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Voc as a function of band gap energy and defect density
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In this study, Cu (In, Ga) Se2 (CIGS) material with the non-toxic titanium
dioxide TiO2 as an n-type buffer layer and indium tin oxide as the window
layer are numerically simulated using a solar cell capacitance simulation
software package. This numerical analysis has been carried out with the aim
of boosting the performances of CIGS/TiO2 solar cel...
Similar publications
In this work, the heterojunction composed of a n-type ZnO transparent conductive oxide (OTC) layer, a n-type CdS buffer layer and a absorber layer based Cu (In, Ga)Se2 p doped is studied under the influence of a KF layer placed in the CIGS/CdS interface. This study was done by varying the thickness of KF using thin-film simulation software named SC...
Citations
... State-of-the-art Cu (In, Ga)Se 2 (CIGS) based thin-film solar cells comprising a cadmium sulfide (CdS) buffer layer are regarded as one of the promising parts of solar cell technology to utilize abundant solar energy [1][2][3]. With a variable bandgap E g of 1.1-1.7 eV and an absorption coefficient ( α ) of 10 5 cm −1 , CIGS has already demonstrated tremendous success as a solar absorber material in the fabrication of environmentally stable and high-efficiency solar cells [4][5][6][7]. Additionally, compared to hydrogenated amorphous silicon (a-Si:H) and cadmium telluride (CdTe)-based thin-film solar cells (TFSCs), the construction of CIGS-based TFSCs is found to be relatively simple, economic, and eco-friendly [8][9][10]. ...
... So far, CdS is the most commonly used buffer layer in CdTe and CIGS solar cells [6,12,13]. Cadmium (Cd) has a bandgap of 2.4 eV, therefore absorbing photons in light wavelengths of 270-520 nm noticeably, but it is toxic and hazardous to the environment [14][15][16][17]. Regardless the toxicity, the efficacy of CdS has been investigated in detail and reported in previous study [11]. ...
The photovoltaic performance of copper indium gallium diselenide (CIGS)-based solar cells with Cd-free single buffer layers and a barium disulfide (BaSi 2) back-surface field (BSF) has been studied through a numerical approach using a one-dimensional solar cell capacitance simulator (SCAPS-1D). The efficacy of the buffer layer of cadmium sulfide (CdS) via FTO/CdS/CIGS/BaSi 2 /Mo heterostructure has been studied first and thereafter toxic CdS is replaced by various non-toxic buffers; zinc selenide (ZnSe), indium-doped zinc sulfide (ZnS:In), and indium sulfide (In 2 S 3). Comprehensive research has been performed on the effects of buffer layer thickness, gallium (Ga) concentration in CIGS absorber, BaSi2 BSF doping density, various back contact metals, and cell operating temperature. The highest power conversion efficiency (PCE) of the CIGS-based solar cell with the CdS buffer layer is 26.24 percent, while solar cells with Zn-based buffers made of ZnS:In or ZnSe show improved PCE of 17.68 percent and 17.56 percent, respectively. This study demonstrates the enormous potential of Zn-based ZnS:In and ZnSe buffers for the experimental fabrication of high-efficiency thin-film solar cells with the following structure: FTO/buffer/CIGS/BaSi 2 /Mo.
... The baseline parameters of CGS solar cell[19,[37][38][39][40] ...
The compound CuGaSe2 (CGS) is a potential wide bandgap semiconductor as a top cell for tandem solar cells in combination with a Cu(In,Ga)Se2 or Si bottom cell. However, the traditional cadmium sulfide (CdS) buffer layer usually forms a “cliff” structure at the heterojunction interface with CGS film, which deteriorates device performance of solar cell obviously. Herein, the non-toxic and wide bandgap TiO2 is studied as the n-type buffer layer of CGS thin film solar cell using SCAPS simulation software. First of all, the impact of different buffer layer thicknesses on the heterojunction interface is investigated systematically. It is found that the TiO2 buffer layer can reduce the conduction band offset (CBO) between the absorber layer and the buffer layer to about 0.03 eV, which can induce the photo-generated electrons across the interface barrier easily, and thus resulting an increase in device performance obviously. Further investigations on carrier concentrations of the buffer layer indicate high quality TiO2 buffer layer should have a lower carrier concentration below 2 × 10¹⁷ cm⁻³. This study offers a promising buffer layer material for CGS.
... Copper-indium-gallium-sulphurselenide (CIGSSe) and hexagonal ZnMgO are promising materials for making a good heterojunction thin-film solar cell (HTFSC). 16,17 The CIGSSe is a direct bandgap (I-III-VI) semiconductor compound that exhibits remarkable conversion efficiencies obtained by the co-evaporation method. 18 The CIGSSe materials have higher p-type conductivity, excellent stability, light weight, 14 less manufacturing cost ($0.34/W), ...
The performance of conventional magnesium-doped zinc oxide (ZnMgO) and copper-indium-gallium-sulphur-selenide (CIGSSe)-based heterojunction thin-film solar cells has been enhanced. The simulation of a conventional (Ni/Al)/ZnMgO:Al/ZnMgO/CIGSSe/Mo solar cell is done at the beginning of the paper to validate the simulation results with the experimental results. Electrical and optical parameter values obtained from the simulation are comparable to the results obtained from the experiment. Also, the efficiency of the conventional structure is increased to 26.53% by optimizing the thickness and doping concentration. A different structure is proposed that combines the copper-zinc-tin-gallium-diselenide (CZTGSe) p-type semiconductor at the back surface field (BSF) contact as a hole transport-electron reflected layer (HT-ERL). The efficiency of the proposed structure is enhanced by 7.63% compared to the recent contemporary literature and 1.10% compared to the optimized results. Moreover, the proposed structure comprises (Ni/Al)/ZnMgO:Al/ZnMgO/CIGSSe/CZTGSe/Mo, which provides the highest conversion efficiency of (η = 27.63%), an open-circuit voltage of (Voc= 807.3 mV), a short-circuit current density of (Jsc= 27.59 mA/cm2), and a fill factor of (FF = 82.26%), under the AM1.5G air mass.
... [7][8][9][10][11][12][13] TiO 2 has been tested as a candidate material for n-type buffer layers with promising results. [14][15][16][17][18] To be able to optimize the efficiency of such devices, the properties of TiO 2 films in an MIS structure must be clearly understood, which is currently not fully the case, even using a reference semiconductor material as a Si wafer. Previously published capacitance-voltage (C-V ) characterizations of TiO 2 MIS structures have shown unexpected behaviors: anomalous evolution of the maximum capacitance (C max ) with the TiO 2 thickness (t ox ) [19][20][21][22][23][24][25][26] or after air annealing 27) or a strong drop of the capacitance under strong reverse voltage. ...
This letter investigates the large spread of values of capacitance measured in Si/TiO 2 MIS structures for different properties of the TiO 2 layer and proposes an approach to understand the behavior of the system. Experimental results show large variations of the maximum capacitance with TiO 2 thickness for the as-deposited structures and further highlight the change of trend after annealing. Simulations qualitatively depict the theoretical trends explaining the C – V characteristics to the first order, by the different behaviors of the oxide layer in the structure and the distribution of the majority carriers showing depletion effects.
... Thus, suggesting that, TiO 2 shows the highest ղ among the other materials test and founded to be more suitable as a window layer with the investigated configuration. Moreover, TiO 2 found to be beneficial with CIGS solar cell and also helps in improving the stability of the cell [18,19]. ...
Reflection losses in solar cells lead towards thermalization losses which greatly affect the performance of the cell. This paper aims to report and explore a novel architecture to reduce the reflection losses by utilizing distributed braggs reflector (DBR) technique which is used to enhance the absorption of light in the active region. Theoretically, thickness optimization for different materials including Window, Buffer and Back Surface Field (BSF) was performed with different operating temperature with the objective to extract high performance parameters. After optimizing the materials for the effective layer, DBR pairs was introduced which delivers the highest efficiency (ղ) of 23.29% with the correlated parameters such as, Shot circuit current density, Jsc=27.83 mA/cm 2 , Open circuit voltage, Voc=1.02V and Fill factor, FF=87.76%. The results signify that the structure with BSF and DBR pairs shows enhanced performance parameters as compared to those structure without these layers. In addition, it has been observed that the increased number of DBR pairs result in the enhancement of ղ by 0.91% under 1.5 AM. The results strongly convinced that the introduction of DBR pairs significantly improves the performance parameters. Moreover, the optimized structure was tested with various operating J o u r n a l P r e-p r o o f temperature to examine its thermal stability towards high temperature. The proposed design with rigorously optimized layers can be a good choice for solar cell technology (STC) and can be employed as a substitute to less efficient solar cells.
... In addition, two very thin interface layers (IL) have been considered at the ETM/MAPbI3 and MAPbI3/HTM interfaces. Material parameters of various layers have been shown in table 1 [6][7][8][9][10][11][12][13]. The effective conduction band and valance band density of states are considered to be 2.2 × 10 18 cm −3 and 1.8 × 10 19 cm −3 , respectively [8]. ...
... It is also evident from Fig. 2 that α of FTO decreases in the wavelength range from 325 nm to 560 nm since the extinction coefficient of FTO decreases up to wavelength 560 nm. [39] [36] 6.5 6.5 [32] 6.5 100 [32] 9 Electron affinity χ/eV 4.1 [37] 3.91 3.91 [9] 3.91 4 [32] 4 Band gap E g /eV 1.49 [25] 1.56 1.56 [33] 1.56 3.26 [35] 3.5 Hole mobility µ p /cm 2 ·V −1 ·s −1 20 [37] 2 2 [34] 2 0.006 [32] 10 Electron mobility µ n /cm 2 ·V −1 ·s −1 25 [37] 3 3 [34] 3 0.006 [32] 20 ...
Organo-halide perovskites in planar heterojunction architecture have shown considerable promise as efficient light
harvesters in solar cells. We carry out a numerical modeling of a planar lead based perovskite solar cell (PSC) with
Cu2ZnSnS4 (CZTS) as the hole transporting material (HTM) using the one-dimensional solar cell capacitance simulator
(SCAPS-1D). The effects of numerous parameters such as defect density, thickness, and doping density of the absorber layer
on the device performance are investigated. The doping densities and electron affinities of the electron transporting material
(ETM) and the HTM are also varied to optimize the PSC performance. It has been observed that a thinner absorber layer of
220 nm with a defect density of 10^14 cm^-3 compared to the reference structure improves the device performance. When
doping density of the absorber layer increases beyond 2 x 10^16 cm^-3, the power conversion efficiency (PCE) reduces due
to enhanced recombination rate. The defect density at the absorber/ETM interface reduces the PCE as well. Considering a
series resistance of 5 Wcm^2 and all the optimum parameters of absorber, ETM and HTM layers simultaneously, the overall
PCE of the device increases significantly. In comparison with the reference structure, the PCE of the optimized device has
been increased from 12.76% to 22.7%, and hence the optimized CZTS based PSC is highly efficient.
... We used the solar cell capacitance simulator SCAPS-1D version 3.0.2 [47][48][49][50][51][52] which solves the semiconductor and electrostatic equation of transport and continuity equation using Newton-Ralphson-Gummel iteration. It performs 1D modeling of thin films polycrystalline solar cells like CIGS, CdTe, CZTS etc. ...
We employ simulation based approach for enhancing the efficiency of Cu2ZnSnS4 (CZTS) based solar cells. Initial benchmarking of simulation with the experimentally reported solar cell in literature is performed by incorporating a suitable defect model. We then explore the effects of (a) conduction band offset (CBO) at CZTS/CdS junction, (b) back surface field (BSF) due to an additional layer with higher carrier density, and (c) high work function back contact. Efficiency is observed to improve by about 70% upon optimizing the above three parameters. We also observe that utilizing BSF in the configuration can reduce the high work function requirement of the back contact. A work function of 5.2 eV (e.g., using Ni), a BSF layer (e.g., using SnS), and a CBO of 0.1 eV (e.g., using ZnS) constitute an optimal configuration.
... This is a one-dimensional simulation program, and it helps to analyze the spectral response (QE) of a device, J À V characteristics curve, ac characteristics (C À V and C À f), energy bands of materials used in solar cells, the concentration of different material used, open circuit voltage (V oc ), short circuit current (J sc ), fill factor (FF) and power conversion efficiency (PCE) by solving three basic semiconductor equations, i.e., Poisson's equation, and the hole and electron continuity equation. [26][27][28][29][30] The measure of a photovoltaic cell quality is the fill factor (FF). FF is premeditated by equating the maximum power (P max ) to the theoretical power (P t ) that would be output at both the short circuit current (J sc ) and open circuit voltage (V oc ) together as given in Eq. 1. The ratio of the energy output from the photovoltaic solar cell to the energy input from the sun is the power conversion efficiency (PCE) and mathematically expressed in Eq. 2. ...
Numerical analysis of the proposed solar cell is based on cadmium telluride (CdTe) and copper gallium sulfide (CuGaS2), also known as CGS, is proposed in this research work. Performance of a CdTe/CGS/CdS/ZnO cell is analyzed in Solar Cell Capacitance Simulator (SCAPS) software, by changing the physical parameters like doping density of acceptor, doping density of donor, absorber thickness and buffer thickness. The cell structure is in the same order as the CGS/CdS/ZnO with CdTe used for the back surface field layer. Power conversion efficiency of the CGS/CdS/ZnO solar cell without CdTe is 10.578% (with FF = 83.70%, Voc = 0.82 V, Jsc = 15.40 mA/cm²) and conversion efficiency of CdTe/CGS/CdS/ZnO is 28.20% (with FF = 77.66%, Voc = 1.22 V, Jsc = 29.63 mA/cm³). The overall investigation and simulation results from the modeling of a proposed device in SCAPS is very useful for the understanding of the fundamentals of photovoltaic devices and gives feedback to engineers and designers for the fabrication of CdTe/CGS based solar cells.
