Browsing by Author "Sarita Kumari"

Now showing 1 - 3 of 3

Bandgap Modulation of Hydrothermally Synthesized CZTS Nanoparticles through Ni Incorporation
(Springer, 2025) Yogesh Kumar Saini; Sanju Mahich; Shubham Gupta; Rishabh Kumar; Chandra Shekhar Pati Tripathi; Anuj Kumar; Sarita Kumari; Sanjay Kumar Swami; Amanpal K. Singh
Kesterite (Cu2ZnSnS4) has gained significant attention in optoelectronic materials research for future solar energy applications due to its composition of earth-abundant elements, nontoxic nature, and cost-effectiveness as a p-type semiconductor material. This study investigates the effect of Ni doping on Cu2Zn1−xSnS4Nix nanoparticles (NPs) synthesized via the hydrothermal method, with varying Ni concentrations (x = 0, 0.005, 0.01, 0.05, 0.1). x-ray diffraction (XRD) and Raman spectroscopy confirm the retention of the kesterite structure with high crystallinity, while x-ray photoelectron spectroscopy (XPS) verifies the incorporation of Ni2+ ions into the Cu2ZnSnS4 (CZTS) lattice. The oxidation states of the Ni+2 metal dopants are clear from the XPS analysis. Field-emission scanning electron microscopy (FESEM) and energy-dispersive x-ray (EDX) analysis reveal changes in particle morphology and elemental distribution due to Ni doping, with FESEM images showing that the particle size of CZTS NPs ranges from 100 nm to 150 nm as the Ni concentration increases. High-resolution transmission electron microscopy (HRTEM) shows clear lattice fringes of both pristine and Ni-doped samples, confirming the crystallinity and highlighting minor distortions in the lattice due to Ni incorporation, which introduces lattice strain. Ultraviolet–visible–near-infrared (UV-Vis-NIR) spectroscopy shows a significant reduction in the optical bandgap from 1.50 eV for pristine CZTS to 1.38 eV for Ni-doped samples, highlighting the importance of bandgap tailoring to optimize CZTS NPs for enhanced solar energy absorption. © The Minerals, Metals & Materials Society 2025.
Comparison of normal saline and balanced crystalloid solution on acid-base and electrolyte balance in emergency neurosurgical trauma patients: A prospective randomised controlled trial
(IP Innovative Publication Pvt. Ltd., 2025) Ambuj Giri; Yashpal Singh; Sarita Kumari; Devesh Shukla; Priyanka Dwivedi; Ravi Shanker Prashad; Saurabh Sagar; Navneeta Bisht; Indresh Yadav
Background: Maintaining cerebral perfusion, controlling brain volume, and providing adequate substrate delivery are the goals of fluid therapy in patients with Traumatic Brain Injury (TBI). While Normal Saline (NS) is frequently used, Balanced Crystalloid Solutions (BCS) like Plasmalyte (PL) offer potential benefits due to their electrolyte composition and decreased risk of hyperchloremic acidosis. This study compares the effects of NS versus BCS on acid-base and electrolyte status in emergency neurosurgical trauma patients. Materials and Methods: A prospective, randomised, double-blinded study was conducted at a tertiary care trauma centre October 2020 to September 2021. One hundred TBI patients undergoing decompressive craniotomy were randomly assigned to receive either NS (Group N) or BCS (Group B) as maintenance fluids. Fluid management was guided by intraoperative needs and arterial blood gases, electrolytes, and urine output were measured pre-operatively, immediately post-operatively, and 6 hours post-operatively. Statistical analysis included ANOVA, paired t-tests, and un-paired t-tests, with a significance level set at p < 0.05. Results: Demographic characteristics and Glasgow Coma Scale (GCS) scores were comparable between groups. Post-operatively, patients in Group B showed a significantly higher pH (7.42 vs. 7.39, p = 0.02) and more stable bicarbonate levels compared to Group N. Lactate levels were closer to normal in Group B. Sodium and chloride levels were higher in Group N, while potassium and calcium levels were more stable in Group B. Urine output was significantly greater in Group B (1341.40 ± 232.70 mL) compared to Group N (1091.0 ± 253.45 mL, p < 0.001). Mortality rates were similar between groups on Day 1. Conclusion: Balanced Crystalloid Solutions as maintenance fluids during the peri-operative period in traumatic brain injury patients result in less electrolyte and acid-base disturbance compared to Normal Saline. However, this did not translate into improved survival outcomes. Further research is needed to confirm these findings and assess long-term impacts on patient recovery. © 2025 The Author(s), Published by Innovative Publications.
Solution-processed CZTS thin films and its simulation study for solar cell applications with ZnTe as the buffer layer
(Springer Science and Business Media Deutschland GmbH, 2023) Bhanu Prakash; Arti Meena; Yogesh Kumar Saini; Sanju Mahich; Amanpal Singh; Sarita Kumari; Chandra Shekhar Pati Tripathi; Banwari Lal Choudhary
Using zinc tellurium (ZnTe) as the buffer layer in the Cu2ZnSnS4 (CZTS)-based solar cells showed an improvement in overall efficiency. ZnTe is investigated as an alternative to replace the conventional toxic Cd-contained buffer layers. It may also reduce the overall cost of these cells as both layers (ZnTe and CZTS) have eco-friendly and earth-abundant constituents. The sol–gel spin coating method is used for the deposition of CZTS thin films on the corning glass substrates. The X-ray diffraction studies showed the peaks corresponding to (112), (200), (220), and (312) planes which confirmed the formation of the essential kesterite phase. The optical band gap of the deposited films was found at around 1.45 eV by the UV–visible-NIR spectrophotometer. The optimum thickness of the absorber layer (CZTS) and buffer layer (ZnTe) was investigated based on the performance of the ZnO:Al/ZnO/ZnTe/CZTS/Mo cell structure by using the AMPS-1D simulation tool. In contrast, the tool was molded by the experimentally investigated data for the constituent materials of the cell structure. The solar cells’ efficiency was increased by 23.47% at 2500 nm and 50 nm thickness of the CZTS and ZnTe layers, respectively. In addition, it was analyzed and found that the current density value showed an improvement with operating temperature as it is one of the requirements in the high solar radiation areas where the temperature even rises more than 50 °C in the summer. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.