Browsing by Author "Odari, Victor"

Now showing 1 - 4 of 4
  • Publication
    Publication
    Enhanced performance of Sb2S3 mesoscopic sensitized solar cells employing TiO2:Nb compact layer
    (Springer Nature, 2018-07-28) Odari, Victor; Musembi, Robinson; Mwabora, Julius
    This paper reports on the enhancement of charge transport and recombination by niobium doped compact layers of TiO2 in a solar cell with Sb2S3 absorber layer by characterizing both thin films of TiO2:Nb and working solar cell devices with the layer stack FTO/cp-TiO2:Nb/mp-TiO2/Sb2S3/P3HT/MoOx/Ag. The electron transport layers of TiO2 doped with 0.14 and 0.27 at.% Nb were prepared by spin coating and have no structural change as determined from the analysis of GIXRD spectra. SEM images show thin pin hole free layers of the cp-TiO2:Nb on FTO crystals that are agglomerates of particles. Analysis of the current–voltage curves of the solar cells with Sb2S3 as the absorber material showed increased short-circuit current, fill factor and power conversion efficiency from 1.3 to 1.7%. The enhancement of the device performance is attributed to substitution of Ti ions with Nb ions in the TiO2 resulting in a change in the band alignment of the solar cells with Nb content. This results in increase in charge recombination resistance in the Sb2S3 layer as determined from the analysis of the impedance spectroscopy measurements.
  • Publication
    Publication
    Numerical Study of Copper Antimony Sulphide (CuSbS2) Solar Cell by SCAPS-1D
    (Heliyon, 2023-07-27) Obare, Nancy; Isoe, Wycliffe; Nalianya, Amos; Mageto, Maxwell; Odari, Victor
    Copper antimony sulphide has ability in applications on photovoltaics since it is a promising, less toxic, earth abundant absorber material. In this study, the photovoltaic characteristics of copper antimony sulphide (CuSbS2) photovoltaic cell were simulated and studied by one dimensional solar cell capacitance simulator (SCAPS-1D) to improve their operations. This study investigated the impact of modifying the thicknesses of fluorine-doped tin oxide (FTO), cadmium sulphide (CdS), carbon(C), and CuSbS2 absorber layer, Also the amount of doping and the number of defects on CuSbS2 photoactive layer, the structure of the solar cell is made up of glass, FTO, n-CdS, p-CuSbS2, C, and Au. The optimum parameters of the designed photovoltaic cell yielded 0.9388 V of open-circuit voltage (Voc), the short-circuit current density (Jsc) was 28.31 mA/cm2, the fill factor (FF) of 60.8%, and the solar cell efficiency of 16.17%. The ideal thickness was discovered to be 300 nm for the CuSbS2 solar cell. The defect density increment led to a decrease in carrier lifetime resulting also to decrease in diffusion length and the optimum absorber layer doping concentration was found to be 1018 cm-3
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    Publication
    Numerical study of lead free CsSn0.5Ge0.5I3 perovskite solar cell by SCAPS-1D
    (Elsevier, 2021-12) Nalianya, Milimo Amos; Awino, Celline; Barasa, Henry; Odari, Victor; Gaitho, Francis; Omogo, Benard; Mageto, Maxwell
    Lead free perovskite solar cells (PCS) are becoming a distinctly predominant area of study due to the toxicity and stability hurdles of the lead halide perovskite. Current lead-free perovskites are also plagued with low efficiency. This work is concerned with the design and analysis of CsSnGeI3 that is a viable competitor to lead based perovskites by SCAPS-1D simulator (ver.3.3.08). The primary solar cell’s structure is FTO/PCBM/ CsSn0.5Ge0.5I3 / spiro-OMeTAD/Au which achieved a power conversion efficiency (PCE) of 7.11% [1]. To enhance device performance, the effect of optimizing absorber layer defect density (1 × 1015 cm−3) and thickness (700–800 nm), doping concentration of absorber layer (1 × 1015 cm−3), variation of Electron Transport Material (ETL) and Hole Transport Material (HTL) parameters (effect of CBO and VBO and doping concentration) and potential material options for ETL and HTL are studied. The results of the simulation are as follows; maximum power conversion efficiency (PCE) 18.79%, short circuit current density (Jsc) 27.05 mA/cm2, open circuit voltage (Voc) 0.87 V and fill factor (FF) 79.25%. By choosing appropriate material parameters, improving fabrication and encapsulation processes, CsSn0.5Ge0.5I3 proves to be an environmentally friendly solar cell with high efficiency.
  • Publication
    Publication
    Thickness Dependence of Window Layer on CH3NH3PbI3-XClX Perovskite Solar Cell
    (International Journal of Photoenergy, 2020-07-28) Isoe, Wycliffe; Mageto, Maxwell; Maghanga, Christopher; Mwamburi, Maurice; Odari, Victor; Awino, Celline
    CH3NH3PbI3-xClx has been studied experimentally and has shown promising results for photovoltaic application. To enhance its performance, this study investigated the effect of varying thickness of FTO, TiO2, and CH3NH3PbI3-xClx for a perovskite solar cell with the structure glass/FTO/TiO2/CH3NH3PbI3-xClx/Spiro-OMeTAD/Ag studied using SCAPS-1D simulator software. The output parameters obtained from the literature for the device were 26.11 mA/cm2, 1.25 V, 69.89%, and 22.72% for Jsc, Voc, FF, and , respectively. The optimized solar cell had a thickness of 100 nm, 50 nm, and 300 nm for FTO, TiO2, and CH3NH3PbI3-xClx layers, respectively, and the device output were 25.79 mA/cm2, 1.45 V, 78.87%, and 29.56% for Jsc, Voc, FF, and , respectively, showing a remarkable increase in FF by 8.98% and 6.84% for solar cell efficiency. These results show the potential of fabricating an improved CH3NH3PbI3-xClx perovskite solar cell.