Influence of bulk defects in SnS absorber layer on optical and electrical properties of solar cell

In this research, the effect of bulk defect on the performance of the solar cell was studied by using the AFORS-HET simulation program. This was done by varying the density of defects including both Acceptor-like and donor-like within the SnS absorption layer. The thickness of the SnS layer was changed from 600nm to 9000nm with the change in bulk defect density in the same layer from (1E10 to 1E17 cm−3). The results showed that when the density of defects is less than 1E14cm−3, it has no effect on the performance of the solar cell, but its effect appears after this concentration, On the contrary, it is the effect of thickness, the results showed that the change in thickness at the defect density of E16cm−3 does not affect on the optical and electrical properties. Also, the results showed that the effect of defects is greatest at low concentrations of Na impurities, and this effect begins to decrease with increasing the concentration of impurities.

Simulation and Numerical Modelling of CIGSSe-Based Solar Cells by AFORS-HET

A general equation to determine properties of penternary solar cell based on Cu (In, Ga) (Se, S) 2 (CIGSSe) with a double buffer layer ZnS/Zn0.8Mg0.2O(ZMO) were derived. Numerical analysis of a (CIGSSe) solar cell with a double buffer layer ZnS/ZMO, CdS free absorber layer, were investigated using the AFORS-HET software simulation. Taking into consideration the effect of thickness and doping concentration for the CIGSSe absorption layer, ZnS buffer layer and ZnO:B(BZO) window layer on the electron transport, short circuit current density (Jsc) and open circuit voltage (Voc); numerical simulation demonstrated that the changes in band structure characteristics occurred. The solar energy conversion efficiency is 28.34%, the filling factor is 85.59%, the open circuit voltage is 782.3 mV, the short circuit current is 42.32 mA. then we take the range of the gradient between the ratio of x and y for the absorption layer, and the best result of Voc, Jsc, FF, Eff equal (838.7 mV, 40.94 mA/cm2, 86.23%, 29.61%) respectively at x= 0, y= 0.26.

Simulation of Extended Wavelength Avalanche Photodiode with the Type-II Superlattice Absorption Layer

The relationship between the performance of avalanche photodiode (APD) and structural parameters of the absorption, grading, and multiplication layers has been thoroughly simulated and discussed using the equivalent materials approach and Crosslight software. Based on separate absorption, grading, charge, and multiplication (SAGCM) structure, the absorption layer of APD was replaced with InGaAs/GaAsSb superlattice compared to conventional InGaAs/InP SAGCM APD. The results indicated that the breakdown voltage increased with the doping concentration of the absorption layer. When the thickness of the multiplication layer increased from 0.1 μm to 0.6 μm, the linear range of punchthrough­­­ voltage increased from 16 V to 48 V, and the breakdown voltage decreased at first and then increased when the multiplication layer reached the critical thickness at 0.35 μm. The grading layer could not only slow down the hole carrier, but also adjust the electric field. The dark current was reduced to about 10 nA and the gain was over 100 when the APD was cooled to 240 K. The response wavelength APD could be extended to 2.8 μm by fine tuning the superlattice parameters. The simulation results indicated that the APD using superlattice materials has potential to achieve a long wavelength response, a high gain, and a low dark current.

Analysis on the Seismic Performance of Shock Absorption Layer Applied in Tunnel Lining Structure Using Shaking Table Model Tests

Shock absorption layer is a relatively simple and effective aseismic measure, which can bear the adverse effects of surrounding rock deformations and buffer the forces acting on lining structure with seismic action. This paper conducts a series of shaking table model tests to analyze and compare the aseismic performances of tunnel lining structure with and without shock absorption layer in different grades of surrounding rocks, in which the superior thickness of shock absorption layer is determined. Therein, it is concluded that the shock absorption layer has prominent influence on reducing the acceleration responses of surrounding rock and lining structure with seismic excitation. The setting of the shock absorption layer can reduce the acceleration amplitude of tunnel lining with seismic excitation by about half. Furthermore, the setting of 1 cm shock absorption layer will increase the Fourier amplitudes and change the vibration frequencies of surrounding rock and lining structure with seismic excitation, while the setting of 2 cm shock absorption layer can significantly decrease the Fourier amplitudes and keep the vibration frequencies of surrounding rock and lining structure with seismic excitation. Therefore, the aseismic effect of 2 cm shock absorption layer is better than the aseismic effect of 1 cm shock absorption layer, which can both reduce the acceleration amplitude and Fourier amplitude of tunnel lining with seismic excitation while keep its characteristics in frequency domain. This research on the aseismic performance of shock absorption layer can contribute to the construction of tunnel engineering and improve the safety of tunnel lining structure.

Improving the Performance of Organic Lead-tin Laminated Perovskite Solar Cells From the Perspective of Device Simulation

The toxic lead in traditional perovskite solar cells (PSCs) poses a fatal threat to the environment, and it takes time and technology to complete the transition to lead-free perovskite solar cells. In this work, we introduce a lead-tin laminated perovskite solar cell, which can obviously reduce the toxicity of lead. Our ultimate goal is to study the factors that affect the performance of the device. On the basis of reducing the lead-based perovskite layer, use SACPS-1D (solar cell capacitor simulator) to optimize the parameters to maximize the performance of the entire device. Adjusting the physical parameters, we got the power conversion efficiency (PCE) of 17.59% and 6.14% for single-cell lead-based and single-cell tin-based perovskite solar cells respectively, which are close to the experimental results. The simulation results show that under the laminated structure, the thickness of the two perovskite absorber materials based on lead and tin has a certain influence on the performance of the device. After optimization, it is determined that the best thicknesses of lead-based absorption layer (LBA) and tin-based absorption layer (TBA) are 20nm and 150nm respectively. Optimize the doping concentration of acceptor and donor of the laminated perovskite absorber layer to obtain higher PCE and open circuit voltage (VOC). The best values are 1015cm-3 and 1016cm-3 for LBA and TBA respectively. We also found that when adjusting the positions of LBA and TBA, the recombination rate under different defect densities verified that the laminated absorption layer close to the light source side dominates the device performance. Provide reference for future optimization of laminated perovskite solar cells. Considering these factors comprehensively, we optimized the device performance parameters as follows: VOC=0.9266V, JSC =19.5556 mA/cm2, FF=71.12 % and PCE=12.89%.

Rational Design and Simulation of Two-Dimensional Perovskite Photonic Crystal Absorption Layers Enabling Improved Light Absorption Efficiency for Solar Cells

A two-dimensional perovskite photonic crystal structure of Methylamine lead iodide (CH3NH3PbI3, MAPbI3) is rationally designed as the absorption layer for solar cells. The photonic crystal (PC) structure possesses the distinct “slow light” and band gap effect, leading to the increased absorption efficiency of the absorption layer, and thus the increased photoelectric conversion efficiency of the battery. Simulation results indicate that the best absorption efficiency can be achieved when the scattering element of indium arsenide (InAs) cylinder is arranged in the absorption layer in the form of tetragonal lattice with the height of 0.6 μm, the diameter of 0.24 μm, and the lattice constant of 0.4 μm. In the wide wavelength range of 400–1200 nm, the absorption efficiency can be reached up to 82.5%, which is 70.1% higher than that of the absorption layer without the photonic crystal structure. In addition, the absorption layer with photonic crystal structure has good adaptability to the incident light angle, presenting the stable absorption efficiency of 80% in the wide incident range of 0–80°. The results demonstrate that the absorption layer with photonic crystal structure can realize the wide spectrum, wide angle, and high absorption of incident light, resulting in the increased utilization efficiency of solar energy.