Design and simulation of a high-performance Cd-free Cu2SnSe3 solar cells with SnS electron-blocking hole transport layer and TiO2 electron transport layer by SCAPS-1D

Performance analysis of un-doped and doped titania (TiO 2 ) as an electron transport layer (ETL) for perovskite solar cells

CONTEXT

Density functional theory (DFT) calculations are carried out on pure and doped rutile TiO2 . The bandgap (Eg ) for pristine, S-doped, Fe-doped, and Fe/S co-doped materials is direct, with values of 2.98 eV, 2.18 eV, 1.58 eV, and 1.40 eV. The effective mass of charge carriers (m*) and ratio of effective masses of holes to effective masses of electrons (R) are also investigated, and it is discovered that Fe/S co-doped materials have the lowest charge carrier recombination rate. The Fe/S co-doped material has the highest ε ( ω ) . α ( ω ) of doped materials shifted into the visible range. Due to the high dopant concentration in Fe and Fe/S-doped cases, the Eg is lowered to a relatively small value; hence, only pristine and S-doped materials are verified as electron transport layer (ETL). A solar cell device analysis employing pure and S-doped rutile TiO2 as ETL is completed using DFT-derived parameters in SCAPS-1D modeling software for the first time. For the optimized solar cells, current-voltage (IV) characteristics, quantum efficiency (QE), capacitance-voltage (CV) characteristics, and capacitance-frequency (Cf) characteristics are provided. The aim of the present study is to improve efficiency of perovskite solar cell by doping as well as to improve accuracy of simulation by applying DFT extracted parameters as input. From the analysis, improvement is found in efficiency of doped TiO2 compared to un-doped TiO2 . The efficiency of the PSC with S-doped ETL is 1.418% higher than the PSC with un-doped ETL.

METHOD

Quantumwise Automistic Tool Kit (ATK) is used to extract DFT parameters. Using these DFT parameters as input in SCAPS-1D (Solar Cell Capacitance Simulator), solar cells for doped and un-doped material are simulated. The density functional theory (DFT)-based orthogonalized linear combination of atomic orbital (OLCAO) technique is used. Structural optimization is done using the LBFGS (Limited-memory Broyden-Fletcher-Goldfarb-Shanno). PBESol-GGA (Perdew-Burke-Ernzerhof solid-generalized gradient approximation) is applied as exchange correlation for calculating structural parameters, while MGGA-TB09 (meta-generalized gradient approximation-Tran and Blaha) is applied as exchange correlation for calculating optical and electronic properties.

Performance simulation of the perovskite solar cells with Ti3C2 MXene in the SnO2 electron transport layer

MXenes, a class of two-dimensional (2D) transition metal carbides and nitrides, have a wide range of potential applications due to their unique electronic, optical, plasmonic, and other properties. SnO2-Ti3C2 MXene with different contents of Ti3C2 (0.5, 1.0, 2.0, 2.5 wt‰), experimentally, has been used as electron transport layers (ETLs) in Perovskite Solar Cells (PSCs). The SCAPS-1D simulation software could simulate a perovskite solar cell comprised of CH3NH3PbI3 absorber and SnO2 (or SnO2-Ti3C2) ETL. The simulation results like Power Conversion Efficiency (PCE), Open circuit voltage (VOC), Short circuit current density (JSC), Fill Factor (FF), and External Quantum Efficiency (EQE) have been compared within samples with different weight percentages of Ti3C2 MXene incorporated in ETL. Reportedly, the ETL of SnO2 with Ti3C2 (1.0 wt‰) effectively increases PCE from 17.32 to 18.32%. We simulate the role of MXene in changing the ideality factor (nid), photocurrent (JPh), built-in potential (Vbi), and recombination resistance (Rrec). The study of interface recombination currents and electric field shows that cells with 1.0 wt‰ of MXene in SnO2 ETL have higher values of ideality factor, built-in potential, and recombination resistance. The correlation between these values and cell performance allows one to conclude the best cell performance for the sample with 1.0 wt‰ of MXene in SnO2 ETL. With an optimization procedure for this cell, an efficiency of 27.81% is reachable.

Comprehensive analysis of heterojunction compatibility of various perovskite solar cells with promising charge transport materials

The allure of perovskite solar cells (PSCs), which has captivated the interest of researchers, lies in their versatility to incorporate a wide range of materials within the cell's structure. The compatibility of these materials plays a vital role in the performance enhancement of the PSC. In this study, multiple perovskite materials including FAPbI3, MAGeI3 and MASnI3 are numerically modelled along with the recently emerged kesterite (CBTS, CMTS, and CZTS) and zinc-based (ZnO and CdZnS) charge transport materials. To fully explore the potential of PSCs and comprehend the interplay among these materials, a total of 18 PSC structures are modeled from different material combinations. The impact of band gap, electron affinity, absorption, band alignment, band offset, electric field, recombination rate, thickness, defects, and work function were analyzed in detail through a systematic approach. The reasons for varying performance of different PSCs are also identified. Based on the simulated results, the most suitable charge transport materials are CdZnS/CMTS for FAPbI3 producing a power conversion efficiency (PCE) of 22.05%, ZnO/CZTS for MAGeI3 with PCE of 17.28% and ZnO/CBTS for MASnI3 with a PCE of 24.17%.

Performance analysis of n-TiO2/p-Cu2O, n-TiO2/p-WS2/p-Cu2O, and n-TiO2/p-WS2 heterojunction solar cells through numerical modelling

A new hetero-structure of n-TiO2/p-WS2/p-Cu2O is proposed as a potential candidate for solar energy generation using tungsten disulfide (WS2) as an absorber layer. The proposed device performance is simulated by employing a one-dimensional solar cell capacitance simulator (SCAPS-1D). The numerical simulation studies compared the performances of n-TiO2/p-Cu2O, n-TiO2/p-WS2/p-Cu2O, and n-TiO2/p-WS2 hetero-structures based on various physical parameters like interface defects density, bulk defects density, absorber layer thickness, series resistance, shunt resistance, and operating temperature. In our simulation investigations, we found that interface defects pose a formidable impact on heterojunction devices. Interface defects closer to the front surface severely deteriorate the performances than the back surface. The bandgap of the absorber layer influences the performances of the solar cells. A closer comparison between n-TiO2/p-Cu2O and n-TiO2/p-WS2 heterojunction solar cells (HJSCs) revealed that the latter (n-TiO2/p-WS2) has nearly 182% better performance than the former (n-TiO2/p-Cu2O) devices. Additionally, the performance of the n-TiO2/p-WS2 solar cell is further boosted by ~ 139% in the presence of a hole transport layer of p-Cu2O. The best-simulated efficiency of the proposed new hetero-structure (n-TiO2/p-WS2/p-Cu2O) solar cell is 28.86%. Moreover, these optimized physical parameters may shed light on "easy to apply" new path for fabrication of a non-toxic, environment-friendly, and highly efficient novel thin-film heterojunction (n-TiO2/p-WS2/p-Cu2O) solar cell.

High efficiency Cu2MnSnS4 thin film solar cells with SnS BSF and CdS ETL layers: A numerical simulation

The quaternary compound copper manganese tin sulfide Cu₂MnSnS₄ is a potential absorber semiconductor material for fabricating thin film solar cells (TFSC) thanks to their promising optoelectronic parameters. This article numerically investigated the performance of Cu₂MnSnS₄ (CMTS)-based TFSC without and with tin sulphide (SnS) back surface field (BSF) thin-film layer. First, the impact of several major influential parameters such as the active material's thickness, doping concentration of photoactive materials, density of bulk and interface defect, working temperature, and metal contact, were studied systematically without a BSF layer. Thereafter, the photovoltaic performance of the optimized pristine cell was further investigated with an SnS as BSF inserted between the absorber (CMTS) with a Platinum back metal of an optimized heterostructure of Cu/ZnO:Al/i-ZnO/n-CdS/p-Cu₂MnSnS₄/Pt. Thus, the photoconversion efficiency (PCE) of 25.43% with a J _SC of 34.41nullmA/cm² and V _OC of 0.883 V was achieved under AM1.5G solar spectrum without SnS BSF layer. Furthermore, an improved PCE of 31.4% with a J _SC of 36.21nullmA/cm² and V _OC of 1.07 V was achieved with a quantum efficiency of over 85% in the wavelengths of 450-1000 nm by the addition of SnS BSF layer. Thus, this obtained systematic and consistent outcomes reveal immense potential of CMTS with SnS as absorber and BSF, respectively and provide imperious guidance for fabricating highly a massive potential efficient solar cell.

Performance simulation of solar cell based on AZO/CdTe heterostructure by SCAPS 1D software

Simulation and analysis of solar cells based on the heterojunction of zinc oxide doped with aluminum (AZO) and cadmium telluride (CdTe) with the structure (Al/AZO/CdTe/NiO/Ni) using the Simulator of the capacitance of solar cells - 1 dimension (SCAPS-1D) has been presented in this paper. AZO is used as a window layer and Nickel oxide (NiO) has been introduced as a hole transport layer (HTL). Through the software, the effect of thickness, absorber (CdTe), and window (AZO) layers carrier concentration, operating temperature, and resistances (series and shunt) have been studied. Simulation results show that the solar cell performance can be greatly improved by adjusting the layer's thickness and carrier concentration, obtaining optimal values of 10 nm and 10 18 c m - 3 for the AZO layer, while for the CdTe layer they were 2 μm and 10 15 c m - 3 . The optimum series and shunt resistances are in the range of 1-3 Ω c m 2 and 1800-2200 Ω c m 2 respectively. A maximum power conversion efficiency (PCE) of 14.2% is achieved with an open circuit voltage (Voc) of 0.74 V, short circuit current density (Jsc) of 26.15 m A / c m 2 and a fill factor (FF) of 72.83%, this shows AZO potential to be considered as an interesting material to replace CdS window layer.

Touhidul Islam AZ. Performance Enhancement of an MoS2-Based Heterojunction Solar Cell with an In2Te3 Back Surface Field: A Numerical Simulation Approach

Researchers are currently showing interest in molybdenum disulfide (MoS₂)-based solar cells due to their remarkable semiconducting characteristics. The incompatibility of the band structures at the BSF/absorber and absorber/buffer interfaces, as well as carrier recombination at the rear and front metal contacts, prevents the expected result from being achieved. The main purpose of this work is to enhance the performance of the newly proposed Al/ITO/TiO₂/MoS₂/In₂Te₃/Ni solar cell and investigate the impacts of the In₂Te₃ BSF and TiO₂ buffer layer on the performance parameters of open-circuit voltage (V _OC), short-circuit current density (J _SC), fill factor (FF), and power conversion efficiency (PCE). This research has been performed by utilizing SCAPS simulation software. The performance parameters such as variation of thickness, carrier concentration, the bulk defect concentration of each layer, interface defect, operating temperature, capacitance-voltage (C-V), surface recombination velocity, and front as well as rear electrodes have been analyzed to achieve a better performance. This device performs exceptionally well at lower carrier concentrations (1 × 10¹⁶ cm^-3) in a thin (800 nm) MoS₂ absorber layer. The PCE, V _OC, J _SC, and FF values of the Al/ITO/TiO₂/MoS₂/Ni reference cell have been estimated to be 22.30%, 0.793 V, 30.89 mA/cm², and 80.62% respectively, while the PCE, V _OC, J _SC, and FF values have been determined to be 33.32%, 1.084 V, 37.22 mA/cm², and 82.58% for the Al/ITO/TiO₂/MoS₂/In₂Te₃/Ni proposed solar cell by introducing In₂Te₃ between the absorber (MoS₂) and the rear electrode (Ni). The proposed research may give an insight and a feasible way to realize a cost-effective MoS₂-based thin-film solar cell.

Optimization of Photovoltaic Performance of Pb-Free Perovskite Solar Cells via Numerical Simulation

Recently, the simulation of perovskite solar cells (PSCs) via SCAPS-1D has been widely reported. In this study, we adopted SCAPS-1D as a simulation tool for the numerical simulation of lead-free (Pb-free) PSCs. We used methyl ammonium germanium iodide (MAGeI₃) as a light absorber, zinc oxysulphide (ZnOS) as an electron transport layer (ETL), and spiro-OMeTAD as a hole transport layer. Further, the thickness of the ZnOS, MAGeI₃, and spiro-OMeTAD layers was optimized. The optimal thicknesses of the ZnOS, MAGeI₃, and spiro-OMeTAD layers were found to be 100 nm, 550 nm, and 100 nm, respectively. The optimized MAGeI₃-based PSCs exhibited excellent power conversion efficiency (PCE) of 21.62%, fill factor (FF) of 84.05%, and Jsc of 14.51 mA/cm². A fantastic open circuit voltage of 1.77 V was also obtained using SCAPS-1D. We believe that these theoretically optimized parameters and conditions may help improve the experimental efficiency of MAGeI₃-based PSCs in the future.

Numerical Simulation of NH3(CH2)2NH3MnCl4 Based Pb-Free Perovskite Solar Cells Via SCAPS-1D

Recently, the design and fabrication of lead (Pb)-free perovskite or perovskite-like materials have received great interest for the development of perovskite solar cells (PSCs). Manganese (Mn) is a less toxic element, which may be an alternative to Pb. In this work, we explored the role of NH₃(CH₂)₂NH₃MnCl₄ perovskite as a light absorber layer via SCAPS-1D. A Pb-free PSC device (FTO/TiO₂/NH₃(CH₂)₂NH₃MnCl₄/spiro-OMeTAD/Au) was simulated via SCAPS-1D software. The simulated Pb-free PSCs (FTO/TiO₂/NH₃(CH₂)₂NH₃MnCl₄/spiro-OMeTAD/Au) showed decent power conversion efficiency (PCE) of 20.19%. Further, the impact of the thickness of absorber (NH₃(CH₂)₂NH₃MnCl₄), electron transport (TiO₂), and hole-transport (spiro-OMeTAD) layers were also investigated. Subsequently, various electron transport layers (ETLs) were also introduced to investigate the role of ETL. In further studies, an NH₃(CH₂)₂NH₃MnCl₄-based PSC device (FTO/TiO₂/NH₃(CH₂)₂NH₃MnCl₄/spiro-OMeTAD/Au) was also developed (humidity = ~30-40%). The fabricated PSCs displayed an open circuit voltage (Voc) of 510 mV with a PCE of 0.12%.

Machine Learning Approach to Delineate the Impact of Material Properties on Solar Cell Device Physics

In this research, solar cell capacitance simulator-one-dimensional (SCAPS-1D) software was used to build and probe nontoxic Cs-based perovskite solar devices and investigate modulations of key material parameters on ultimate power conversion efficiency (PCE). The input material parameters of the absorber Cs-perovskite layer were incrementally changed, and with the various resulting combinations, 63,500 unique devices were formed and probed to produce device PCE. Versatile and well-established machine learning algorithms were thereafter utilized to train, test, and evaluate the output dataset with a focused goal to delineate and rank the input material parameters for their impact on ultimate device performance and PCE. The most impactful parameters were then tuned to showcase unique ranges that would ultimately lead to higher device PCE values. As a validation step, the predicted results were confirmed against SCAPS simulated results as well, highlighting high accuracy and low error metrics. Further optimization of intrinsic material parameters was conducted through modulation of absorber layer thickness, back contact metal, and bulk defect concentration, resulting in an improvement in the PCE of the device from 13.29 to 16.68%. Overall, the results from this investigation provide much-needed insight and guidance for researchers at large, and experimentalists in particular, toward fabricating commercially viable nontoxic inorganic perovskite alternatives for the burgeoning solar industry.

Performance analysis of WSe2-based bifacial solar cells with different electron transport and hole transport materials by SCAPS-1D

In recent years, solar cells made of tungsten diselenide (WSe₂) have received comprehensive consideration because of their good photoelectric properties. The planar WSe₂-based heterojunction solar cell with a preliminary device structure of Au/WSe₂/electron transport layer (ETL)/FTO/Al was designed and investigated numerically by SCAPS-1D. CdS ETL is widely used in thin film solar cells (TFSCs). Due to environmental issues and the low band gap (2.42 eV) of CdS ETL, an alternative to CdS ETL was being explored for WSe₂ solar cells. In this work, the photovoltaic (PV) performance of the WSe₂-based TFSCs with different ETLs were simulated, analyzed and compared, in an attempt to track down a suitable substitute for the CdS ETL. In addition to CdS ETL, ZnO, TiO₂ and SnO₂ ETLs were independently used to simulate the PV performance of WSe₂-based TCSCs. In the wake of analyzing the J-V curves of different cell configurations, SnO₂ ETL yielded the best results with PCE of 27.14 % for the single-junction WSe₂/SnO₂ TFSC. Then, our simulation predicted that the PV performance of the WSe₂ device can be improved significantly by using N doped Cu₂O as a hole transport layer (HTL). The optimized WSe₂ device with SnO₂ ETL and Cu₂O:N HTL showed an improved PCE of 33.84 % with very good performance stability at higher temperature. Furthermore, this article proposes to use the Au/Cu₂O:N/WSe₂/SnO₂/FTO/Al heterojunction solar cell in bifacial mode and PV performance of the proposed bifacial device have been also studied using SCAPS-1D. Bifacial WSe₂ device leads to enhanced PV performance with bifaciality factor for PCE is 83.64 %. Bifacial gain of the proposed device under simultaneous irradiation of 1 sun from the front and 20 % of 1 sun from back side is found to be 13.95 %. Our simulation predicts that the proposed WSe₂ bifacial solar cell is capable of converting solar energy into electricity with an efficiency of about 38.38 %.

Simulating the performance of a highly efficient CuBi2O4-based thin-film solar cell

In this study, copper bismuth oxide (CuBi2O4) absorber-based thin film heterojunction solar cell structure consisting of Al/FTO/CdS/CuBi2O4/Ni has been proposed. The proposed solar cell device structure has been modeled and analyzed by using the solar cell capacitance simulator in one dimension (SCAPS-1D) software program. The performance of the proposed photovoltaic device is evaluated numerically by varying thickness, doping concentrations, defect density, operating temperature, back metal contact work function, series and shunt resistances. The current density–voltage behaviors at dark and under illumination are investigated. To realize the high efficiency CuBi2O4-based solar cell, the thickness, acceptor and donor densities, defect densities of different layers have been optimized. The present work reveals that the power conversion efficiency can be enhanced by increasing the absorber layer thickness. The efficiency of 26.0% with open-circuit voltage of 0.97 V, short-circuit current density of 31.61 mA/cm2, and fill-factor of 84.58% is achieved for the proposed solar cell at the optimum 2.0-μm-thick CuBi2O4 absorber layer. It is suggested that the p-type CuBi2O4 material proposed in the present study can be employed as a promising absorber layer for applications in the low cost and high efficiency thin-film solar cells.