Browsing by Author "Attygalle, M.L.C."

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A numerical simulation of the effect of the surface defect layer (SDL) properties on 3D/2D perovskite solar cell performance
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Adihetty, N.L.; Ratnasinghe, D.R.; Attygalle, M.L.C.; Narayan, N.S.; Jha, P.K.
Organic-inorganic hybrid perovskites have become one of the promising solar cell materials in photovoltaic because of their low cost and excellent performance. In this study, we have modelled a hybrid organic-inorganic perovskite thin-film solar cell having p-i-n structure, with intrinsic layers of 3D methylammonium lead iodide (CH3NH3PbI3) (MAPI) and 2D monolayers of CH3NH3PbI3. The 2D layer is mainly used to improve the stability of the 3D CH3NH3PbI3 layer. The p-type layer is an organic hole transporting material (HTM) called Poly (3,4- ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The material fullerene derivative (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) is used as an organic electron transporting material (ETM) and this is the n-type layer. This numerical simulation study of a 3D/2D hybrid perovskite solar cell model has been carried out by using Solar Cell Capacitance Simulator (SCAPS-1D). In this study, we have intentionally included the surface defect layer (SDL), which is p-type, in between 3D-MAPI and 2D-MAPI layers to improve the performance of the 3D/2D perovskite-based thin-film solar cell model. The effect of the surface defect layer (SDL) is analyzed by changing the thickness, bandgap, and neutral defect density. According to the simulation results, the optimum thickness of SDL is in the range of 160-170 nm with the optimum SDL bandgap of 1.4 eV, has shown higher power conversion efficiency of the cell model. The neutral defect density of the SDL has been changed to identify the effect on the power conversion efficiency of the solar cell. We have also identified that the neutral defect density of the SDL should be kept less than 1013 cm-3 to get better performance. According to the results, we have observed the improvement of the solar cell efficiency of the cell structure, p-PEDOT:PSS/i-3DMAPI/p-SDL/i-2D-MAPI/n-PCBM/Ag, with the efficiency of 21.41%, open-circuit voltage (VOC) of 1.1034 V, short-circuit current density (JSC) of 25.59 mA/cm2 , and fill factor (FF) of 75.80%. This 3D/2D perovskite solar cell structure with SDL has shown good power conversion efficiency than that of the cell model that does not contain SDL, which is 19.65%. We have numerically simulated that the SDL can improve the efficiency and the performance of the cell model.
Parameter optimization of the II-VI thin-film photovoltaic tandem solar cell model of MZO/CdTe and CdS/CIGS
(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Ratnasinghe, D.R.; Attygalle, M.L.C.
In this simulation model we have constructed a photovoltaics tandem device with a top cell of window layer n-MZO (Mg doped ZnO), with an absorber layer of (II-VI) thin-film of p-CdTe and the bottom cell with window layer n-CdS and thin absorber layer of (II-VI) p-CIGS. Photovoltaic properties of CdTe/CIGS tandem solar cell have been studied by the Solar Cell Capacitance Simulator (SCAPS-1D) software. The thicknesses of n-CdS, p-CIGS, and the p-CdTe layers have been varied to improve the tandem solar cell device parameters such as open circuit voltage, short circuit current, fill-factor and the device efficiency. All the numerical simulations were conducted with one sun illumination condition with AM1.5G solar spectrum without any light trapping methods. In this simulation, we have observed 1. 37 V open circuit voltage, 24.5 mA/cm2 short circuit current, 85.9 fill factor and the highest efficiency value of 28.8493%. In this study we have presented a model of a tandem solar cell structure which can be used to enhance the performance of existing solar cells with the least material usage.
Performance investigation of Perovskite/CIGS tandem solar cell using numerical modelling and simulation
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Ratnasinghe, D.R.; Adihetty, N.L.; Attygalle, M.L.C.
In the modern world, multi-billion projects are going on researching photovoltaic (PV) devices. Considering the global energy demand the contribution of solar power is still negligible. Therefore, researchers are working on finding new solutions to enhance the performances of these PV devices. With the approach of the multi junctional PV devices, researchers identified a clear path to reach Shockley & Queisser’s detailed balanced limit. This research was focused on modelling a tandem cell structure with perovskite and CIGS materials to obtain the best efficient device with enhanced performance. Therefore, a two-terminal tandem structure was modelled computationally. The SCAPS-1D (one-dimensional solar cell capacitance simulator) software was used for the modelling and simulations. The top cell configuration was modelled with SnO2, PCBM, CH3NH3PbI3 and PEDOT: PSS materials and the bottom cell with ZnO, CdS and CIGS materials. The higher energy bandgap materials were used in the top cell to absorb the high energies from the AM1.5G spectrum. The energies penetrating through the top cell are absorbed by the bottom cell. Therefore, low energy bandgap materials were used for the bottom cell absorber. In the simulation procedure, a SCAPS script was used to analyze partial absorptions of the top cell. Additionally, a homojunction was created at the bottom cell CdS/CIGS interface according to previous studies. This process created an SDL (surface defect layer). The defect densities of the two interfaces; CdS/SDL and SDL/CIGS were altered to analyze the possible outcomes. According to the results, 30.946% efficiency was observed for the tandem device with 1.816 V open-circuit voltage and 20.863 mA/cm2 short circuit current. According to the defect density alteration of the interfaces, the defects at the SDL/CIGS interface showed high influence compared to CdS/SDL. With the results of JV characteristic curves and quantum efficiency curves, the current matching condition and the peak efficiency have appeared at the same condition. Therefore, the results adhere to the basic operation of the tandem configuration. By concerning the interface defect densities, it can be concluded that the changing defect densities at SDL/CIGS interface change the direction of the carriers, which causes the efficiency decrement. In numerical modelling, many assumptions were used, and the fabrication of the model is recommended to observe the practical situation.