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6 results on '"Koffa, J. D."'

2. The Performance Analysis of a Quantum-Mechanical Carnot-like Engine using Diatomic Molecules

Author

Oladimeji, E. O., Ibrahim, T. T., Ikot, A. N., Koffa, J. D., Idundun, V. T., Umeh, E. C., and Audu, J. O.

Subjects
Quantum Physics
Abstract

This study presents an analysis of a quantum mechanical formulation of the Carnot like cycle using diatomic molecules, i.e., the Morse oscillator, as the working substance. The generalized model with an arbitrary one dimensional potential is used to obtain the important performance parameters such as the efficiency, the power output, and the optimal region of the engine by considering well width L moving with a finite speed. The optimal efficiency, the maximum power output, and dimensionless power ranges of the working substance was also determined. The results obtained in this work are found to agree with those obtained for similar engine but with different working substance., Comment: 16 pages, 3 figures

Published
2023

3. The efficiency of Quantum Mechanical Carnot Engine using the Woods Saxon model

Author

Oladimeji, E. O., Ibrahim, T. T., Ikot, A. N., Koffa, J. D., Edogbanya, H. O., Umeh, E. C., Audu, J. O., and Uzer, J. M.

Subjects
Quantum Physics, Mathematical Physics
Abstract

The quantum engine cycle serves as an analogous representation of classical heat engines for microscopic systems and the quantum regime of thermal devices is composed of a single element. In this work, the Quantum-Mechanical properties of a non-linear quantum oscillator described by the Woods-Saxon [WS] model are examined. The Quantum-Mechanical analogue of the Carnot cycle was constructed using changes in both the width L of the well and the quantum state of the potential well. The efficiency of the quantum engine, consisting of adiabatic and isothermal processes based on the Woods-Saxon [WS] potential is derived. The result is shown to be analogous to that of the classical engine and found to agree, within an appropriate limit, with existing results obtained from other potential models. This implies that the [WS] potential can be used as an alternative model in quantum engines., Comment: 12 pages, 1 figure

Published
2022

5. An Absorber Enrichment Study and Implications on the Performance of Lead-Free CsSnI3 Perovskite Solar Cells (PSCs) Using One-Dimensional Solar Cell Capacitance Simulator (1D-SCAPS)

Author

Ahmed, T. O., Ibrahim, T. T., Oladimeji, E. O., and Koffa, J. D.

Abstract

Extensive research efforts have been made over the last few years to proffer solution to the high recombination rate and stability issues associated with Sn-based perovskite solar cells. In line with this, we modeled cesium tin iodide (CsSnI3)–based perovskite solar cell (PSC) with titanium (IV) oxide (TiO2) and copper thiocyanate (CuSCN) as the electron and hole transport materials respectively by employing one-dimensional solar cell capacitance simulator (1D-SCAPS). For the CsSnI3-based PSC, n-i-p planar configuration was employed and previously published relevant data were used for the simulation. The results obtained for the initially modeled PSC compared well with similar devices in the literature. Based on the established relationship between charge carrier lifetime and power conversion efficiency (PCE) of a solar cell, we varied defect density in the cesium tin iodide (CsSnI3) from 1013 to 1017 cm−3 and studied its influence on the performance parameters of the modeled CsSnI3-based PSC. We find that the diffusion length and lifetime of charge carriers are significantly increased with decreasing defect density of the CsSnI3 absorber. In this study, we report that it is possible to significantly reduce the dominated Shockley–Read–Hall (SRH) high recombination rate occurring in CsSnI3 perovskite layer even at a low defect density of 1013 cm−3 by using a combination of SnCl2 and Br− as additive and dopant respectively for CsSnI3 enrichment. This strategy ensured a reduced concentration of Sn4+ vacancy (VSn) in the CsSnI3 absorber and an improved carrier lifetime beyond 0.05 ns as obtained for the initially modeled CsSnI3-based PSC by a magnitude of the order of 103 while the diffusion length was improved from 1.1 µm by a magnitude of the order of 102 for the enriched CsSnI3-based PSC. For the optimized CsSnI3-based PSC, we recorded an open-circuit voltage (VOC) of magnitude 1.289 V, short-circuit current density (JSC) value 32.60 mA∙cm−2, fill factor (FF) 83.56%, and PCE 35.12%. [ABSTRACT FROM AUTHOR]

Published
2024
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6. An Absorber Enrichment Study and Implications on the Performance of Lead-Free CsSnI3Perovskite Solar Cells (PSCs) Using One-Dimensional Solar Cell Capacitance Simulator (1D-SCAPS)

Author

Ahmed, T. O., Ibrahim, T. T., Oladimeji, E. O., and Koffa, J. D.

Abstract

Extensive research efforts have been made over the last few years to proffer solution to the high recombination rate and stability issues associated with Sn-based perovskite solar cells. In line with this, we modeled cesium tin iodide (CsSnI3)–based perovskite solar cell (PSC) with titanium (IV) oxide (TiO2) and copper thiocyanate (CuSCN) as the electron and hole transport materials respectively by employing one-dimensional solar cell capacitance simulator (1D-SCAPS). For the CsSnI3-based PSC, n-i-p planar configuration was employed and previously published relevant data were used for the simulation. The results obtained for the initially modeled PSC compared well with similar devices in the literature. Based on the established relationship between charge carrier lifetime and power conversion efficiency (PCE) of a solar cell, we varied defect density in the cesium tin iodide (CsSnI3) from 1013to 1017cm−3and studied its influence on the performance parameters of the modeled CsSnI3-based PSC. We find that the diffusion length and lifetime of charge carriers are significantly increased with decreasing defect density of the CsSnI3absorber. In this study, we report that it is possible to significantly reduce the dominated Shockley–Read–Hall (SRH) high recombination rate occurring in CsSnI3perovskite layer even at a low defect density of 1013cm−3by using a combination of SnCl2and Br−as additive and dopant respectively for CsSnI3enrichment. This strategy ensured a reduced concentration of Sn4+vacancy (VSn) in the CsSnI3absorber and an improved carrier lifetime beyond 0.05 ns as obtained for the initially modeled CsSnI3-based PSC by a magnitude of the order of 103while the diffusion length was improved from 1.1 µm by a magnitude of the order of 102for the enriched CsSnI3-based PSC. For the optimized CsSnI3-based PSC, we recorded an open-circuit voltage (VOC) of magnitude 1.289 V, short-circuit current density (JSC) value 32.60 mA∙cm−2, fill factor (FF) 83.56%, and PCE 35.12%.

Published
2024
Full Text
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