Browsing by Author "Shahinuzzaman, Md."

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Green Synthesis of Lead Sulphide Nanoparticles for High-Efficiency Perovskite Solar Cell Applications
(Daffodil International University, 2022-06-05) Islam, Mohammad Aminul; Dilip Kumar Sarkar, Dilip Kumar; Shahinuzzaman, Md.; Wahab, Yasmin Abdul; Khandaker, Mayeen Uddin; Tamam, Nissren; Sulieman, Abdelmoneim; Amin, Nowshad; Akhtaruzzaman, Md.
In this study, lead sulfide (PbS) nanoparticles were synthesized by the chemical precipitation method using Aloe Vera extract with PbCl2 and Thiourea (H2N-CS-NH2). The synthesized nanoparticles have been investigated using x-ray diffraction (XRD), UV-Vis, energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD and TEM results confirm that the films are in the cubic phase. The crystallite size, lattice constant, micro-strain, dislocation density, optical bandgap, etc. have been determined using XRD and UV-Vis for investigating the quality of prepared nanoparticles. The possible application of these synthesized nanoparticles in the solar cells was investigated by fabricating the thin films on an FTO-coated and bare glass substrate. The properties of nanoparticles were found to be nearly retained in the film state as well. The experimentally found properties of thin films have been implemented for perovskite solar cell simulation and current-voltage and capacitance-voltage characteristics have been investigated. The simulation results showed that PbS nanoparticles could be a potential hole transport layer for high-efficiency perovskite solar cell applications.
Prevalence of Economic Exploitations and Their Determinants Among Child Labourers in Dhaka City, Bangladesh
(Daffodil International University, 2021-09-27) Islam, M. Rezaul; Ali, Md. Mokter; Khan, Mohammad Asif; Shahinuzzaman, Md.; Haque, Md. Imdadul; Abusaleh, Kazi
Taking unjust and unlawful benefits of children’s labour for someone’s gain or gratification can be termed as economic exploitations in child labour. The study aimed to explore the prevalence of economic exploitations and their determinants among child labourers (CLs). Lalbagh, Hazaribagh, and Kamrangirchar sub-districts of Dhaka district were rationally chosen as the areas of the study. The study adopted a mixed-method design, where a proportional probability sampling was used. A list of 1753 CLs comprising 543, 587 and 626 from the selected study areas was prepared through a short enumeration survey and 324 CLs were interviewed systematically from the list to collect quantitative data using a face-to-face structured interview schedule. The study also collected qualitative data through 15 in-depth case interviews (five from each sub-district). Multivariate logistic regression was employed to determine the associated factors with the economic exploitations. Thematic analysis was followed, and then a concurrent technique was employed for data analysis. Results showed that 97% of the CLs were economically exploited. The multivariate logistic regression analysis identified that the socio-economic and occupational factors were significantly associated with these economic exploitations in different variables used in the study. On the other hand, the qualitative findings showed that the CLs were physically and verbally abused, engaged long working hours with less than minimum wage, involved in various hazardous jobs while hardly received treatment costs due to occupational injury. Finding would be an important guideline for the governmental and non-governmental organizations, policymakers, human rights workers and development practitioners in the related field.
Recent progress on the efficiency and stability of lead-free Cs₂AgBiBr₆ double halide perovskite solar cells
(Institute of Physics, 2024-12-27) Jakir Hossen, Md.; Hamzah, H.M.; Shahinuzzaman, Md.; Jamal, M.S.; Mohd Said, S.; Hatta, S.F.W.M.; Helal Miah, Md.; Islam, M.A.
Within a decade, the power congversion efficiency (PCEs) of metal-halide perovskite solar cells (PSCs) moves upward from 3.9% to 25.7%, making them competitive with current state-of-the-art silicon-based counterparts. This steepest growth of the PCEs suggests that the commercialization of this technology might be easing the energy transition from fossil fuel to renewable energy. However, a wide range of factors restrict the commercial viability of PSCs like their toxicity and instability. A crucial and difficult task in the field of PSCs is the replacement of Pb-based perovskite with non-toxic and eco-friendly material while maintaining high-performance with improved stability. Cs2AgBiBr6 halide double perovskites (HDP) material seems to be very promising in this regard. This article reviews the recent progress in Cs2AgBiBr6 double PSC devices, especially fabrication techniques including the advancement of its efficiency and stability. Here, the evolution of Cs2AgBiBr6 towards the application and fabrication of PSCs has also been discussed. This study also analyzed the impact of numerous environmental stresses, such as mechanical, thermal, and optical stresses including the potential prospects in the case of Pb-free PSCs.