Lead-free Perovskite Materials Research Articles

Hardware-based security devices using a physical unclonable function created by the irregular grain boundaries found in perovskite calcium titanate

The IoT era necessitated the need for hardware-based security devices due to their strong resistance to hacking compared to software-based systems, which are limited by CPU usage and performance. Hardware-based systems are more unpredictable due to their unique and non-discernible external properties. This research focused on developing a security device based on lead-free metal oxide CaTiO3 perovskite material with irregular electrical characteristics, known as physical unclonable functions. These irregularities were created by increasing the number of grain boundaries on the device surface through high-temperature annealing, resulting in greater adsorbed oxygen. The outcome was a highly random and unique security key using irregular electrical characteristics with 49.53% uniformity and a 46.55% inter-Hamming distance.

Achieving superb electric energy storage in relaxor ferroelectric BiFeO3-BaTiO3-NaNbO3 ceramics via O2 atmosphere

Lead-free perovskite dielectric materials for storing electrical energy have been widely investigated due to their high polarization and reversible phase. However, their low electric resistivity limits the energy density and stability. In this study, the (1-x)(0.7BiFeO3-0.3BaTiO3)-xNaNbO3 ceramics (x = 0 – 0.2) were prepared using two sintering atmospheres (air and oxygen). A superb recoverable energy-stored density (Wrec) of 8.2 J/cm3 and efficiency (η) of 70% was achieved at x = 0.15 sintered in O2 atmosphere. The superior Wrec is due to the structural coexistence of ferroelectric rhombohedral (R3c), nonpolar cubic (Pm-3m), and antiferroelectric orthorhombic (Pbam) symmetries, tailored via antiferroelectric NaNbO3 addition. The improved breakdown strengths (up to 325 kV/cm) are due to the increased interatomic bonding linked to the BO6 octahedron and lattice network. Altogether, NaNbO3-substitution and O2 sintering synergistically resulted in excellent energy storage and pave a scheme of antiferroelectric-tailoring BiFeO3-BaTiO3–NaNbO3 relaxor ferroelectrics for dielectric capacitor.

First-principles investigation of stable lead-free halide perovskite materials CsSnCl x Br y I3−x−y for solar cell applications

Perovskite solar cells based on hybrid organic–inorganic lead halide materials have attracted immense interest in recent years due to their enhanced power conversion efficiency. However, the toxic lead element and unstable property of the material limit their applications. With first-principles calculations based on density functional theory, we studied a series of ten lead-free perovskite materials made of cesium, tin, and halogen elements, chlorine (Cl), bromine (Br), and iodine (I). We found that the relative concentrations of the halogen atoms determine the crystal structures and the relative stability of the halide perovskites. Chlorine tends to increase the structural stability, while iodine plays the role of reducing the band gaps of the mixed halide perovskites. Considering the stability and the requirement of suitable band gaps, we identify that, among the ten lead-free halide perovskites, CsSnCl2I, CsSnBr2I, CsSnClBrI, CsSnClI2, CsSnBrI2, and CsSnI3 are the appropriate choices for solar cell applications.

Improvement in conductivity of lead-free CH3NH3SnI3 perovskite thin film using multi-walled carbon nanotubes as a transporter

CH3NH3SnI3 is a lead-free perovskite material that gains significant attention due to its favourable properties for optoelectronic device applications. It is a potential replacement for lead-based perovskite materials. However, the presence of traps, defects, and oxidation vacancies within these perovskite-based devices hinders the flow of charge carriers, causing them to become trapped or recombined within the device before reaching the electrodes. This limits the electrical performance of the device. To address this issue, this study focuses on improving the electrical performance of CH3NH3SnI3 perovskite by incorporating MWCNTs. Thin films of CH3NH3SnI3 perovskite were prepared both with and without MWCNTs. By employing the Van der Pauw method, resistivity measurements revealed that the electrical conductivity of the film increased to 7.80 × 10−2 S/m with the presence of MWCNTs, compared to 8.4 × 10−4 S/m without them. I-V measurements of the thin films-based Schottky devices showed that the conductivity increased from 1.21 × 10−5 S/m to 1.02 × 10−4 S/m with MWCNTs, while the barrier height decreased from 0.51 eV to 0.43 eV, and the ideality factor decreased from 4.01 to 2.56. The improved electrical performance observed when MWCNTs were incorporated, suggested that they formed a charge transfer pathway for carriers within the perovskite material. This pathway reduced trap energy, enabling charge carriers to percolate between grains and reach the electrodes. These findings highlight the significance of MWCNTs as a means to enhance the charge transfer dynamics in environmentally friendly CH3NH3SnI3 perovskite-based devices. Such improvements have promising implications for the development of future perovskite-based devices.

Molecular Tailoring of Pyridine Core-Based Hole Selective Layer for Lead Free Double Perovskite Solar Cells Fabrication.

To solve the toxicity issues related to lead-based halide perovskite solar cells, the lead-free double halide perovskite Cs2AgBiBr6 is proposed. However, reduced rate of charge transfer in double perovskites affects optoelectronic performance. We designed a series of pyridine-based small molecules with four different arms attached to the pyridine core as hole-selective materials by using interface engineering. We quantified how arm modulation affects the structure-property-device performance relationship. Electrical, structural, and spectroscopic investigations show that the N3,N3,N6,N6-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine arm's robust association with the pyridine core results in an efficient hole extraction for PyDAnCBZ due to higher spin density close to the pyridine core. The solar cells fabricated using Cs2AgBiBr6 as a light harvester and PyDAnCBZ as the hole selective layer measured an unprecedented 2.9% power conversion efficiency. Our computed road map suggests achieving ∼5% efficiency through fine-tuning of Cs2AgBiBr6. Our findings reveal the principles for designing small molecules for electro-optical applications as well as a synergistic route to develop inorganic lead-free perovskite materials for solar applications.

SCAPS device simulation study of formamidinium Tin-Based perovskite solar Cells: Investigating the influence of absorber parameters and transport layers on device performance

The use of tin-based perovskite has gained popularity as an alternative to toxic lead-based perovskite in solar cells. Despite the wider absorption of the lead-free perovskite material known as CH3NH3SnI3, it is prone to temperature instability, which limits its applicability. Compared to CH3NH3SnI3, the absorber comprising FASnI3 (HC(NH2)2SnI3) exhibits greater temperature stability and a wider band gap of 1.41 eV. This study employs SCAPS to simulate FASnI3-based solar cells, examining how altering the absorber parameters, including thickness, doping concentration, and defect density, affects device performance. Additionally, we investigate the influence of modifying the conduction band offset (CBO) and valence band offset (VBO), as well as the thickness and doping concentration of the electron and hole transport layers (ETL and HTL). Furthermore, the impact of interface defect density, series and shunt resistance, and the temperature dependency of the device performance are analyzed. The original design was founded on an experiment that achieved a PCE of 1.75%. However, the presented parametric study led to improvements in the intended solar cell's performance parameters. Specifically, the cell's short-circuit current density (JSC) increased to 26.9 mA/cm2, the fill factor (FF) reached 74.22 %, the open-circuit voltage (VOC) rose to 0.907 V, and the power conversion efficiency (PCE) reached 18.11% at room temperature. Additionally, at a lower temperature of 280 K, the PCE further increased to 19.19%. The findings provide valuable insights into the efficiency, stability, and optimization of FASnI3-based solar cells for renewable energy applications.

Performance evaluation and the optimization of an inverted photo-voltaic cell with lead-free double perovskite material and inorganic transport layer materials

The research on the solar cell structure based on various inorganic, organic and hybrid type of perovskite absorbing materials is increasing due to their legion features. Various inorganic titanium (Ti) based double perovskite absorbing materials like, Cs2TiCl6, Cs2TiBr6, and Cs2TiI6 are examined. Cs2TiBr6 is chosen to be the most promising absorbing layer material alternative suitable for a stable environmentally friendly solar cell application due to its larger spectrum response and tunable band gap than the other promising absorbing materials. The primary objective of this work aims for investigating the functioning of Cs2TiBr6 with various inorganic charge transport materials under simulated conditions using the simulation software, SCAPS-1D (a Solar Cell Capacitance Simulator), Solar Cell Capacitance Simulator, and its functioning is evaluated by varying the interface defect density, thickness, defect density, etc. of various layer materials of the solar cell device. The basic input parameters, like electron-affinity, thickness, band-gap, charge mobility, permittivity, and defect density, of different layer materials are used in the simulation software to accomplish the modelling of the novel structure of solar cell device. A highly efficient environmentally friendly perovskite solar cell structure is the focus of this numerical research. Analysis results are compared with the existing data for substantiation. Finally, one planar inverted, high performance device structure, Glass/MoO3/Cs2TiBr6/SnO2/Au, is evolved, which is a promising eco-friendly device that can be used for making solar panels without any toxic consequences. The short circuit current density, the open circuit voltage, power conversion efficiency, and the fill-factor of this innovative inverted solar cell structure are observed to be 16.589 mA/cm2, 1.1 V, 15.68 %, and 85.76 %, which are significantly better parameters than those previously reported.

Metal oxide nanoparticles as an electron-transport layer in perovskite solar cell

The research on the application of lead-free perovskite materials as an active layer in solar cells has been positively carried out for the last few years. Although the efficiency of lead-contained metal halide-based Perovskite has reached above 25%, but lead is a highly toxic substance that is hazardous to the environment, and this is one of the obstacles to their commercialization. In this article, a Sn-based Perovskite (CH3NH3SnI3) solar cell with two distinct electron transport layers was simulated using GPVDM (General Purpose Photovoltaic Device Model) and fabricated with a simple sol-gel method. Along with the absorber layer, the charge transport materials also play an essential role in extracting electrical power. The comparison of ZnO and TiO2 as electron collectors has been investigated and characterized, the hole-carrying layer has been eliminated for better findings. Remarkably, we achieve an efficiency of 7.33% and 6.75% in simulation and 6.90% and 5.81% from fabricated devices using ZnO and TiO2, respectively.

Progress in theoretical study of lead-free halide double perovskite Na2AgSbX6 (X = F, Cl, Br, and I) thermoelectric materials

Herein, we have studied progressively novel metal lead-free halide double perovskite renewable energy materials. Due to their potential use in electronic devices, researchers have investigated these materials with a lot of interest. From the electronic structure, we have found that these are the indirect band gap semiconductors within the range between 1.273 and 3.986eV. Optical parameters such as dielectric constant, electrical conductivity, and absorption coefficient have also been investigated, which have shown that these materials have potential use in photovoltaics. We have checked stability issues by thermodynamic parameters and phonon spectra. We have found them thermally stable; however, the phonon spectra show their dynamical instability and except for Na2AgSbF6 and Na2AgSbI6, the remaining compounds are weak in mechanical stability. For another futuristic purpose, thermoelectric parameters such as Seebeck coefficient, power factor, and figure of merit have also been calculated, which again verifies that these materials may be very useful in thermoelectric devices. Most of the parameters have been computed for the first time. We have performed this computational work using WIEN2k simulation code, which is based on the full-potential linearized augmented plane wave (FP-LAPW) technique. It is one of the most reliable techniques to calculate the photovoltaic properties of semiconducting perovskites. The interaction between ion-core and valence electrons was dealt with within the PAW technique as implemented in Vienna Ab initio Simulation Package (VASP).

Investigation of structural, electronic, elastic and optical properties of Ge-halide perovskites NaGeX3 (X = Cl, Br and I): A first-principles DFT study

Lead-free perovskites are among materials that are currently most investigated for their potential application in photovoltaic and optoelectronic applications due to their non-toxic effect on the environment. In this study, a first-principle Density Functional Theory (DFT) calculation to study structural, elastic, electronic, and optical properties of Ge-halide perovskites namely cubic NaGeX3 (X = Cl, Br, and I) is presented and reported for the first time. The Quantum Espresso code with GGA-PBE functional was used for conducting the DFT calculation on these lead-free perovskite materials. The structural investigation revealed that the optimized lattice constants for NaGeCl3, NaGeBr3, and NaGeI3 are 5.24 Å, 5.50 Å, and 5.90 Å, respectively. Meanwhile, all compounds are shown to possess semiconducting behaviour and have direct R→R energy bandgap. Consistent with other isoelectronic compounds, it is observed that the energy gaps are tuned to slightly lower values as Cl is replaced by Br and I, with energy gaps 0.76 eV, 0.45 eV, and 0.44 eV for the respective compounds. From their Bulk modulus and other elastic parameters calculated, the materials are stable and ductile, making them easily incorporated into thin films in solar cells and other applications. The materials also exhibit excellent optical properties including high absorption coefficient and therefore they have the potential to be used in developing lead-free perovskite solar cells and other optoelectronic applications.

Tunable and Efficient Photoluminescence of Lanthanide-Doped Cs2NaScCl6 Double Perovskite Single Crystals toward Multifunctional Light-Emitting Diode Applications.

Lead-free halide double perovskite, as one of the promising candidates for lead halide perovskite materials, shows great potential in light-emitting diodes (LEDs), benefiting from its environmental friendliness and high chemical stability. However, the poor regulation of the emission spectra severely limits its application range. Herein, various lanthanide ions were successfully doped in Cs2NaScCl6 double perovskite single crystals (DPSCs) to yield effective and stable emissions spanning from visible to near-infrared (NIR) regions. Notably, efficient energy transfer from the host to the dopants enables tunable emissions with good chromaticity, which is rarely reported in the field of lead-free double perovskite. Moreover, density functional theory calculations reveal that the high local electron density around the [LnCl6]3- octahedron in DPSCs plays a key role in the improvement of photoluminescence quantum yields (PLQYs). The optimal PLQYs are up to 84%, which increases around 3 times over that of the undoped sample. Finally, multicolor and NIR LEDs based on Ln3+-doped Cs2NaScCl6 DPSCs were fabricated and had different application functions. Specifically, the single-composite white LED shows adjustable coordinates and correlated color temperatures, while the NIR LED shows good night vision imaging. This work provides new inspiration for the application of efficient multifunctional LEDs based on lead-free double perovskite materials.

Design and simulation of chalcogenide perovskite BaZr(S,Se)3 compositions for photovoltaic applications

Lead-free Perovskite materials have acquired a lot of interest owing to their potential to overcome the stability and toxicity concerns compared to traditional perovskite solar cells. Chalcogenide perovskites (ABX3, where A = Ba, B = Zr, X = S and/or Se) are emerging materials for photovoltaic (PV) applications. Computer-based designing of metal chalcogenide semiconductors, resulting in the identification of extremely appealing ABX3 substances and their derivatives that may be used as absorbers in thin-film PV devices. In this context, here the numerical studies are performed using the SCAPS-1D simulator for designing of chalcogenide perovskites-based solar cells. We used FTO (Fluorine-doped tin oxide), TiO2 as electron transport layer (ETL), BaZrS3, and BaZrSe3 as an absorber layer, Spiro-OMeTAD as a hole transport layer (HTL), and Au as a metal back contact. The simulations are conducted under AM 1.5G solar spectrum designed to maximise the efficiency of the proposed solar cell. The selection of the optimal parameters such as thickness, defect density and temperature for all the layers including absorber, FTO, ETM, and HTM is examined. The parameters are considered, keeping in mind their impact on solar cell performance, budget effectiveness, and the physics of the entire solar cell architecture. The effect of temperatures between 300 K to 450 K is studied. The results indicate that the power conversion efficiency (PCE), FF (fill factor), Voc (Open Circuit Voltage) and Jsc for BaZrS3 is 12.12%, 79.40%, 0.70 V, 22.00 mA cm−2, respectively, whereas for BaZrSe3 it is 25.84%, 77.32%, 0.72 V, 46.65 mA cm−2, respectively. This shows that BaZrSe3 has the potential to replace BaZrS3.

Room-temperature synthesis of lead-free copper(I)-antimony(III)-based double perovskite nanocrystals

In the field of perovskite solar cells, explorations of new lead-free all-inorganic perovskite materials are of great interest to address the instability and toxicity issues of lead-based hybrid perovskites. Recently, copper-antimony-based double perovskite materials have been reported with ideal band gaps, which possess great potential as absorbers for photovoltaic applications. Here, we synthesize Cs2CuSbCl6 double perovskite nanocrystals (DPNCs) at ambient conditions by a facile and fast synthesis method, namely, a modified ligand-assisted reprecipitation method. We choose methanol as a solvent for precursor salts as it is less toxic and easily removed in contrast to widely used dimethylformamide. Our computational structure search shows that the Cs2CuSbCl6 structure containing alternating [CuCl6]5− and [SbCl6]3− octahedral units is a metastable phase that is 30 meV/atom higher in energy compared to the ground state structure with [CuCl3]2− and [SbCl6]3− polyhedra. However, this metastable Cs2CuSbCl6 double perovskite structure can be stabilized through solution-based nanocrystal synthesis. Using an anion-exchange method, Cs2CuSbBr6 DPNCs are obtained for the first time, featuring a narrow bandgap of 0.9 eV. Finally, taking advantage of the solution processability of DPNCs, smooth and dense Cs2CuSbCl6 and Cs2CuSbBr6 DPNC films are successfully fabricated.

Two-Dimensional Cs2 AgInx Bi1-x Cl6 Alloyed Double Perovskite Nanoplatelets for Solution-Processed Light-Emitting Diodes.

Lead-free double perovskites have emerged as a promising class of materials with potential to be integrated into a wide range of optical and optoelectronic applications. Herein, we demonstrate the first synthesis of two-dimensional (2D) Cs2 AgInx Bi1-x Cl6 (0 ≤ x ≤ 1) alloyed double perovskite nanoplatelets (NPLs) with well controlled morphology and composition. The obtained NPLs show unique optical properties with the highest photoluminescence quantum yield of 40.1%. Both temperature dependent spectroscopic studies and density functional theory calculation results reveal that the morphological dimension reduction and In-Bi alloying effect together boost the radiative pathway of the self-trapped excitons of the alloyed double perovskite NPLs. Moreover, the NPLs exhibit good stability under ambient conditions and against polar solvents, which is ideal for all solution-processing of the materials in low-cost device manufacturing. We demonstrate the first solution-processed light-emitting diodes using the Cs2 AgIn0.9 Bi0.1 Cl6 alloyed double perovskite NPLs as the sole emitting component, showing luminance maximum of 58cd/m2 and peak current efficiency of 0.013cd/A. Our study sheds light on morphological control and composition-property relationships of double perovskite nanocrystals, paving the way toward ultimate utilizations of lead-free perovskite materials in diverse sets of real-life applications. This article is protected by copyright. All rights reserved.

A universal hydrochloric acid-assistant powder-to-powder strategy for quick and mass preparation of lead-free perovskite microcrystals

Lead-free halide perovskite materials possess low toxicity, broadband luminescence and robust stability compared with conventional lead-based perovskites, thus holding great promise for eyes-friendly white light LEDs. However, the traditionally used preparation methods with a long period and limited product yield have curtailed the commercialization of these materials. Here we introduce a universal hydrochloric acid-assistant powder-to-powder strategy which can accomplish the goals of thermal-, pressure-free, eco-friendliness, short time, low cost and high product yield, simultaneously. The obtained Cs2Na0.9Ag0.1In0.95Bi0.05Cl6 microcrystals exhibit bright self-trapped excitons emission with quantum yield of (98.3 ± 3.8)%, which could retain (90.5 ± 1.3)% and (96.8 ± 0.8)% after continuous heating or ultraviolet-irradiation for 1000 h, respectively. The phosphor converted-LED exhibited near-unity conversion efficiency from ultraviolet chip to self-trapped excitons emission at ~200 mA. Various ions doping (such as Cs2Na0.9Ag0.1InCl6:Ln3+) and other derived lead-free perovskite materials (such as Cs2ZrCl6 and Cs4MnBi2Cl12) with high luminous performance are all realized by our proposed strategy, which has shown excellent availability towards commercialization.

High-throughput calculation and machine learning of two-dimensional halide perovskite materials: Formation energy and band gap

Both band gap and stability of halide perovskites are prerequisites for deployable photovoltaic devices; however, many machine learning researches focus on one target output and a systematic machine learning workflow for achieving multiple targets is desirable. In this manuscript, we employ machine learning (ML) coupled with high-throughput density functional theory (DFT) calculation to predict potential two-dimensional lead-free halide perovskite materials with appropriate band gap and stability for solar cell applications. This is realized by the construction of two machine learning models based on the random forest algorithm with each targeting on band gap or formation energy, followed by the candidate intersection for the materials screening. The multi-objective DFT+ML framework predicts three possible lead-free two-dimensional halide perovskite materials with suitable stability and band gap, which are further evaluated via the molecular dynamics to evaluate their thermodynamic stability. Their spectroscopic limited maximum efficiencies (SLMEs) are calculated to confirm their photovoltaic capabilities. In order to comprehensively evaluate the features, new descriptors for the halide perovskite materials with better correlation with the target output are automatically formulated via symbolic regression based on genetic algorithms, and an alternative feature analysis method based on the literature textual data and natural language processing (NLP) is proposed. Post hoc analysis is performed via DFT and molecular dynamics to provide more detailed information on the materials prediction. This study highlights the developments multi-objective machine learning workflow for inverse materials design and analysis.

Numerical Simulation and Optimization of Inorganic Lead-Free Cs3Bi2I9-Based Perovskite Photovoltaic Cell: Impact of Various Design Parameters

The lead halide-based perovskite solar cells have attracted much attention in the photovoltaic industry due to their high efficiency, easy manufacturing, lightweight, and low cost. However, these lead halide-based perovskite solar cells are not manufactured commercially due to lead-based toxicity. To investigate lead-free inorganic perovskite solar cells (PSCs), we investigated a novel Cs3Bi2I9-based perovskite configuration in SCAPS-1D software using different hole transport layers (HTLs). At the same time, WS2 is applied as an electron transport layer (ETL). Comparative analysis of the various design configurations reveals that ITO/WS2/Cs3Bi2I9/PEDOT:PSS/Au offers the best performance with 20.12% of power conversion efficiency (PCE). After optimizing the thickness, bandgap, defect density, and carrier density, the efficiency of the configuration is increased from 20.12 to 24.91%. Improvement in other performance parameters such as short circuit current (17.325 mA/cm2), open circuit voltage (1.5683 V), and fill factor (91.66%) are also observed after tuning different attributes. This investigation indicates the potential application of Cs3Bi2I9 as a lead-free and stable perovskite material that can contribute to improving the renewable energy sector.

Design and Device Numerical Analysis of Lead-Free Cs2AgBiBr6 Double Perovskite Solar Cell

The advancement of lead-free double perovskite materials has drawn great interest thanks to their reduced toxicity, and superior stability. In this regard, Cs2AgBiBr6 perovskites have appeared as prospective materials for photovoltaic (PV) applications. In this work, we present design and numerical simulations, using SCAPS-1D device simulator, of Cs2AgBiBr6-based double perovskite solar cell (PSC). The initial calibrated cell is based on an experimental study in which the Cs2AgBiBr6 layer has the lowest bandgap (Eg = 1.64 eV) using hydrogenation treatment reported to date. The initial cell (whose structure is ITO/SnO2/Cs2AgBiBr6/Spiro-OMeTAD/Au) achieved a record efficiency of 6.58%. The various parameters that significantly affect cell performance are determined and thoroughly analyzed. It was found that the conduction band offset between the electron transport layer (ETL) and the Cs2AgBiBr6 layer is the most critical factor that affects the power conversion efficiency (PCE), in addition to the thickness of the absorber film. Upon engineering these important technological parameters, by proposing a double ETL SnO2/ZnO1-xSx structure with tuned absorber thickness, the PCE can be boosted to 14.23%.

Device Optimization of a Pb-Free All Perovskite Tandem Solar Cell with 29.59% Power Conversion Efficiency

This study has focused on simulating a highly efficient lead-free all-perovskite tandem solar cell using the SCAPS 1D device simulation tool. In the tandem structure, the top cell used Cs2AgBi0.75Sb0.25Br6 (Eg = 1.80 eV), and the bottom cell used FAMASnGeI3 (Eg = 1.40 eV) as the absorber material. Also, ZnO and NiOx were used as the electron transport layer (ETL) and the hole transport layer (HTL), respectively. Primarily the individual top cell and bottom cell have been optimized. The highest efficiency of the top cell was found to be 17.13% with performance parameters VOC = 1.23V, JSC = 15.57 mA/cm2 and FF = 89.39%, whereas the optimized efficiency of the bottom cell was found to be 17.58% with performance parameters VOC = 0.85V, JSC= 27.38 mA/cm2 and FF = 75.34%. The thickness of the absorber of the top cell and bottom cell shows a significant impact on the device performance and the optimum thickness for the Cs2AgBi0.75Sb0.25Br6 absorber layer was found to be 400 nm, whereas for the FAMASnGeI3 layer was found to be 200 nm. Careful optimization of the tandem device has resulted in an improvement of the performance and obtained an efficiency of 29.59 %, with JSC of 17.50 mA/cm2, VOC of 2.09 V, and FF of 80.87%. The final simulated device sums up tremendous potential for the fabrication of a highly efficient PSC device using lead-free perovskite materials towards excelling commercialization.

Design and Simulation of Lead-free Flexible Perovskite Solar cell Using SCAPS-1D.

Despite perovskite solar cells’ rapidly increasing efficiency, industrializing and commercializing the device presents several challenges. Top among these is toxicity due to the material’s lead-based perovskite usage, which causes rapid degradation. Because of this challenge, researchers have recently become interested in lead-free perovskite materials. In this research, we investigate using the SCAPS simulation software to optimize a lead-free flexible solar cell. Lead (Pb), which belongs to group 14, can likely be replaced with bismuth (Bi), which belongs to group 15. In this study, the structure of the device is an n-i-p planar lead-free heterostructure flexible perovskite solar cell (FPSC) comprised of a Polyethylene Terephthalate/Indium Tin Oxide (PET/ITO) substrate; [6,6]-phenyl C61 butyric acid methyl ester (PCBM) Electron Transport Layer (ETL); methyl ammonium bismuth iodide (CH3NH3BiI3) as an absorber; Spiro-OMeTAD as a Hole Transport Layer (HTL); and silver (Ag) as the electrode. We optimised cell performance and efficiency with an absorber layer of 100 nm and an optimised temperature of 300 K. This absorber layer’s thickness and defect density were considered. The defect density of the FPSC is indirectly proportional to the device’s absorption coefficient (alpha). We obtained a power conversion efficiency (PCE) of 18.80%, a current density (JSC) of 35.59 mA/cm2, an open circuit voltage (VOC) of 0.633 V, and a fill factor (FF) of 83.43%. We also observed that the FF is inversely proportional to the thickness of the absorber layer of the FPSC.