Browsing by Author "Subhankar Sarkar"

Now showing 1 - 2 of 2

Silica Nanospheres Coated Silver Islands as an Effective Opto-Plasmonic SERS Active Platform for Rapid and Sensitive Detection of Prostate Cancer Biomarkers
(MDPI, 2022) Anamika Pandey; Subhankar Sarkar; Sumit Kumar Pandey; Anchal Srivastava
The in vitro diagnostics of cancer are not represented well yet, but the need for early-stage detection is undeniable. In recent decades, surface-enhanced Raman spectroscopy (SERS) has emerged as an efficient, adaptable, and unique technique for the detection of cancer molecules in their early stages. Herein, we demonstrate an opto-plasmonic hybrid structure for sensitive detection of the prostate cancer biomarker sarcosine using silica nanospheres coated silver nano-islands as a facile and efficient SERS active substrate. The SERS active platform has been developed via thin (5–15 nm) deposition of silver islands using a simple and cost-effective Radio Frequency (RF) sputtering technique followed by the synthesis and decoration of silica nanospheres (~500 nm) synthesized via Stober’s method. It is anticipated that the coupling of Whispering Gallery Modes and photonic nano-jets in SiO2 nanospheres induce Localized Surface Plasmon Resonance (LSPR) in Ag nano-islands, which is responsible for the SERS enhancement. The as-fabricated SERS active platform shows a linear response in the physiological range (10 nM to 100 μM) and an extremely low limit of detection (LOD) of 1.76 nM with a correlation coefficient of 0.98 and enhancement factor ~2 × 107. The findings suggest that our fabricated SERS platform could be potentially used for the rapid detection of bio-chemical traces with high sensitivity. © 2022 by the authors.
Study of morphological evolution and growth mechanism of CVD grown 2D tin disulfide
(Elsevier B.V., 2023) Rohit Ranjan Srivastava; Subhankar Sarkar; Anchal Srivastava
Fractal patterns formed during non-equilibrium growth processes and are abundant in nature. However, the mechanism of their formation remains unknown. Several growth factors such as relaxation rate, cooling rate, diffusion anisotropy and growth time were identified for regulating the fractal growth. Nevertheless, most articles focused on regular shaped (such as triangles and hexagons) 2D layered metal dichalcogenides (LMDs), whereas fractals have received less attention. Therefore, understanding the controlled synthesis of LMDs materials with unique edge structures is highly desired for various potential applications. Here, we report large fractal growth of tin disulfide (SnS2) by atmospheric pressure chemical vapor deposition technique. The edge length of the atomically thin SnS2 fractals range from 5 to 100 µm. Our study shows the morphological evolution from fractal to triangular-like structure during the CVD growth process. To understand this phenomenon, we anticipated that the early phase of the growth mostly occurs via kinetic regulated pathway resulting fractal like structure. As the domains go through numerous relaxation phases throughout the edge diffusion process, the morphology gets more compact or regular, indicating increased thermodynamic control over the growth process. We have also provided a physical model for the growth mechanism of CVD grown SnS2. © 2023