Browsing by Author "Sanju Mahich"

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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.
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.