Numerical Modeling of ZnxCd1-xS/ZnxCd1-xTe Solar Cell by AMPS-1D

Cogent Engineering

High efficiency ultrathin CdTe film is an excellent candidate for reliable, efficient, stable and low cost solar cells. In this paper, a high efficiency CdS/CdTe solar cell has been studied by using ADEPT 1D simulation tool. The proposed device has been simulated with a reduced CdTe absorber layer thickness and a ZnTe layer as back surface field (BSF) which substantiates sensible energy conversion efficiency. The investigation into the simulation results showed that the conversion efficiency with BSF layer and 1 μm thick CdTe absorber is 8.24% more as compared to the conventional CdTe cells (without BSF layer). Reduction of minority carrier recombination loss due to the insertion of BSF layer at the back contact in ultrathin CdS/CdTe cells has also been investigated. The results depict that CdTe cell with BSF layer is responsible for increasing the quantum efficiency. However, the proposed structure of ZnO/CdS/CdTe/ZnTe demonstrates the highest efficiency of 24.66% (V oc = 946.51 mV, J sc = 34.40 mA/cm 2 and FF = 75.72%) under global AM1.5G illumination spectra.

Journal of Materials Science: Materials in Electronics, 2023

Copper zinc tin sulfide solar cell (CZTS), Cu2ZnSnS4-based solar cells have shown promising conversion efficiency because of their ease of variation in configurations. In this work, the architecture of a ZnO–Al/i–ZnO/n–CdS/CZTS/Mo solar cell was optimized by using Silvaco Atlas simulation software. In this simulation study, the thickness and defect density of the CZTS layer has been varied to achieve the highest efficiency of 26.58%, with Isc = 36.64 A and Voc = 0.909 V at a defect density of 1.8 × 1012 cm−3. Increase in the layer thickness of CZTS improves the photon absorption and cell efficiency. This study has evidenced the impact of defect density on the absorber layer, including photo-generation rate, recombination rate, and solar cell efficiency. By optimizing the device parameters, it has achieved a fill factor of 79.74% under AM 1.5 illumination, demonstrating the potential for low-cost, highly efficient CZTS solar cells.

JOURNAL OF ADVANCES IN PHYSICS

A solar cell with glass/ITO/ZnS/Cu2ZnSnS4/CdTe/In structure has been fabricated using all-electrodeposited ZnS, Cu2ZnSnS4 and CdTe thin films. The three semiconductor layers were electrodeposited using a two-electrode system for process simplification. The incorporation of a wide bandgap amorphous ZnS as a buffer/window layer to form ITO/ZnS/Cu2ZnSnS4/CdTe/In solar cell resulted in the formation of this 3-layer device structure. This has yielded corresponding improvement in all the solar cell parameters resulting in a conversion efficiency >12% under AM1.5 illumination conditions at room temperature. These results demonstrate the advantages of the multi-layer device architecture over the conventional 2-layer structure.

Environmental Science and Pollution Research

The use of ZnTe as the buffer layer in the Cu 2 ZnSnS 4 (CZTS) based solar cells showed the improvement in overall e ciency. It may also reduce the overall cost of these cells as both the layers (absorbing and buffer) are having eco-friendly and earth abundant constitutes. The sol-gel spin coating method is used for the deposition of CZTS thin lms on the corning glass substrates. The X-ray diffraction studies showed the peaks corresponding to (112), (200), (220) and (312) planes which con rmed the formation of essential kesterite phase. The optical band gap of the deposited lms was found around 1.9 eV by UVvisible spectrophotometer. The optimum thickness of the absorber layer was investigated based on the performance of ZnO:Al/ZnO/ZnTe/CZTS/Mo cell structure by using AMPS-1D simulation tool, while the tool was moulded by the investigated data from the sol-gel deposited CZTS thin lms. The e ciency of solar cell was found to be increased till 22.64% with increment in the thickness of absorber buffer layer up to 2500 nm and beyond this it starts to decrease. In addition to this, it was also analysed that the current density is improved with operating temperature as it is one of the requirements in the high solar radiation areas where the temperature rise more than 50 C in summer.

Journal of Crystal Growth, 1982

Photovoltaic cells were prepared on oriented single-crystal substrates of Zn~Cdl_xS for compositions with 0 ~< x ~< 0.4. The copper sulphide layers were produced by dipping the substrates into a solution containing cuprous ions. The phases of these layers were determined using reflection electron diffraction. The open-circuit voltage under air mass one conditions of illumination increased with increasing zinc content, reaching a value of 0.72 V for x = 0.4. At the same time the short-circuit current density and the fill factor decreased, so that there was no improvement in efficiency over the CdS/Cu2S cell. Measurements of spectral response and of the effects of heat treatment at 200 °C are reported. These are interpreted to suggest that the thickness and the chalcocite content of the copper sulphide layers decreased as the zinc content of the substrates was increased.

Progress in Photovoltaics: Research and Applications, 2014

To improve CdS/CdTe cell/module efficiencies, CdS window layer thinning is commonly applied despite the risk of increased pin-hole defects and shunting. An alternative approach is to widen the band gap of the window layer (2.42 eV for CdS) via alloying, for example, by forming compositions of Cd 1Àx Zn x S. In this study, the performance of Cd 1Àx Zn x S/CdTe thin-film solar cells has been studied as a function of x (from x = 0 to 0.9), widening the window layer band gap up to and over 3.4 eV. Optimum Cd 1Àx Zn x S compositions were clearly identified to be around x = 0.7, and limitations to the achievable photocurrent and conversion efficiencies have been addressed.

Zinc Sulphide (ZnS) is a promising candidate to be an alternative buffer layer to the commonly used cadmium sulphide (CdS) in CZTS solar cells. In this study, buffer layer parameters like layer thickness and buffer layer bandgap have been investigated by Analysis of Microelectronic and Photonic Structures (AMPS-1D) to find out the higher conversion efficiency. A promising result has been achieved with an efficiency of 14.49% (with Voc = 0.81 V, Jsc = 28.85 mA/cm2 and Fill factor = 67.5) by using ZnS as a buffer layer. It is also found that the high efficiency of CZTS absorber layer thickness is between 2 µm and 4 µm. From the simulation results, it is revealed that higher efficiency can be achieved for the buffer layer bandgap around 3.10 eV - 3.25 eV. This result can be explained by the practical work as the bandgap of ZnS is largely dependent on the preparation conditions and stoichiometry. In conclusion, numerous influences of buffer layer are investigated in CZTS solar cell that can lead to the fabrication of high efficiency devices.

Biointerface Research in Applied Chemistry , 2023

Within the framework of the density functional theory (DFT) using the Wien2k package and the method of linear extended plane waves (FP-LAPW), quantum mechanical calculations were implemented to study the structural, electronic, and optical properties of the ZnxCd1-xTe system in the full range of 0≤x≤1 with a step of 0.25. To determine the optimal volume and grid parameters, the calculation of the total energy of semiconductor nanocomposites CdTe, Zn0.25Cd0.75Te, Zn0.5 Cd0.5 Te, Zn0.75Cd0.25Te, and ZnTe, the generalized gradient approximation (GGA) was applied, which is based on relaxation (optimization) of the volume and minimization of energy (finding the energy of the ground state). According to our calculations within the framework of the DFT, with an increase in the Zn concentration, the constant lattice parameters and the size (volume) of these nanocrystals decrease and are in good agreement with the results obtained this work by the method of X-ray structural analysis. The calculated band gaps of these nanocrystals using the modified exchange-correlation potential mBJ tend to increase, which agrees with the experimental data. The results of spin-polarized and spin-orbit calculations of the band structure showed that all these nanocrystals have direct transition points for electrons. After approximation by the least-squares method, empirical formulas were obtained to establish the concentration dependence of changes in the volumes and bandgap of Zn-modified nanocrystals, which will help experimenters obtain particles with certain sizes and bandgap. Such theoretical studies further open the possibility of accurate prediction of the electronic-energy properties of other semiconductor nanosized structur

2012

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2013

The main purpose of this paper is to investigate concerning the effect of bandgap, carrier concentration, minority carrier life time and thickness changes of the absorber layer in CdZnTe thin film solar cell baseline case. The band gap of − solar cellis tunable between 1.45eV and 2.2eV (depends on the value of x). In this research AMPS-1D has been used for simulation. The results of this study indicate that by decreasing of the absorber layer's thickness, the efficiency decreases. In the baseline cases, the absorber layer's bandgap was changed from 1.45eV to 2.05eV, It was found out that by increasing the energy gap, efficiency increase but after 1.85ev the bandgap will be constant, hence E g =1.88eV was considered for absorber to analyze the baseline cases. It was observed that by increasing the lifetime and carrier concentrations of absorber layer, the output parameters increase in the cells. However, proposed cell structure is Sn /CdS/CdZnTe/Ag and the highest conversion efficiency of 25.505% is obtained by baseline case 2 ( = 29.819 mA/ , = 1.28 Volt, FF= 0.731).