion efficiency (PCE) of halide perovskite solar cells is now comparable to that commercial cells. These are generally based on multication mixed-halide absorbers with nonideal band gaps 1.5-1.6 eV. PCE should be able rise further if the could use narrower-band gap (1.2-1.4 eV). Reducing Pb content semiconductors without sacrificing performance also a significant driver in cell research. Here, we demonstrate mixed Pb/Sn-based perovskites containing oversized...
Two-dimensional (2D) layered hybrid organic–inorganic perovskites (HOIPs) have demonstrated improved stability and promising photovoltaic performance. The mechanical properties of such functional materials are both fundamentally practically important to achieve high performance mechanically stable (flexible) devices. Here, we report the a series 2D lead iodide HOIPs investigate role structural subunits (e.g., variation length organic spacer molecules, R number inorganic layers, n) in...
The efficient preparation of single-crystalline ionic polymers and fundamental understanding their structure-property relationships at the molecular level remains a challenge in chemistry materials science. Here, we describe single-crystal structure highly ordered polycationic polymer (polyelectrolyte) its proton conductivity. polyelectrolyte single crystals can be prepared on gram-scale quantitative yield, by taking advantage an ultraviolet/sunlight-induced topochemical polymerization, from...
Mechanical stability of hybrid organic-inorganic perovskites (HOIPs) is essential to achieve long-term durable HOIP-based devices. While HOIPs in two-dimensional (2D) form offer numerous options the structure and composition tune their mechanical properties, little known about structure-mechanical-property relationship this family materials. Here, we investigated a series 2D lead halide by nanoindentation explore impact critical factors controlling properties both organic inorganic layers on...
Utilization of in situ/operando methods with broad beams and localized probes has accelerated our understanding fluid-surface interactions recent decades. The closed-cell microchips based on silicon nitride (SiN x ) are widely used as “nanoscale reactors” inside the high-vacuum electron microscopes. However, field been stalled by high background scattering from encapsulation (typically ~100 nanometers) that severely limits figures merit for situ performance. This adverse effect is...
Zinc sulphide nanoparticles in the size range ∼10–40 Å diameter have been synthesized using aqueous chemical method. Scanning tunneling microscopy showed that particles are indeed nanosize particles. The dependent band gap could be varied from a bulk value of 3.68 to 4.5 eV. X-ray diffraction indicated crystalline except for those with ∼4.5±0.1 Nanoparticles particle ∼21×2 or energy 4.1×0.1 eV were doped manganese. photoluminescence peak at ∼600 nm corresponding yellow light emission was...
Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) are recent members of the 2D materials family with wide tunability, highly dynamic structural features, and excellent physical properties. Ultrathin HOIPs their heterostructures other have been exploited for study phenomena device applications. The in-plane mechanical properties ultrathin critical understanding coupling between fields integrated devices Here we report freestanding lead iodide perovskite membranes dependence on...
In photovoltaics and flexible electronics applications, two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs) are often subjected to mechanical strain arising from materials processing, device functioning, thermal expansion. Here we report for the first time a study of band gap response uniaxial tensile in thin 2D HOIP flakes with general formula (CH3(CH2)3NH3)2(CH3–NH3)n−1PbnI3n+1. At large n (n > 3), will increase as increases, can be high 13.3 meV/% = 5, which is due rotation...
We demonstrate a facile approach for site-specific fabrication of organic, inorganic, and hybrid solid-state nanostructures through novel combination electron-beam lithography (eBL) spin coating liquid sol-gel precursors, termed soft eBL. By using eBL patterned resists as masks in with low cost process such coating, directed growth controlled dimensions is achieved without the need costly difficult step etching ceramics. The highly versatile nature scheme highlighted variety materials...
The alarming increase in the amount of dangerous pesticides such as atrazine agricultural fields and drinking water is driving growth new technologies to detect these toxins well below their threat level. recent elucidation microcantilever nanomechanical bending response chemical biomolecular interactions has added another significant facet biochemical engineering research fostered development a variety signal detection paradigms, at both microscale nanoscale. We report label-free highly...
Tracking the uptake of nanomaterials by living cells is an important component in assessing both potential toxicity and designing future materials for use vivo. We show that difference local elasticity at site silica (SiO2) nanoparticles confined within a macrophage enables functional ultrasonic interactions. By elastically exciting cell, phase perturbation caused buried SiO2 was detected used to map subsurface populations nanoparticles. Localization mapping stiff chemically synthesized...
The endothelial cell (EC) lining of the pulmonary vascular system forms a semipermeable barrier between blood and interstitium regulates various critical biochemical functions. Collectively, it represents prototypical biomechanical system, where complex hierarchical architecture, from molecular scale to cellular tissue level, has an intimate intricate relationship with its biological We investigated mechanical properties human artery cells (ECs) using atomic force microscopy (AFM)....
Structural defects and heterogeneities play an enormous role in the formation of localized hot spots 2D materials used a wide range applications from electronics to energy systems. In this report, we employ scanning thermal microscopy (SThM) spatially map temperature rise across various titanium carbide (Ti3C2T x; T stands for surface terminations) MXene nanostructures under high electrical bias with sub-50 mK resolution sub-100 nm spatial resolution. We investigated several Ti3C2T x flakes...
Water contamination by harmful chemicals is a growing global concern, creating need to develop technologies that can detect range of target compounds at the required concentrations. Here, we address this merging biological allosteric transcription factors with DNA-coated nanomechanical microcantilevers in water digital readout. After proof-of-concept demonstration and optimization anhydrotetracycline TetR factor, use CadC factor Pb2+ Cd2+ concentrations down 2 1 ppb, respectively, less than...